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T-FLEX Analysis. User Manual

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1. Time 36 00 c Max 92 81 100 00 78 75 B Thermal Flux magnitude PBHALSBUAAS Q ot mi Q Q Q s E 100 00 79 01 58 02 37 04 Mo 3 3D E Stu Ef Pro SI Hide Construction Enter command or select element Examples of a steady state left and transient right thermo dynamical processes Details of Thermal Analysis Steps Thermal analysis is performed in several stages The sequence of the user s steps for putting together a study and running a thermal study of a structure is in many parts similar to algorithms of working with other study modules of T FLEX Analysis Therefore we will point out in this chapter only certain details specific to thermal studies 1 Creating Study When creating a study specify its type Termal Analysis As in other study types building a finite element mesh is required for approximating the structure s geometry 2 Applying boundary conditions In the thermal analysis the boundary conditions are represented by the boundary and initial temperatures heat power sources heat flux and conditions of heat exchange between the model and environment convection and radiation applied to the model 107 T FLEX Analysis User Manual 108 3 4 Title Block Analysis Parameters Tools Customize View 5 m va New Study TUSE JEN i 0 Studies
2. visual Scale 1 Example of non uniform load distribution function obtained by using linear interpolation Direction of Load For a direction of the Force the user can select the normal to the loaded face the element of a 3D model or a radius vector specified in the selected by the user local coordinate system if the local coordinate system is not specified the global coordinate system will be used by default To work with the local coordinate system use the following options For specifying direction of the force with the help of an object of a 3D model use the following automenu option lt D gt Select direction To cancel selection of direction use the option Si lt U gt Cancel direction selection For a quick change of Force direction to reverse the user can turn on the flag Reverse direction Bending Moments 46 In the dialog Force parameters in addition to parameters defining the load type numeric value units load direction etc there is a group of parameters called Moment Preparing Finite Element Model for Analysis Preprocessor Force Parameters x Common Load Parameters Face_1 Extrusion_O surface Distribution niforn f Uniform Load Value E Units fn Direction Normal ai 1 Element Y po a cs XM 2 gt Sy D Reverse Direction Torque E Torque M m M Torque Y r Torque Z M m Units 1 h m Set as default Cancel
3. With the help of parameters of this group the user can specify bending moments with respect to the axes of the coordinate system local or global for solving problems of plate deformation It is important to note that computational domain was discretized with the triangular finite elements For the Moment the user can utilize the following units N m lbf in kgf cm In the 3D scene the load Force is shown with arrows The arrows show the direction of the load In many cases the distributed load has to be applied only to a certain part of the edge or face corresponding to the domain of action of the external load and not to the entire face or edge of the model To apply the load to the part of the face first the geometry of the desired shape must be created on the face and then the command Operation Faces Imprint Elements should be used at edge at face at vertex Specifying load Force 47 T FLEX Analysis User Manual Typical sequence of steps for specifying the load Force A Initiate command Force Specify the load magnitude Specify the units Select the load type uniform or non uniform Specify the direction of load action CONN NN BWN Complete the command Pressure Select face edge vertex node or a sequence of elements For a non uniform load specify the qualitative distribution law Pressure represents a loading type used for specifying a distri
4. T FLEX Analysis T FLEX ANALYSIS USER MANUAL oscow 2008 Copyright 2008 Top Systems This Software and Related Documentation are proprietary to Top Systems Any copying of this documentation except as permitted in the applicable license agreement is expressly prohibited The information contained in this document is subject to change without notice and should not be construed as a commitment by Top Systems who assume no responsibility for any errors or omissions that may appear in this documentation Trademarks T FLEX Parametric CAD T FLEX Parametric Pro T FLEX CAD T FLEX CAD 3D T FLEX CAD Analysis are trademarks of Top Systems Parasolid is a trademark of Siemens PLM Software All other trademarks are the property of their respective owners Edition 4 Table of Contents TABLE OF CONTENTS latroduc hiom aaen cass colaccans soees secesaueteseatdese ce E a A 5 About Mathematical Background of T FLEX Analysis ccccccccccccccccccccccceceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeey 5 Technical Req mire mens seen R ee 8 ComM CC UNE ICING cei i a a as bane a aetna bots ateacnneied tues teases 8 Recommended computer parameters for efficient professional work with T FLEX Analysis ccccccccceeeees 8 T LCEX Analysis Systemi Installat Onsese a E eeiadaartahacuetause cestasaaueiauianten 8 Structural Organization of T FLEX Analysis Application cccccccssssseeesssssssessssssse
5. lt D gt Select direction To cancel selection of direction use the option ah lt U gt Cancel direction selection For a quick change of Force direction to reverse the user can turn on the flag Reverse Direction 43 T FLEX Analysis User Manual Force as a Total Magnitude of Non uniformly Distributed Load 44 When defining the Force as a total magnitude of non uniformly distributed load in addition to the numeric value units and direction of its action it is required to specify a qualitative distribution law according to which the load will be distributed over the face area Force Parameters Ea Common Load Parameters Face 38 Distribution Nonuniformn Distribution Overall Force fiooo 4 Interpolation Spline Value ioo 4 Units kgf a Columns j2 Roms j2 5 set Export Import visual Scale 0 001 Direction M Normal a Element y To LCS zf lt E Reverse Direction Set as default Cancel Value We will define the numeric value of the force as a total magnitude of load non uniformly distributed over the face area Units For the Force the following units can be used N lbf kgf Distribution Law On the rectangle circumscribing the face selected as the domain of application of non uniform load a uniform grid of nodes is generated The density of grid is determined by the number of rows and columns in the distribution table The valu
6. JLuniForrn gt Uniform Load Value 1o00 Units imez Direction F Normal Element Les LESO E Reverse Direction E Set as default Preparing Finite Element Model for Analysis Preprocessor local coordinate system is not specified the global coordinate system will be used by default By default in the local coordinate system the direction of load is set along the X axis To work with the local coordinate system use the options To specify the direction of the load Pressure with the help of a 3D model use the automenu option lt D gt Select direction To cancel selection of direction use the option cir lt U gt Cancel direction selection For a quick change of load direction to an opposite one the user can activate the flag Reverse direction Pressure as a Non Uniformly Distributed Load When defining the Pressure as a non uniform load it is necessary to specify the units direction and distribution law according to which a given load will be defined at each point of a face Pressure Parameters Common Load Parameters Face 7 Distribution Nonuniform E Distribution Overall Force Interpolation Spline Value jf Units Injmaz l Columns E Rows e 4 Export Import Visual Scale 0 000001 Direction IY Normal Element LEs E Reverse Direction Set as default Cancel Distribution law On the rectangle circumscri
7. Type Linear Static window and in the report Comment The Type control serves for defining the study type zi Note that T FLEX Analysis allows changing an existing study type to another one from the list of study types available to the user For example the user can create a study of the Static Analysis type and then change the type for example to Stability or Frequency Materials analysis thickness Hf The Comment edit box lets the user entering arbitrary text information pertaining to the current study This information will be used in the future for Cancel Help generating a report based on the study solution results Operations IY Display this dialog box before solving The Solve tab serves for defining processor properties for solving linear statics equations 89 T FLEX Analysis User Manual 90 The control elements in the Calculation method group lets the user define the methods of solving systems of algebraic equations of linear statics Direct method The system of equations is solved by Gauss method via LU decomposition of the stiffness Bitdi matrix This method is effective for solving the system General Solve Nonlinear Thermoelasticity Results of equations constructed on the basis of the linear finite elements In certain cases the use of direct method can be also justified for analysis of the system with the help of quadratic finite elements It can be used i
8. o second cm ee Parameters tab of the thermal analysis study parameters window 1 Identity condition of finite element meshes in both thermal analyses The simplest way of achieving such identity is the use of the Copy command available in the context menu The sequence of steps can be for example as follows a create a study of the Thermal Analysis type generate a mesh define boundary conditions and run We assume that the solved temperatures will be used for defining initial temperatures in another study of the transient thermal analysis b create a study s copy using the Copy command c define boundary conditions of a transient study in thermal analysis On the Parameters tab of the study s properties select the name of the first study and if that s a transient analysis the desired time Step As aresult we have two studies of different types but with identical finite element meshes 2 The Calculate using linear element property on the Solve tab of the study parameters dialog should use the same settings in both studies For example if the first thermal analysis is done by linear elements then the second thermal analysis based on the former thermal analysis results can also be run only by linear elements Note also that solving a transient heat transfer study requires more CPU time as compared to the steady state heat transfer since in the former case the systems of algebraic e
9. A the plate thickness D 2a flexural l1 v rigidity Therefore the solution accuracy is 0 4 122
10. Analysis Load Bearing Force After invoking this command it is required to select elements cylindrical faces of the model for applying the load With the help of automenu option Select cylindrical face select a cylindrical face of an analyzed model The selected element will be added to the list In the properties window specify Common Load Parameters EA e Force distribution e Magnitude of load Sinusoidal Direction Lcs Units N kgf lbf Reverse direction e Direction of load value fi units fw Load direction As a direction of Bearing load the user can a select the element of a 3D model or coordinate axes of the Bi Setcechent Cancel global coordinate system For specifying the direction of Bearing load with the help of an object of a 3D model use the automenu option 55 T FLEX Analysis User Manual To cancel selection of direction use the option sinj lt U gt Cancel direction selection To change a direction of load to an opposite one the user can activate the flag Reverse direction In the 3D scene Bearing load is shown in the following way Specifying Bearing force A typical sequence of step for specifying Bearing load E 1 Initialize the command Bearing force 2 Select a cylindrical face or a set of faces 3 Specify the magnitude of load 4 Specify the load direction 5 Complete the command Torque Torque is the impact of a force mo
11. Defmine Restralnis srianan A alias ie Daten 38 FURESTA enea aaaae a eats eiotetincneato tat uate Soa ated contaasodies 38 RUNS Gch Bokeh cl Ree eee eee ee een err oe ere hoe ee Mee eee eee rene er ne ere etre cere eee eer een ee rere eee 38 OU CL ea 40 Sim TO AGS sg ets atc a aa a eede eee eR 42 ITC Neat AUTO AAS seks stacasoes dns a ete Nace uc e tare Sadeca cules EE cnclaeuseesedleane 42 TOE CG wesc tate ee eta set E E E E a edaie ieeanest ates 42 MESS SUE Sere ety eee ecg AE EAE EENE A AEEA E E NAE nee a Neola te CAT E EA AEEA EEN 48 ODE aR O ege a nee E E E E a Ce Rane ann N 52 POC Er O terns cate e A TE e a a a a a iad teats 53 Beare TONG enan E A 55 T S53 ec E N a 56 Thermal Loads saken a E a a N 57 USS EM F as etcetera etecr ese anes as eae tin eiectadle nas eaten ae r a edt tha Secatete Pomenosea R 58 EEE R EA ii o acre as ane P E E EE aarti nade E E E E A E EA EAEE EE E EO A E acetate 59 PEPON O ao E reese tana ease ane teceureaneoct ope ataataueonnans 60 CO Ci OI acne sain theta haciatsaestacetua E ania utasbalt E eatue Maina done 61 RETE ON iat escheat A TETA ade ce fi A A NE E adeno ETE A Sasser cede ta A E tines Tid ade EE mance A 62 Loads Compendium Vaile isp pisces trae E baat ian alice E Mies OEA 63 T FLEX Analysis User Manual Edine Loadsand RestainiS amen me nee nea eee nme ene es ene em mene nee 64 Customization and UW tility Command sista sacedisartend e E E eee 65 Working with the 3D Window when Preparing
12. E E Coloring Properties 1 67 4462277E 006 Properties O 00000000E 000 Fie PECHES Use of the floating bar for controlling deformed state display and animation Frequency This parameter sets the rate at which the full animation cycle completes The number stands for the fraction of a minute in which the full animation cycle completes Variable coloring Controls color variance during animation Changes in colors can be synchronized with changes of the deformed state from zero to final values When showing negative deformations the colors are not inverted Negative values This option enables the mode in which the results displayed during animation first reach zero and then go to the values equal to the calculated ones but with the opposite sign This creates the vibration effect of the calculated model as 1f the load were periodically changing its sign to the opposite Solids lets you manage the bodies in the Postprocessor window which are part of the assembly model when evaluating assemblies The user can tune of the flags corresponding to one or many parts of the assembly after which those will no longer be displayed in the postprocessor window By using the Opacity control you can also manage transparency of the assembly parts displayed in the calculation results window These tools help visualize the result fields inside the assembly model by temporarily hiding obstructing objects Display
13. Load Factor 53 94 lj Jo Buckling Mode 2 Load Factor 268 19 I 3 9806E 004 2 7919E 004 2 9915E 004 2 0982E 004 1 9903E 004 1 3959E 004 1 0013E 004 0225E 005 0 0000E 000 0 0000E 000 Buckling modes corresponding to the first and second critical loads on the part Algorithm for Buckling Analysis Based on Modeling Once the study calculation completes successfully you should analyze solution results in order to make conclusions on probabilistic buckling of the structure based on results of Finite Element modeling A typical sequence of steps for validating the results of Finite Element modeling of initial buckling is as follows l 2 Solution evaluation As was mentioned earlier the Load Factor must be positive If the factor came out negative that means the loads applied to the structure do not produce system buckling Load factor evaluation If the Load Factor is positive and is less than 1 that means system buckling will occur under the specified loads and that the design of the structure needs enhancement If the Load Factor is positive and is greater than 1 that means there is no buckling threat for the structure under the specified loading conditions Buckling modes analysis In the studies tree use the context menu command Open or Open in new window to open the Buckling mode 01 solution corresponding to the smallest critical loading We can visually estimate the pattern of the strained state of
14. Selected elements are added to the list Temperature Parameters Common Load Parameters In the properties window of the load Temperature it is Initial Temperature required to specify the following parameters Temperature e The magnitude ofthe load e Units K C F In the 3D scene the Temperature is shown in the following I Set as default Cancel way Specifying thermal load Temperature Specifying initial temperature in transient thermal analysis Preparing Finite Element Model for Analysis Preprocessor A typical sequence of steps for specifying the thermal load 1s 1 Initialize the command Temperature EJ 2 Activate option Temperature or Initial temperature 3 Select body face edge vertex or a set of elements 4 Specify the value of temperature and units 5 Complete the command Heat Flux Load Heat flow allows the user to specify the amount of heat transferred across the unit surface area per unit of time that is define a specific heat flow For specifying the load use the command Keyboard Analysis Thermal Load Heat tA lt 3TF gt S one Flow Heat flow can be applied to faces of the model For selecting faces use the automenu option Selected elements are added to the list Heat Flux Parameters In the properties window of the load Heat flow it is required Common Load Parameters to specify the following parameters SRM vue o e The load magnitude un
15. Solve tab of the study parameters dialog should use the same settings in both studies For example if the thermal analysis is done by linear elements then the static analysis based on thermal analysis results can also be run only by linear elements The Results tab allows defining the result types displayable in the studies tree after finishing calculations Save solving results in file enables the mode in which all analysis results are saved in the file together with the model This allows analyzing results of an earlier calculated and saved study without the need for a 91 T FLEX Analysis User Manual 92 new calculation Please note that saving calculation results in a document increases the size of the document file by approximately 4 5 to 5 Mbyte per a hundred thousand Degrees of Freedom The tab Nonlinear allows the user to carry out statical analysis taking into consideration large RRR x displacements General Solve Nonlinear thermoelasticity Results In practice there are situations in which displacements of certain points of the structure reach significant values under the action of external loads These problems are especially important in aircraft and space industry when designing radio telescopes cooling towers and other thin walled structures In these cases the nonlinear effects should be taken into consideration since the assumptions on which the linear analysis is built are not valid MV
16. i 1 0000 e727 a 6 1853 38 9993 241 2242 1520 9490 In this case we are interested in the zones in which the FS approaches critical values We can scan the model using the mouse and pointing it at the places of interest getting the result in the pop up tooltip However for better visual representation of such zones let s set up the color scheme as shown on the next figure 19 T FLEX Analysis User Manual Range TRS d Scale Linear Logarithmic 1 57004 Maximum espa automatically i value al 1 72305 Task Study_0 Minimum 4 Factor of safety automatically eis Min 0 6027 lt a value 1 88988 1 5000 P amp bsolute value 1 97926 Colour Spectrum Scheme Standard SAVE F 1 7830 M Gradient IW Reverse Load 2 1709 Threshold level D 2 27357 Level z a g E 2 3811 sate 2 49371 we Display minimum on top E 4 I Display marks 2 61165 W Number of marks 2 73517 M Display Zero Mark 2 5191 M Show maximum always 2 66452 M Show minimum always 4 3 E Default Cancel Apply 3 0000 l Max 1520 9490 We specify the range of values of interest from 1 5 to 3 For convenience we will correct color assignments Anything greater than 3 will be displayed White we are not interested in those zones for the time being The critical zones with the value below 1 5 will be Red The rest of the values in the
17. ones 19 T FLEX Analysis User Manual Fon amp T FLEX Parametric CAD C Mphmepbi Body grb Eile Edit Construct Draw Operation Title Block Analysis Parameters Tools Customize View Window Help l lpwacdla F p Default 6 amp 0 Studies Body grb Study_O a Body _0 H A Mesh 0 H E Restraints 1 H E Loads 1 i Results 4 B Displacement magnitude Equivalent Strain B Equivalent Stress B Factor of safety by equivale I stu Alo Studies ajx 7O k S LAA A lO lL o oR 0 EE SF lY ZAA y YX 8 Body grb Study _0 t Body grb Task Study_0 Displacement magnitude m Displacement scale 2404 76 2 61829E 006 2 10598E 006 1 40915E 006 6 9683E 007 t lal ish S OPNE MSs te Bll Meshed model display management The functionality is accessed by double clicking in the solution viewer window or by the context menu command Properties The user can specify various modes of displaying calculation results over the mesh without mesh with or without displaying contour of the original part and other bodies present in the assembly displaying deformed state animating the image etc Animation allows recreating the studied model behavior under a smoothly varying loading with simultaneous display of stress or displacement fields corresponding to the varying load F File Edit Construct Draw Operation Title Block Analysis Parameters Tools Customize view W
18. Edit Construct Draw Operation Title Block Analysis Parameters Tools Customize view Window Task Study_0 Temperature C Time 600 00 c 8 06738510E 001 Render Projection Rotate TU OS il B Thermal Flux magni B Temperature 31 Clip plane 6 58644333E 001 Canai IA Labels RT Coloring Properties Properties 5 10550156E 001 3 62455673E 001 MWERI IES T S 2 15695744E 001 A Time process Use of the Time process window for managing access to the results of a transient thermal study lt m E gt Show Window Time Process Thermal Analysis Processor Settings On the General tab you can define or edit the descriptive attributes of the current study as the name or a comment The Solve tab contains settings for solving systems of algebraic equations with their meanings similar to the settings of the Static analysis study see the respective section Note that the Calculate using linear element mode can be used in most cases of thermal analysis facilitating much faster calculations Unlike studies in Statics Frequency analysis and Buckling results of temperature distribution over the model s volume achieved under the linear interpolation assumption are not much different from the respective results obtained from using a quadratic interpolation Before starting calculations on the tab Parameters the user can indicate the type of solved thermal a
19. Expression get Sensor_0 STRAIN EQUIVALENT Create Mame_of_variable Replace faa ka Steps of sensor creation Sensor is designed for extracting results of calculation of a finite element analysis problem in a specified by the user point To do that first the user has to solve the finite element analysis problem even 1f the problem has already been solved and then from the context menu invoked on selecting Sensor with a right mouse button in the window Studies call the command Measure From the appeared properties dialog in the Table Property the user can select the desired type of result and view its value Clarification for the keywords located in the first column of the table is given in the field Definition below the table Selected value can be saved with the help of the option Variable To do that select the option Create in the group Variable specify the name of the variable and press the button Apply Sensors are also used for extracting control data when solving optimization problems using the results of the finite element calculations Generating Reports 76 The user can create electronic documents containing basic information about a calculated study which are independent of T FLEX Analysis Reports are generated in the html format so that viewing them is possible in any browser for example MS Internet Explorer or MS Word To create a report of the active s
20. Firstly quality of a solution may depend on the shape of the involved finite elements Best results of finite element modeling are achieved if the elements tetrahedrons and triangles forming the meshed model are close to equilateral ones This is especially important for tetrahedral elements Vise versa if a meshed model contains elements whose element generating edges vary in their size greatly then the modeling results could be of an insufficient accuracy In such cases it is desirable to minimize the number of such improper elements by means of the options provided in the finite element mesh generator Poor mesh of finite element model Good mesh of finite element model 25 T FLEX Analysis User Manual Thus a user needs to control quality of the constructed finite element model based on a visual inspection or with the help of Grid settings aiming at possibly more uniform shape distribution of the elements involved in the mesh More adequate mesh obtained after using mesh parameters settings Secondly besides the shapes of the finite elements the solution quality is directly affected by the degree of discretization of the original geometrical model that is density of the finite element mesh The user can control this mesh generator s parameter by specifying a relative or absolute mean size of the finite elements approximating the body geometry or by varying parameters that affect mesh generation on curvili
21. M Relative miscalculation 0 001 Maximal iteration number 400 Finite Elements Method T Calculate using linear element e turn on the option Non Stationary System in case if the restraints applied to the model are not sufficient to eliminate the model s rigid body motion in space In the group Solving Equations for parameter Solving System it is required to indicate possibility of using additional disk memory Customize automatic not available mandatory The use of additional memory allows the user to save decomposition of the stiffness matrix For preliminary draft calculation anly without using numerical data For own modes Frequencies estimation Mass matrix diagonalization aa He _ Relative miscalculation the error of evaluating the natural frequencies after reaching which the iterative process terminates Maximum number of iterations the critical number of iterations after reaching which the iterative solving of the system of equations terminates even if the required solution precision was not achieved 105 T FLEX Analysis User Manual 106 In the group Finite Element Method the user can set the Calculate using linear element option if interested in qualitative results only that 1s when the one is only interested in relative assessment of vibration amplitude patterns Please note that a linear element solution provides insufficient accura
22. Options There are three options for using additional disk memory automatic not available mandatory The use of additional disk memory allows you to save the stiffness matrix decomposition Using additional disk memory for solving systems of equations is necessary only when the memory requirement for keeping intermediate matrixes exceeds the computer s RAM Note also that the running time for studies with a large number of dimensions using external storage could be significant due to a large number of operations on sequential data read write High volumes of disk storage may be needed for keeping intemediate matrixes up to several Gigabytes Make sure there is enough disk space before solving studies in large dimensions using external storage If the user disabled the the possibility of using the disk space while solving a high order system of equations an abnormal termination of the process may abort calculations in the event of the memory consumption for keeping the matrix decomposition approaching 2 Gigabyte for Windows 32 bit Finite Element Method By default all calculations use quadratic approximation for displacements regardless of what kind of finite element mesh was constructed for the model If the user is only interested in qualitative results that 1s he is only interested in relative distribution of stress fields using a rather fine mesh then one can use the linear element solution which runs much faster than the quadratic co
23. common physical phenomena and solve important practical problems arising in everyday design practice All calculations rely on the finite element method FEM At the same time an associative relationship is maintained between the three dimensional model of a part and the finite element model used in calculations Parametric notifications of the original solid model are automatically propagated into the meshed finite element model e Static analysis allows calculating the state of stresses and strains in a structure under the impact of constant in time forces applied to the model It is also possible to account for stresses building up due to thermal material expansion contraction or for structural deformations introduced by known displacements By using the Static analysis module the user can evaluate the strength of a structure developed by him with respect to admissible stresses identify the most vulnerable parts of the structure and introduce the necessary changes optimize the design e Frequency analysis allows calculating natural resonant frequencies of a structure and the respective vibration modes Based on the calculation results the product is assessed on the presence of resonant frequencies in the operating frequency range The developer can enhance reliability and performance of a product by optimizing the design in such a way as to exclude resonance occurrences e Buckling analysis is important when designing structures whose
24. computers and development of computer science led to big changes in traditional approaches to engineering calculations From the mid 60s of the 20th century the leading method of numerical solving a wide variety of physical problems became finite element method FEM The special features of the FEM that put it in the commanding position in the applied computational mathematics are such inherent qualities as T FLEX Analysis User Manual e versatility the method is suitable for solving all kinds of different problems of mathematical physics mechanics of deformable solids heat transfer electrodynamics e good algorithmization the suitability for developing software suites that cover a wide scope of applications e good numerical stability of FEM algorithms Emergence of personal computers and their increasingly wide use for design purposes impacted the accelerated development and availability of finite element analysis application systems that do not require the user to be deeply proficient in FEM theory eliminate labor intensive operations of manual preparation of initial data and offer excellent opportunities of processing results of mathematical modeling T FLEX Analysis belongs to modern finite element analysis systems oriented at a wide range of users who by the nature of their responsibilities face the requirement of assessing product behavior under conditions of various physical influences T FLEX Analysis is oriented at a
25. example a face with a force applied to it then you may need to manually edit this study element to account for changes in the model After updating this study data you will have to run calculations again to get up to date results Export Prepared initial data of each study can be exported in the Nastran dat format To export an active study use the command Keyboard Also this command is accessible via the context menu upon selecting the study E in the window Studies or in the window 3D model After calling the command the standard file saving dialog appears Next i you need to specify a combination of two properties of the format Short Long defines the precision of the output parameters the maximum number of digits in decimal positions including the decimal point short up to 8 decimal digits long up to 16 decimal digits Fixing Arbitrary defines the type of export data fixed data are output by columns of a fixed size arbitrary data are output separated by commas File Format Short Fixed Long Fixed Short Arbitrary 67 T FLEX Analysis User Manual PROCESSING RESULTS POSTPROCESSOR T FLEX Analysis Postprocessor serves for comprehensive examination of finite element modeling results A special feature of the T FLEX Analysis postprocessor is its deep integration with T FLEX CAD Calculation results are displayed in a separate window which is in many aspects of view
26. finite element 6 node curvilinear triangular finite element 4 node straight edged tetrahedral finite element 10 node curvilinear tetrahedral finite element 34 Preparing Finite Element Model for Analysis Preprocessor The use of curvilinear finite elements allows the user to more accurately approximate a complex geometry and obtain higher accuracy of the solution with the smaller number of elements Thus for more accurate description of the complex geometry of the boundaries it is necessary to use either a large number of the elements with the straight sides edges 1 e straight edged finite elements at the boundary or use curvilinear finite elements It is worth noting that with the same step of discretization creating the mesh with curvilinear elements requires more time than generation of the mesh with straight edged elements especially for the models with large number of radii and fillets In certain cases the mesh with curvilinear elements cannot be generated at all or its generation may take an unacceptably long time At the same time difference between the results obtained on the meshes curvilinear and straight edged finite elements as for example extreme displacements and stresses vanishes to zero when using a sufficiently fine discretization Consequently if constructing a mesh with curvilinear finite elements fails on a particular model of a complex geometrical shape or generating such a mesh takes too long time then
27. first mode corresponding to the minimum critical load Nevertheless the user may also say See mone f4 find the critical loads of other buckling modes Pes ioe Foni Solving System Customize W Relative miscalculation o ar Maximum number of iterations 100 General Solve Thermoelasticity Results In the group Finding State Forms for parameter Solving System it is required to indicate possibility of using additional disk memory Customize automatic not available mandatory The use of additional disk memory allows the user to save decomposition of the stiffness matrix on the disk El E Finite Element Method Calculate using linear element For preliminary draft calculation only without using numerical data For buckling load Factor estimation Cancel Help Relative miscalculation the accuracy of determining critical loads upon reaching this accuracy the iterative process stops Maximum number of iterations the critical number of iterations after reaching which the iterative solving of the system of equations terminates even if the required solution accuracy was not achieved In the group Finite Element Method the user can set the mode Calculate using linear element This facilitates much faster calculation for an approximate estimate of the buckling mode amplitudes relative distribution on a sufficiently fine mesh The linear element analysis provi
28. floating panels Deformed state and Time process respectively On the tab Document it is possible to activate the option of saving the calculation results in a separate external file By default the calculation results are saved in a main file of T FLEX extension grb When activating the external saving Se pean nc N erect of results the file with the name Document name Study name with extension tfa is created in the folder of the original document Is i option is set Results are stored in separate Files in Document Folder Processor Postprocessor Document This option can be useful for solving problems with large amount of results and also can speed up saving of the document depends on the operating system Cancel Help Working with the 3D Window when Preparing Study Elements As you work with studies various study elements can be displayed in the 3D scene loads restraints mesh Special commands are provided for handling those displays Keyboard a Analysis Show Loads Restraints 66 Preparing Finite Element Model for Analysis Preprocessor With this command you can enable or disable the mode of displaying all loads and restraints in the 3D scene This command is available in the context menu upon selecting a study studies Circular plate quarter grb El Study O f Body 1 og IES Ese E Fest Eea Edit H E Resul Pa Recreate A generated surface or volume
29. group of parameters provides control elements which define the visibility of auxiliary images around the calculated model for better results interpretation Mesh Controls visibility of the mesh facets in the calculation results window Loads Restraints Controls visibility of all boundary conditions employed in the current study The list of boundary condition types is displayed in a separate window Visibility of each element in this list can be controlled individually At the right of the window there are buttons for managing the list elements Using those buttons you can enable disable or invert visibility of all boundary conditions Model Contour By enabling this flag you make the contours of the original body subjected to the calculation appear as dotted lines in the calculation results window This capability can be helpful for comparing the deformed state of the model with the original 71 T FLEX Analysis User Manual Contours of all bodies Upon enabling this flag the rest of the bodies in the 3D scene that were not subject to the calculations are also displayed in dotted lines in the calculation results window Information Bar group of parameters contains controls for adjusting the amount of displayed textual and graphic information Coloring Scale This flag enables visibility of the color scale for more intuitive interpretation of the calculation results The scale range and colors can be customized see
30. if the value in the respective text field is not zero A cleared flag means no restraint is applied in this degree of freedom Preparing Finite Element Model for Analysis Preprocessor By default all displacements in all three directions are blocked If necessary the user can lift up existing restraints or add new ones Partial Restraint Parameters Common Restraint Parameters Restraint by Axes E meters WY meters Jo Coordinate System me meters Orthogonal fe ff Rotation 1 radians ss a Rotation z radians Units E Hrga Maai T T Rotation 3 e Angular radians Set as default Cancel Parameters Rotation about X Rotation about Y Rotation about Z are required to specify rotations with respect to the axes of the coordinate system local or global to solve problems of plate deformation Given that triangular elements must be used for discretization of the computational domain If the value of the rotation is equal to 0 it means that along this direction the rotation is fully restrained If the rotation value is not zero then the known rotation is specified The absence of flag option is turned off means that restraint of the rotation with respect to the given axis is not defined By default restraints of rotations with respect to the axes of the selected coordinate system are absent A cylindrical coordinate system allows 7 Restraint by Ames constraining displacements in
31. management is similar to a T FLEX CAD 3D modeling window Color coding of the calculated model can show all results There is also a tool for sampling exact values at any specific location on the model When displaying results the model can be shown in a scalable deformed state When a special animation feature is enabled one can dynamically view the pattern of changes in deformations from zero to the specified values General Principles of Working with Results The list of finite element calculation results available for viewing is displayed in the studies tree in the Results folder The list of results to be displayed in the studies tree is set up using the Results command of the context menu by G on the name of the selected study This command calls the dialog for setting up the results to be displayed in the tree ae ree Studies Bend of beam grb ow sE Bo P Solve Ee Me l Edit H E Fe a H E Lo T Material H Fe al Load fw Total Load O H Total Load O H Total Load OZ A Total Load magnitude 7 Applied Temperatures Displacement e H Displacement Ox Displacement O r A Displacement OZ F Displacement magnitude Reaction Force e H Reaction Force 0X H Reaction Force OY F Reaction Force DZ Copy Study Items Delete P Information Alt F1 fo Measure Parameters Hide Loads Restraints a Export F Reaction Force m
32. ng e strain energy e node response is C Body grb Study_0 Task Study_0 Task Study_0 e the field of the strain safety factor Factor ost Eauvaent Sess nr 1 8636E 008 distribution over the volume of me the structure 50 9029 4 OP ltd a RR S O OO NHH S Sill 1 3998E 008 723 3849 This data is normally enough for predicting the structure behavior and pee making decisions for optimizing aerate 16508600 geometrical shape of a part with the goal of insuring the main strength criteria of parts 4 7223E 007 Enter command or select element 82 Static Analysis Details of Static Analysis Steps Static Analysis of a model is performed in several stages STATIC ANALYSIS ALGORITM Listed are the elements required for conducting an analysis To run a static analysis complete the following Steps THREE DIMENTIONAL MODEL OF PART CREATING STUDY Analysis New Study command i Step 1 Creating three dimensional solid model of a part Before starting working in T FLEX Analysis system the user shall prepare a three dimensional solid model to be evaluated A solid model can be built in T FLEX CAD environment or imported from other systems Static analysis can be performed over one or multiple ko operations bodies ASSIGNING STUDY MATERIAL ASSIGNING MODEL MATERIAL Step 2 Creating Study A Study is erated by the command Textual Menu Keyboard Icon D
33. of equations of linear statics Calculation Type the algorithm used for solving equations Types of possible algorithms and their use are described in the section Settings of Linear Statics Processor Solution Found tells that system of equations was successfully calculated There is also auxiliary information in the brackets iter number of executed iteration if iterative method was used tol miscalculation of result after calculation The calculation steps are also visually displayed as a dynamically updating scale Additionally the time elapsed from the start of calculations is shown After finishing calculations the user must close the auxiliary window unless the auto close option is enabled Step 7 Analysis of static solution results After completing calculations a new Results folder appears in the studies tree By default this one displays the results defined on the Results tab of the Study parameters dialog Overall the user can access 38 solutions in the result of the static analysis sorted out into 6 groups 85 oo Displacements group Includes the following results A Component of displacement vector for a node of the finite element mesh along the OX axis of the global coordinate system A Component of displacement vector for a node of the finite element mesh along the OY axis of the global coordinate system A Component of displacement vector for a node of the finite element mes
34. pa TSS OOTA Original structure and its finite element discretization The structure that itself represents a distributed system of a complex geometrical shape is represented as a union of finite elements The finite elements that approximate the original structure are considered connected to each other at the corner points the nodes in each of which the three translational degrees of freedom are Introduction introduced for mechanical problems The external loads applied to the structure are converted to equivalent forces applied to the nodes of finite elements Restraints on the structure s motion fixings are also transferred to finite elements that model the original object Since the shape of each FE is defined in advance and its geometrical characteristics are known as well as the material properties therefore a system of linear algebraic equations SLAE can be written out for each FE that is used for modeling the structure describing displacements of FE nodes under the influence of forces applied at these nodes By writing out a system of equations for each finite element that is involved in approximating the original physical system we study those together and get a system of equations for the entire structure The order of this system of equations is equal to the product of the number of movable nodes in the structure and the number of degrees of freedom introduced in one node In T FLEX Analysis this usually amount
35. purpose is further available in the section Settings of Linear Statics Processor Most of the settings are selected by the processor automatically depending on the number of dimensions in the study being solved and imposed boundary conditions Clicking the OK button in the study parameters dialog CEDEISESI launches the process of building and solving systems of study 3agaya_o linear algebraic equations The stages of solving Calculation process equations and additional reference information are Caseig sar displayed in a special information pane Clicking the Close button in the information pane terminates Elapsed time 00 00 05 calculations Messages The Close this dialog box on solving complection Nodes 1725 flag will force automatic closing of the solution steps ESM ee monitoring window after finishing solving equations Arguments S058 Calculation Type iterated The flag Save Document on solving completion will Ei eno j j Pre Processing combined force automatic saving of calculation results and all Solution Found fiter 57 tol 0 000825895 changed data in the active document E E EN The following reference data is output in the information m Pee teen ean eet inoeninecen window T Close this dialog box on solving completion Nodes the number of nodes in the computational finite element mesh Elements the number of tetrahedras in the finite element mesh Arguments the number
36. the range 0 0 5 Model edge Mesh edge Minimum curvature Works together with Curvature ratio This sets the ultimate minimum size of a curve segment to which it can be divided This parameter is introduced for limiting the number of mesh elements this is because automatic subdivision of surfaces could go on indefinitely on some models such as a cone in order to meet the specified bending amount condition This parameter permits any values greater than zero Curve processing disabled Curve processing enabled Optimization options provide control over the process of generating an improved quality mesh When the generator creates the mesh it first calculates a preliminary mesh After that the program can apply certain manipulations to the obtained preliminary mesh in order to improve its quality Those manipulations are divided into two stages optimization which changes connectivity between mesh vertices and Smoothing which replaces mesh vertices Optimization can be either enabled or disabled Smoothing is driven by a number in the range 0 5 A greater number yields greater smoothing A high degree of smoothing will temper transitions in the mesh size One can distinguish the surface and the volume mesh optimization Preparing Finite Element Model for Analysis Preprocessor processes In most cases when those are unnecessary you can disable these options This will speed up the mesh generation process Not modifyin
37. the results which would affect all studies e 4 Main font sets the default font for the textual information Se ae aL Simplifications output in the visualizer window of the Postprocessor study E ae eee name result type etc f number of Elements is more 100000 Scale font sets the font of displaying numerical values on Strain State Window the color scale T Show window automatically HE greo eee Value tooltip control enables the mode in which a tooltip B pops up with the interpolated result value corresponding to D a See h ti th d th P t x d Show window automatically the ocation on the model in the Postprocessor window Pisce ae eaence aimed at by the mouse pointer cole Delay control allows specifying a time interval after which the tooltip pops up In the group Simplifications the user can specify the limit number of finite elements beyond which in the Post processor window the calculation results are shown only for corner nodes of quadratic finite elements and omitted for the mid side nodes this does not affect extreme values This mode allows the user to significantly expedite dowloading of results into the Postprocessor window for very large meshes more than 1000000 elements Options Show window automatically Hide window automatically in groups Deformed state control window and Time process control window allow us to control the view of
38. to them shapes of structures Buckling Analysis and also for modeling problems of cyclic loading which take into account fatigue phenomena Force Force is a type of loading used to specify a concentrated load and also for specifying a total magnitude of distributed load To specify the load Force use the command Keyboard Analysis Load Force After calling the command select the model elements for applying the load Use the following menu option Select Element for loading select a faces edges or vertices of the model being analyzed The selected objects are added to the list Also since with the help of Force the user can specify the total magnitude of linear surface load it 1s also necessary to define the way this load is distributed along the edge length over the face area In the window properties it 1s required to specify the load type e uniform e non uniform Force as a Total Magnitude of Uniformly Distributed Load When defining the Force as a total magnitude of uniformly distributed load it is required to specify the numeric value units and direction of its action 42 Preparing Finite Element Model for Analysis Preprocessor Force Parameters x Face 30 Distribution Uniform Y Uniform Load Direction Normal mt E Element I EE nA AAE Y E LCS Poo zt Reverse Direction Set as default Cancel Numeric value The numeric value is defined as a total equivale
39. upper level of liquid coincides in space with the coordinate Z 0 of local coordinate system determining direction of the load change To work with the local coordinate system use the options In a 3D scene the load Pressure is shown in the following way Specifying load Pressure 51 T FLEX Analysis User Manual Typical sequence of steps for defining the load Pressure Initiate command Pressure E l 2 Select face edge or a sequence of elements 3 Select load type uniform non uniform or hydrostatic 4 For uniformly distributed load specify a numeric value 5 For non uniformly distributed load specify the distribution law 6 For hydrostatic pressure specify density of liquid 7 Specify units 8 Specify direction 9 Complete the command Centrifugal Force 52 Rotation represents a loading type used for simulating a centrifugal force which arises upon uniform or uniformly accelerated rotation of an object For specifying the load Rotation use the command Keyboard After invoking this command select one or several solid bodies for applying the load With the help of automenu option select bodies of an analyzed model They will be added to the list Rotation always takes place about a certain axis thus it must be specified As an axis of rotation you can use an element of a 3D model edge axis of a cylindrical face etc or a specially constructed line for example a 3D pa
40. zA 2 y F7 ee arh t Radiator 4 T Material Load Restraint b a di Heat Flow LS Result ar Convection ot a a ag Thermal Power Report w Radiation Clear Study Commands for defining boundary conditions of thermal analysis When defining thermal loads you need to distinguish and appropriately use the two options of defining the Temperature load see Preprocessor Initial Temperature and Temperature The initial temperature is used for defining thermal loads at the initial zero moment of time for the transient thermal analysis only All thermal loads defined without the initial flag are considered constant invariable in both the steady state and transient thermal analysis Solving Before running calculations the user can specify the type of a thermal analysis study being solved the Parameters tab steady state or transient heat transfer and if necessary adjust algorithms for solving systems of equations on the Solve tab Analysis of thermal solution results The results of a thermal analysis are Temperature fields temperature distribution over the model s volume Thermal gradients by the X Y Z axes and the magnitude of the thermal gradient reflect on the degree of temperature changes by the respective axes of the coordinate system Resulting thermal flux by the X Y Z axes and the magnitude of the resulting thermal flux show the rate of thermal energy transfer determi
41. 0 0 0 3 Structure s Static Strength Assessment Strength Theories The ultimate safe stress state is when material properties undergo a qualitative change a transition from one mechanical state to another one For plastic materials the safe strain state is commonly considered as the condition of developing noticeable residual strain while for brittle ones a condition when a material begins to crack The ultimate state is not admissible for materials Therefore when performing strength analysis pursue the so called admissible state It corresponds to the load obtained by dividing the load of the ultimate strength state by a safety factor If the safety factors are equal in two stressed states than those are called equally fail safe To compare various strained states the simple tension compression is accepted as the universal measure with the principal stress O i the stress to be developed in a stretched specimen in order to make its state equally lt o Equivalent stress o equiv unsafe as a specified stress state The strength criterion is written out as o equiv Strength theories are hypotheses about criteria describing the conditions of a material reaching the ultimate strength state First strength theory In the first strength theory a material s ultimate strength refers to the maximum normal stress According to this theory the unsafe state occurs when one of the principal stresses reaches a safety thre
42. 5 m and the crosssection dimensions L SI b 0 05 m h 0 02 m After building the model let s create the Buckling Analysis study using the command Analysis New Study and generate a finite element mesh The beam material will be the default E 2 1 10 Pa v 0 28 Let s define the boundary conditions as follows The bottom face is fully restrained and the upper one is subjected to the distributed load in the amount of 1 N Finite element model of the beam for buckling analysis Using the command Analysis Solve we will evaluate the beam buckling First buckling mode of the beam The load ratio value came out equal to 69310 The analytical solution to determine the critical load appears as 2 p 14 2 Z EJ _ 6 9087 10 N crit uD T where E the Young s modulus J the moment of inertia the beam length u the length factor that depends on the support arrangements and the beam loading method In this case u 2 Therefore the solution accuracy is 0 3 120 Verification Examples Examples of Frequency Analysis Study Determining Natural Frequencies of Beam Vibration Given is a cantilevered beam of length L with a rectangular cross section of width b and height h L b Sought are the three natural frequencies of the beam Assume L 0 5 m b 0 05 m h 0 02 m The material properties are the Young s modulus 2 1 10 Pa the Poisson s ratio v 0 28 the density p 7800 8 Upon
43. Celsius Upon completing the commands of building the finite element mesh and defining thermal loads we get a calculations ready finite element model Convection Parameters Heat Power Parameters Extrusion 0 its Jwime2c Value 15 Temperature 25 Units Units Defining Heat Power load Defining Convection load Step 3 Running calculations and analyzing results We will start the thermal analysis by running the command Temperatures o Analysis Solve In the appearing dialog of the study s aaa properties set the Steady state option on the Parameters tab Use the Calculate using linear element mode on the pada Solve tab to speed up the calculations The list of calculation results is displayed in the Studies window and can be accessed by the context menu in the calculation results window The maximum temperature according to the heat and analysis results is 41 9 C at the PEENI convection temperature equal to 25 C We will then edit the convection temperature using the Edit command of the studies tree context menu setting the operational ambient temperature to ee its upper limit 55 C and then rerun calculations We will ne obtain the maximum temperature of the microchip equal to 71 9 a C The conclusion is the radiator does fulfill the required Temperature fields in the radiator under the temperature condition for the device in the entire specified range convection temperatur
44. Color scale setup below The scale is displayed in the left of the calculation results window Study Name This flag enables the display of the current study name in the calculation results window Result Type This flag enables the display of calculation type name The Number Format group provides the following controls Units Serves to define the measurement units meter inch millimeter to be used for displaying the result Format of values parameter sets the format of the scale numbers for the viewing convenience it can be decimal exponential or general mixed The general format represents values up to the 1000 in the decimal format VEET 3 E l imel T those greater than 1000 in the exponential format The Gi u A number of significant digits for the exponential format and Show trailing zeros the number of decimal digits for the decimal format are set i l faul in the provided field at the right Extra zeros can be Libero Sales able automatically discarded by disabling the flag show trailing zeros Color Scale Setup 72 The color scale settings dialog can be accessed from the parameters window of the calculation results the button Settings or from the context menu accessible in the calculation results window by clicking D Perform color scale settings in order to associate the desired colors with the obtained values The system does the initial setup automatically It evenly distributes
45. Cooling study is ready for defining calculation parameters Step 2 Defining parameters of transient analysis Set the Transient mode on the tab of the thermal analysis properties Define time analysis parameters the modeling time of 30 minutes the modeling step of 0 5 minutes Let s use the result from the previous steady state radiator evaluation as the initial model temperature Thermal Analysis Study Properties Thermal General Parameters Solve Results Steady state Transient Process time 30 H minute Time increment o s H minute Initial temperature Use preset temperature Default valie 2965 f Use heat task results Heating T Time 0 second Setting up study parameters for calculating cooling process transient heat transfer Step 3 Analyzing calculation results Let s run calculations and analyze the results Using the Time process bar we can determine that nearly complete cooling of the radiator will occur in approximately 26 minutes after turning the device off Temperature Time 1590 00 c Task Cooling i Wax 24 9009 24 9889 24 9887 24 9956 24 9004 24 9882 Min 24 9582 Device cooling calculation Temperatures distribution at 1590 seconds of the calculation time 115 Pykosoocmeo nonb30eamena T FLEX Ayanu3 VERIFICATION EXAMPLES In this chapter we review the results of solving several model s
46. EFINING LOADS AnalysislLoad command DEFINING RESTRAINTS Analysis Restraint command i Analysis New Study FEA To perform a static analysis when creating a study the user specifies its type Static Analysis in the command s properties window If there are multiple bodies in the scene then you need to select one or several contacting bodies for which a new study will be created Step 3 Defining material One of the required elements of SOLVING Analysis Solve command ANALYSING RESULTS STUDY Results Analysis Report i and other commands any solution is the study s material Detailed description of material defining methods for calculations is provided in the respective section of the preprocessor description Step 4 Creating mesh To perform Finite Element modeling you need to construct a finite element mesh By default the mesh construction command initiates automatically when creating a study The user can also create a mesh using the T FLEX Analysis command Analysis Mesh When creating a mesh the user defines various parameters of discretizing a solid state model The finite element mesh can significantly influence the quality of the obtained solution in the cases of complex spatial configuration of parts The finite element mesh generation parameters are reviewed in detail in the respective section of T FLEX Analysis preprocessor description Step 5 Applying boundary c
47. F show only Model Materials Variable Materials Set as default Cancel Pe 3 GM ET Pr f stu IE ae gt 4 Besides the standard T FLEX CAD material library a material from T FLEX Analysis database can be used for calculations Access to the Analysis material database from the current study 1s provided by the command Analysis Material or by the context menu of the studies tree displayed in the studies window ga S BRE DO MO INTS f 7 T FLEX Parametric CAD C Nprmepbi Body grb File Edit Construck Draw Operation Title Block Analysis Parameters Tools Customize view Window Help xy oa acHla F 70 _ Newsudy 1 f Bl pege ET Defaut ET T TEE Studies CE aa l Bo Mesh x if J Sues Bod oa z Ep Study 0 Load gt tg a Restraint F vf GF Mesh_O pales Thermal Load p F Sensor ia ie Result Hf a Solve lol Report lear Study i Export a Result Window ie a Show Study Elements ma ia Show Studies Window DL r Settings K x Y g E E ETF i stu IE H SMI Edit Study Material 14 Introduction Let s assign the material Steel AISI 1020 from the T FLEX Analysis materials database for the model under consideration Material Properties Operations From Operation Other Library Material ree ooe R Materias Allowable Tension a962 Aiton zi Plastic PTFE general Allowable Compression 399 526 Miimmt zi Yield Stress po Mimm
48. Plate Clamped Along the Contour We need to find the maximum deflection of a round plate of radius R and thickness h which is clamped fixed along the contour and is y loaded with a uniform pressure q distributed on the top face of the h plate a T Because of the symmetry in this study we will work with one quarter of the plate Assume the plate radius R 0 2 m thickness h 0 01 m and the pressure q 1000 kN m 2 After building the model we will create a study of the Static Analysis type using the command Analysis New Study and construct a finite element mesh We will leave the default plate material the Young s modulus E 2 1 10 Pa the Poisson s ratio v 0 28 Next we need to apply boundary conditions The side surface of the plate will be fully restrained whereas the free faces introduced after discarding of the plate are subjected to partial restraints in the normal to the faces direction because the points in the sections cannot have extra displacements in the normal direction due to the symmetry Pressure in the amount of 1000 kN m 2 is applied to the top face of the plate Finite element model of the plate with loads and restraints We then run the plate static analysis using the command Analysis Solve Displacements of plate points 117 Pykosoocmeo nonb30eamena T FLEX Axyanu3 The maximum deflection at the center of the plate comes out equal to 1 3244 mm There is an analytical solution to this
49. Radial Inches e Radial By Rotation Axis By Circle radians e By Cirle e By Rotation Axis su ASI Mahe bls Se nche A spherical coordinate system allows a Ai Restraint by Axes constraining mensions 1n Paid F e Radial Longitude radians diaa e Latitude Latitude radians Shown on the picture is an example of a partial restraint on a surface in a cylindrical coordinate system In this case partial restraints are defined in the circumferential direction whereas there are no restraints in the radial direction and along the rotation axis meaning that the revolution about the own axis is excluded for the shown body The symbolic notation for those restraints is special marks oriented in the respective directions 39 T FLEX Analysis User Manual Coordinate System Cylindrical ad cS ics oO Restraint by axes T Radial inches M By Circle radians O By Rotation 4xis inches The Partial Restraint command also provides another useful functionality The user can specify known displacements for the structure such as a known in advance strain in the structure For this specify the value of fixed displacement of a model element along some of the coordinate axes in the Partial Restraint command s properties window Static analisys will be performed with this condition Full Restraint Partial Restraint Note that a static solution is possible in this case without applying additional force
50. Study Elements cccccccccesssssssseesesseseeseseeesesseseeeeeeeeees 66 Specifics of Working witha Parametric Model crinnicinesiei iana EEA E A 67 EXPO a a E a a a a a a a e ade iaaadetes 67 Processing Results POStProcesSsSOr scsisesscaic cess scctssuscsanscssotenecescenascecetstesaaiseasctaedinesacavencaccubuceeasavaacucelaucsadstuescts 68 General Principles Of Workine with IRGSUITS 2550 aicics cas ies escalate eee las eee 68 Settings and Service Commands of Calculation Results Window ccccccccccccssceseeceeeeeeeeeeeeeeeeeeeeeeeeeeeeees 70 Customizing Calculation Results WindOW cccccccccssssscccccccceccececececceeeeeeeeeeeeeeaeeaeeeaeeeeeeeeeeeeeeeeeeeeeeeeeeeeseeeeeeeess 70 Color SCANS SEM onea E E Seq aa eaves O A TE ed AE bo I2 Use of Sensors for ANALYSIS OL RESIS oiadi e e T a T N N 75 ETS AULT REDOT S eiia la ett a lat ttl Sl lla ema atta 76 Repor Wc MNO ALCS a ratadcsceatdase tate dee ietaseaacea dos Gatetass baase des daetanse nace dus esacasreasak aso sana ss esate Se eas tea eas Renee rete 78 List Of Tacs for Gene raime REPONS serana 22s so aas sae dda ds so ate aes ok aaa aseptic 78 Example Of Interprenne aie CSU eia a E A dete RE E A EE EEEE 79 SOC ANAIS ISi a e a E A E A E E daaa 82 Details of StatiCuA Maly SIS SIEDS eren e A n A E A NA 83 Algorithm for Static Strength Evaluation Based on Modeling cccccceesesseesssesesesesssseseeseeeeeeseeeeseeeesteeeeaas 88 petuings or Linear an
51. Use large displacement Formulation Geometry nonlinearity Number of load steps id Update load direction with deflection Newton Raphson bg Maximum equilibrium iterations 0 001 100 cot te Method The option Account for stiffness change at large deflections should be activated in cases when at least one of the following assumptions of the linear analysis is violated 1 Resulting deformations are sufficiently small so the stiffness changes caused by the load can be ignored 2 In the process of applying the load boundary conditions do not change amplitude direction and distribution For example the linear analysis of the spiral like part subject to the load applied at the end edge gives an error of approximately 30 compared to the nonlinear analysis This difference in results arises due to small displacement assumption adopted in linear analysis Task Linear Task Nonlinear Displacement magnitude m Displacement magnitude m Displacement scale 1 00 Load factor 1 00 Displacement scale 1 00 1 24638 0 843329 0 936993 0 632497 psa 0 627605 2471585 7 0 318 attpaaa m r ES i Linear analysis Nonlinear analysis Static Analysis Controls in the group Geometric nonlinearity allow the user to customize the process of solution of geometrically nonlinear problems For solving such problems a time stepping nonlinear solver organizes the process of incremental
52. _ reaction force in the direction of the OX axis of the global coordinate system Xx F reaction force in the direction of the OY axis of the global coordinate system F _ reaction force in the direction of the OZ axis of the global coordinate system Reaction force absolute value the magnitude of the absolute value of the nodal reaction forces of the Z model defined for a node as F F F F where F x component F y 7 y component F_ z component of the reaction force for the i th node of the finite element mesh Total Load group displays the loads applied to a finite element model as the effective node responses This type of data represents reference information Temperature This result shows distribution of temperature field over the volume of the model Algorithm for Static Strength Evaluation Based on Modeling Once the study calculation is completed successfully you should analyze obtained results in order to make conclusions on probabilistic static strength of the structure In most cases three types of solution suffice displacements stresses and the strain safety factor A typical sequence of steps for validating the results of Finite Element modeling is as follows 1 Displacement Analysis In the studies tree use the context menu command Open or Open in new window to open the Displacement magnitude solution We can visually estimate the pattern and the ranges of the stress stra
53. ach quite large values and directly threaten structural integrity Therefore the critical state which immediately precedes rupture is considered inadmissible in real life conditions The threat of buckling is especially great in compressed zones for light thin wall structures such as slender rods plates and shells The buckling phenomenon exhibits various forms completely new forms of equilibrium appear known stable configurations deteriorate etc The buckling analysis module serves for conducting the so called initial buckling structural study The result of the study is a coefficient of the critical load under which the structure may spring into a new equilibrium state and the shape of the new equilibrium state corresponding to that load In such a case a situation is possible when the critical load under which buckling occurs could be much less than the load under which the maximum strength of the structure will be exceeded based on the linear static stressed state of the structure In other words the stresses in the structural material may not reach the ultimate values but deformations due to buckling may cause structural rupture Therefore the buckling condition can be formulated based on the critical load criterion as follows Actual loads applied to a structure must be less than the estimated critical load subject to an asserted safety factor F factual K lt F critical safety Having estimated the
54. additional explanation pee EE 5354 Maxinium Edge Length Relations e26 Minimum Angle between Edges psim Maximum Angle between Edges jisggraz Mininurn Radius Relations oz Mininun Tetrahedron Wolume ae Shell Elements Number of Shell Elements Maximum radius relations Reports the smallest ratio of the radii of the inscribed and circumscribed spheres of a tetrahedron Bee ee Maximum edge length relations is the characteristic referring to the mesh element that has the overall greatest ratio of its longest and shortest edges Maximum minimum angle between edges Reports the actually resulting maximum and minimum angles between edges of mesh elements 3 T FLEX Analysis User Manual Defining Restraints The location for specifying a restraint can be a face edge or vertex of the subject body The system supports three types of restraints full restraint partial restraint and contact A restraint is added to the active study and can be related only to elements of the body that is used in the active study To avoid a failure when solving you need to create enough restraints for the model for example one full restraint Full Restraint This type of boundary conditions locks all degrees of freedom for the selected object A full restraint can be applied to a face edge or vertex of the model To specify a full restraint use the command Keyboard Analysis Restraint Full lt 3MC gt To spec
55. agnitude El Strain EPI E E Normal Strain 02 Normal Strain O r F Normal Strain 02 xl Default Cancel Clear Sa PPearance hl ka Invoking command Customize results Dialog for customizing the results list There are several ways to access results for viewing 1 Double clicking Ce on the result s name in the studies tree opens the Postprocessor window with the selected result 2 Accessing the context menu by the right clicking z on the result selected in the studies tree and using the command Open or Open in new window T FLEX Analysis Postprocessor supports use of multiple windows Several windows with different results can be opened simultaneously as well as several windows with the same result 68 Studies Bend of beam grb El ea Study 0 S Body_o El Mesh_O FE Restraints 1 H E Loads 1 Be Results 11 E Displacement Ov Displacement magnituda Open Equivalent Stress Remove From tree Factor of safety by eq Normal Stress Oe Normal Stress O r Normal Stress DZ ADpPearance Processing Results Postprocessor Open in new window Context menu to open result To delete a result from the studies tree use the Remove from tree command of the context menu accessible by right clicking on the selected result in the studies tree The result will no longer be displayed in the studies tree you can however still add it bac
56. agnitude of load Specify the axis of moment A a oe Complete the command Thermal Loads This type of loading is used in the heat transfer problems Heat transfer is the process of transferring the heat from one region with higher temperature to the region with lower temperature 57 T FLEX Analysis User Manual Temperature 58 Temperature characterizes a thermal state of a body and determines how warm it is The load Temperature is used for defining invariant in time constant temperature of elements of the model in steady state and transient thermal analysis and also for defining temperature difference in the static analysis of structure s strength when solving the thermo elastic problems The load Initial temperature is used for defining initial temperature in transient thermal analysis This thermal load defines the temperatures of selected elements of the model at time equal to zero In the nodes of finite element mesh which do not belong to the selected elements of the model the initial temperature will be assigned the default value The default value is defined in the dialog window Study s parameters on the tab Parameters For specifying the load use the command Keyboard lt 3TT gt Analysis Thermal or Load Temperature Temperature can be applied to a model body a face edge or vertex For selecting elements of the model use the automenu option Select Element for loarding
57. al load Convection 61 T FLEX Analysis User Manual A typical sequence for specifying the load Convective heat transfer 1 Initialize the command Convection Cdl 2 Select a face 3 Specify the heat transfer coefficient and temperature of environment 4 Complete the command Radiation 62 Heated bodies emit the energy in the form of vibrations of electromagnetic field into the environment Thermal radiation hitting a certain body is partially reflected partially absorbed and also partially passes through a body For specifying Radiation use command Analysis Thermal lt 3TR gt S em Load Radiatiom Load Radiation is defined for faces of the model For selecting faces use the automenu option Select Element for loarding Selected elements are added to the list Se ee In the properties window of the load Radiation it is Common Load Parameters required to specify the following parameters Face 123 Boolean 12 Radiation 0 5 E e Radiation type radiation into space Absorption 0 2 o Emissivity Temperature 25 e Temperature of environment T lk e Units Kelvin K degrees of Celsius C Radiation to Space visibility degrees of Fahrenheit F e e Radiation viewfactor for a face In the 3D scene the load Radiation is shown in the following way Specifying thermal load Radiation Preparing Finite Element Model for Analysis Preprocessor A typical seq
58. angular acceleration in the command s properties window 4 Complete the command Acceleration Acceleration creates a uniform impact on any body with a mass This impact is uniformly distributed over the entire volume of the selected body Use of this type of loading allows for example simulating the load of the own weight under the force of gravity To specify the load Acceleration use the command Keyboard Analysis Load Acceleration 53 T FLEX Analysis User Manual 54 After invoking this command it is necessary to select the body or several bodies for applying the load With the help of automenu option Select Body Select All Solids select the bodies of an analyzed model They will be added to the list In the properties window specify Acceleration Parameters Magnitude of load Common Load Parameters Direction Element E 2 a 2 e Units m sec cm sec in sec e Direction of load Direction of load As a direction of acceleration the user can select the element of a 3D model or a vale Poo y certain radius vector specified in the selected by the Units mse l user local coordinate system 1f the local coordinate Gravity system is not specified the global coordinate system ae will be used by default ma e i _ caca By default in the local coordinate system the direction of load is set along the X axis To work with the local coordinate system use the o
59. arge mesh size With the reduction of the factor value the transition of sizes occurs in a lesser number of steps large leaps in the element size If the factor is equal 0 then a cell s size jumps to coarse without transition Normally the values near one are used most in practice 35 T FLEX Analysis User Manual 36 Refinement zone Vertex selected for mesh refinement Propagation factor 1 Propagation factor 0 5 Propagation factor 0 Refinement radius This parameter can be set only for model elements selected for local mesh refinement Refinement radius determines the size of the zone around the element within which the mesh is constructed with enhanced individually specified properties usually finer meshing The distance is counted from the element selected for refinement The absolute mesh size for each auxiliary element is specified separately In practice this capability can be used for achieving more accurate calculation results by the processor within approximately same calculation time using more coarse overall mesh for the entire model while a more elaborated mesh at critical points Curvature ratio This parameter enables automatic processing of curved surfaces and sets a limit on the minimum size of a mesh element during such processing The limitation is defined by the bending factor that is evaluated as the ratio of the depth d to the chord length h see the diagram The limitation can be specified in
60. artial Restraint command s properties window Static Analysis will be performed with this condition accounted for Note that a static solution is possible in this case without applying additional force loads In this way one can evaluate the stress developing in a strained structure when the quantitative values of the strain displacements are known Partial Restraint Parameters Ea Common Restraint Parameters Restraint by axes i Partial restraint E meters known displacements Iv meters Full restraint 5 Coordinate System B t meters Orthogonal My LCS E Rotation 1 radians OW Rotation radians Units SS Linear meters x _ Rotation 3 radians Angular radians Set as default Cancel Example of using known displacements A number of specialized commands is provided in T FLEX Analysis to define loads those allow defining main types of loads Force Pressure Centrifugal Force Acceleration Bearing Force Moment Detailed description of all types of loads is provided in the preprocessor description Note yet another functional capability of a static solution in T FLEX Analysis The user can define a structure s stress state analysis not only under various forces but also under thermal loads the Thermoelasticity Study As known structural materials develop linear strain under the thermal impact expand under heating and shrink under cooling Changes in a bo
61. astic Modulus 210000 Miimmt t2 Poisson s Ratio 0 28 Shear Modulus Birr 2 Thermal Expansion Joos Thermal Conductivity Joos Wii tran ded Units Unit System User Mass Units Grams Force Units Newtons Linear Units Milimeters Temperature Units Celsius Cancel By default the switch is set in the From Operation position This means that material properties are inherited from the operation s material If the switch is moved to the Other position then the input fields for the study s material properties become accessible One can use the button which calls the window with a set of predefined materials After selecting a material its properties are read and appear in the main dialog Located in the lower part of the dialog window are the fields for selecting units for main physical measures Constructing Mesh 32 For mesh manipulations use the command The mesh creation command can be automatically called after completing creation of the new study The command launches the mesh management procedure for the active study Depending on the existence of a mesh in the active study the system will either create a new or edit the existing mesh A mesh is created based on the operation selected at creation of the current active study Only one mesh can be created for one study Air Aluminum Allow 1060 Alloy Aluminum Allow 1345 Allow Aluminum Alloy 1350 Al
62. bing the face selected as the domain of application of a non uniform load a uniform grid of nodes is generated The density of grid 1s determined by the number of rows and columns in the distribution table The value of the function at a corresponding node of the grid is specified in the cells of the table 49 T FLEX Analysis User Manual Interpolation Since the values of the distribution function are known only at the grid points 1 e specified by the table it is necessary to extend definition of this function to any point on the face In the T FLEX Analysis there are two ways of defining the function from the known values bilinear interpolation linear dependence is constructed between the values at the grid points and spline construction Units For load Pressure applied to a face the following units are used N m lbf in kgf in Load direction As a direction of Pressure the user can select the normal to the loaded face the element of a 3D model or a certain radius vector specified in the selected by the user local coordinate system if the local coordinate system is not specified the global coordinate system will be used by default By default in the local coordinate system the direction of load is set along the X axis To work with the local coordinate system use options To specify the direction of the load Pressure with the help of a 3D model use the automenu option lt D gt Select direction To cancel s
63. bjects selected for defining Unit system acceleration amount direction local coordinate system Bearing force Cylindrical face Objects selected for defining Unit system force amount direction local coordinate system Torque Face Objects selected for defining Unit system moment amount axis local coordinate system 63 T FLEX Analysis User Manual Temperature Body face edge Magnitude of load units vertex Heat Flux Flux Magnitude of load units of load units a Power Body face edge a system Heat Power vertex Convection Face Heat transfer coefficient temperature of environment units Radiation Face Radiation type emissivity temperature of environment units radiation viewfactor of a face Editing Loads and Restraints To modify specified loads and restraints use the Edit command oa Circular plate quarter grb El E Study 0 I im Body_1 fH a Mesh_O a oO Dpape 3 A a a me tll Partial A Sa R ecreate E aS Results 4 available in the context menu on right clicking z a study element in the studies window or in the 3D Model window Further user actions of modifying loads or restraints are little different from the process of their creation In the properties window you can modify numerical parameters while the appropriate automenu options see above let you cancel selection and then specify new defining model elements Paste clv Paste Ctrl Copy Propert
64. bortion of computations Note also that defining loads properly is important for the initial buckling study to be correctly formulated In particular in certain loading cases the solution to the study may not have physical sense for example in the case of a rod being stretched with a tensile longitudinal force Correctly defined boundary conditions are signified by a positive value of the critical load coefficient resulting from the study Running calculations Before running calculations the PETE x user specifies computational algorithms and the number study study of buckling modes to be analyzed in the study AEE aee properties Solving system The following data is output into the information window when running calculations Elapsed time 00 00 19 Nodes the number of nodes in the computational finite needa element mesh lt Nodes 13502 Elements 6625 Elements the number of tetrahedra in the finite Arguments 40269 element mesh Calculation complete Arguments the number of equations used in the calculation Save Document on solving completion T Close this dialog box on solving completion Calculation complete this message signifies that the solution process is completed successfully Results The following are analysis results Load Factor the calculated value of the coefficient the product of which and the loads applied to the system makes the factual value of the c
65. buted load For specifying the load Pressure use the command Keyboard AnalysisiLondPressure gt After invoking this command it is required to select the model s elements for application of load With the help of automenu option lt E gt Select Element for loarding select the face or the edge of the analyzed model Selected elements will be added to the list Since with the help of option Pressure it 1s possible to define only distributed load it is required to define the type of this distribution along the edge length or over the face area In the properties window specify the load type e uniform e non uniform e hydrostatic Pressure as a Uniformly Distributed Load 48 When defining the Pressure as a uniformly distributed load it is necessary to specify the numeric value units and direction of its action Value The value is defined as a magnitude of load acting on a unit area of face or unit length of an edge Units For a load Pressure applied to a face the following units can be used N m Ibf in kgf cm For a load Pressure applied to an edge the following units can be used N m lbf in kgf cm Direction As a direction of Pressure the user can select the normal to the loaded face the element of a 3D model or a certain radius vector specified in the selected by the user local coordinate system 1f the Pressure Parameters Ea Common Load Parameters Distribution
66. cial notations boundary conditions With this visual representation the user can assess correctness of the data one specified Types of finite element models 22 Depending on geometric features of the analyzed structure in the T FLEX Analysis it is possible to construct any of three kinds of finite element models e tetrahedral finite element model e laminar finite element model e hybrid finite element model Let us consider the cases of using each type of the finite element meshes in detail Tetrahedral finite element model In this case to approximate geometry of the modeled part its representation by finite elements of tetrahedral shape is used Tetrahedral finite element mesh well approximates the arbitrarily complex shape of parts and provides satisfactory results of modeling physical problems for objects of arbitrary shape whose characteristic sizes along three space dimensions length width height are comparable with each other Most parts and joints of the standard mechanical and instrumental engineering equipment fall into this category Preparing Finite Element Model for Analysis Preprocessor Sb oe Ne CSE aes INL SALON LS So SVS bef R EA bs ANN N OAN FLD ase aes Ti e ma SAN iad TAVAN REA m ARNI AAZ ANT 4 2 A Typical mechanical engineering objects and their tetrahedral finite element models Laminar fini
67. completing the model let s create a study of the Frequency Analysis type Finite element model of the beam with restraints The analytical solution appears as 3 p 382 f E J 1 p o F2r l where f natural frequencies E the material Young s modulus J the moment of inertia p the material density F the area of the cross section the beam length k the factor that depends on the vibration mode k 1 875 k 4 694 k 7 855 The results are as follows T Flex arg o 121 Pykosoocmeo nonb30eamena T FLEX Avanu3 Determining the First Natural Frequency of a Round Plate Sought is the natural frequency of the first vibration mode of a round plate of radius R and thickness h clamped along the contour ib See Assume the plate radius equal to R 0 2 m the plate thickness h 0 01 m The material properties are the Young s modulus E 2 1 10 Pa the Poisson s ratio v 0 225 the density p 7800 X2 Due to the M symmetry we will consider the quarter of the plate and apply the appropriate boundary conditions a ee 2 ai es ra le Sa el a ee MaS ae Finite element model of the plate with restraints The value of the first natural frequency came out equal to 622 1 Hz First vibration mode The analytical solution appears as 3 p 452 10 21 D f z 7 6245 Hz R 2a p h l l E h where R the plate radius p the material density
68. conditions applied to the system To obtain a correct and trustworthy solution the user needs to imagine well the physical side of the phenomenon being analyzed in order to specify boundary conditions corresponding to real conditions affecting the product in its life cycle The result of solving a study will be fully determined by the composition and parameters of boundary conditions specified by the user A solution could be obtained that does not reflect on the essence of the physical phenomenon being analyzed if the user fails to interpret correctly the meaning of a mechanical or thermal load or restraint Note that the process of designating boundary conditions cannot be totally automated therefore the user is charged with the responsibility of correctly applying loads and restraints on the system from the prospective of the physically solvable problem Managing Studies Studies Management Commands 28 Study is a special system object uniting data and elements required for running a specific calculation of a model A study contains necessary settings of calculation parameters as well as information on the used objects solid bodies and or shells on the basis of which the finite element model is built loads restraints and finite element mesh After tudes Sphencal vessel of pressure gE completing calculations the study also contains solution results The type a a of a calculation to run is specified for a study static frequenc
69. cy of determining the numerical values of natural frequencies The frequency values achieved in a linear finite element calculation could be much greater than the values achieved by using more accurate methods You are recommended to use quadratic element calculations the default mode for quantitative evaluation of natural frequencies Diagonalization of mass matrix This mode enables the user to decrease the amount of memory required to solve the system of linear algebraic equations At the same time the accuracy of obtained results becomes slightly worse The Results tab defines the result types displayable in the studies tree after finishing calculations In the frequency analysis the user can assess only relative displacements either their absolute value or a value in the direction of the respective axes of the global coordinate system Study Properties Frequencies E Results Displacement General Calculation Pesults H e Relative Displacement 02 2 Relative Displacement O r 2 Relative Displacement OZ i A Relative Displacement magnitude M Save solving results in file Result List Use this command to set up items displayed in the studies tree Relative Displacement O Relative Displacement GY Relative Displacement OF Relative Displacement magnitude Default Cancel OK Cancel Help Thermal Analysis THERMAL ANALYSIS The thermal analysis module serves for solving heat tra
70. d Nonlinear Statics PrOCeSS Of cceseccattcetcsoiatescdaxeececsccdtvacead AR A E A sneer 89 Appendik RELEICHCES narepi a lacie E E oiesti assis iaeeiateet a esos 93 Properties OF SMMC UU aL VPAt Gill Seaan a sad buna teareawsbesledeatacenn inca ecco a a aa 93 Volume stress Sir ali Stale ata PON spades aaa ds eeaasidd a a a Mes e 95 Structure s Static Strength Assessment Strength Theories cccccccccccccccccceceeceeceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 97 Buckle A Maly Sis sscesssvsseusiatssccstedinavetes easa eaea A Ea aaa a a aa E e Eea aiaia 99 Details or Buckling Analysis Stepseenicsiriesaann aiea a e a ea aa eR 100 Algorithm for Buckling Analysis Based on Modeling cccccccccssseessseseeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeseeeeeeeeeees 101 Buckling Analysis Processor Setting Sonsini p e aR EEE EE 101 Freg ueney ANALYSIS niaaa E E E aAa 103 Details Of Frequency Analysis SIePs serene sna n re ete 104 Fireguency Analysis Processor Seting Sines als tasty clase ata E T eas T aa 105 Thermal Analysis anessan ania aaa a aa EE a 107 Detais or Thermal Analysis St pS sassone iio in REEE NEER REEE SA A N ROE EROE EEEE 107 Thermal Analysis Processor Setting Senu a T ER 109 Examples of Thermal Analysis Studlesnicca pa neice neater asd ee oar 111 Thermal Analysis of a Cooling Radiator Steady State nnnnnnnnnnnnnnnnneenenenreerrrersrrrrrrrrrrrrrrrrrrerrrssssssrrrrrrrreen 111 Calculating the Time of Heating up the Cool
71. deals with in real life Characteristics of material can be conditionally divided into two groups Characteristics of the first type are the ones affecting the display of three dimensional objects in a 3D window Characteristics of the second type are various physical parameters of material such as density elasticity modulus strength limit in tension etc The characteristics of the second type are necessary for carrying out calculations A part s response to loading depends on what material it is made of The program needs to know elastic properties of the material from which the part consists The program supports isotropic materials that is the materials whose properties are same in all directions By default material properties used for a study s calculations inherit from the subject operation s parameters Specifying an operation s material is described in the three dimensional modeling guidebook Additionally there is an alternative approach to specifying a study s material properties Specifying an individual study s material is done by the command 31 T FLEX Analysis User Manual After calling the command the dialog window appears Material Properties Operations Rotation 0 Steel Material Steel Density Joo otro 3 Allowable Tension fo tS Miimmt z Allowable Compression 5 Miimmt z Yield Stress mas Sf Mimmi z specific Heat pae lS Jig degree Material isotropic D El
72. des insufficient accuracy of calculating critical loads Critical load results are much greater by a factor of tens or hundreds of times via the calculation by linear finite elements rather than those achieved by more accurate methods It is strongly recommended to use only quadratic element calculations for quantitative evaluation of the critical loads the default mode The Results tab sets the displayable result types in the studies tree after finishing calculations Frequency Analysis FREQUENCY ANALYSIS The frequency analysis module serves for calculating natural frequencies resonant frequencies of a structure s vibrations and the respective vibration patterns The task of calculating natural frequencies and the respective vibration patterns arises in many practical cases of analyzing a structure s dynamical response under varying loads A most widespread situation is when it is necessary to assure at the design stage a low possibility of the mechanical phenomenon of the resonance under operating conditions As known the essence of the resonance is a significant increase in the magnitude of induced vibrations by dozens of times and even more at certain frequencies of an external disturbance the so called resonant frequencies In most cases the occurrence of resonance is an unwanted phenomenon from a product s safety viewpoint Probing a structure s natural properties against the possibility of a resonance in the operat
73. dy s dimensions cause strain and a stressed state T FLEX Analysis accounts for changing temperatures To define temperatures when accounting for transient temperature fields use the command Keyboard lt 3TT gt Analysis Thermal Load Temperature At same time you need to enable the Consider Thermoeffects option on the P as ticity tab of the static study parameters dialog in order to account for thermal loads in the static solution You will also need to define the temperature of zero strain which corresponds to the no stress state of the model and to define the working temperature field details are in the section Settings of Linear Statics Processor Static Analysis Step 6 Running calculations Once a finite element mesh is built for the model and boundary conditions are applied restraints and loads you can start the process or creating and solving linear algebraic equations of the static analysis Use the following command to start solving the active study Keyboard The selected study s calculation can be started from the context menu by clicking on the name of the selected study in the studies tree By default the Study parameters dialog of the static analysis opens automatically before calculations In this dialog the user can define the desired options and settings of the solution as well as specify the types of solution data displayable in the studies tree Detailed description of study settings
74. e a priority below Normal which would allow the user to simultaneously work in other Windows applications without much restriction Settings Processor Pastprocessor Document Temprorary directory Available 18968 Mb CA DOCUME 1 LOCALS 11Tempi A System Resource BelowNormal Size Mb 256 Use this option For set limitation on amount memory For iterative solver Solver thread priority I RAM limit M Display Study Properties dialog box before solving Close solver window on completion Cancel Help RAM limit allows the user to specify the size of RAM upon exceeding which the system would start using hard drive memory for solving equations that usually takes considerably more time Display study properties dialog box before solving when enabled this control turns on automatic launching of the study properties dialog box at initializing the Analysis Solve command for all studies the default setting 65 T FLEX Analysis User Manual Close solver window on completion this control enables the mode of automatic hiding the information window displaying the process of solving systems of equations in all Processor Postprocessor Document Visualizer Window Main Font Aral 3 E Scale Font Aral z E MW Value tooltip Delay studies By default this mode is not set On the Postprocessor tab the user can define global settings for viewing
75. e of 25 C of the device s operational temperatures The study is complete 4 0919E 001 Thermal Analysis Calculating the Time of Heating up the Cooling Radiator Transient Mode Let us estimate the time required for the device to reach a steady thermal state To do this let s run a transient thermal analysis of the microchip tradiator system Step 1 Creating study s copy We will create a copy of the original study in a steady state thermal analysis using the Copy command of the studies tree context menu On the General tab of the study s properties change the study name to Heating Study Properties Thermal General Parameters Solve Results Mame Heating Type Thermal g General Comment a El Step 2 Defining parameters of transient analysis On the Parameters tab of the thermal analysis properties set the Transient mode Define the time analysis parameters the modeling time of 30 minutes and the modeling step of 0 5 minutes We will use the uniform ambient temperature 25 C as the initial model temperature Study Properties Thermal General Parameters Solve Results Steady state Transient Process time 30 H second Time increment o s H second Initial temperature f Use preset temperature Default value 25 Use heat task results z Defining calculation parameters of transient heat analysis time and
76. e of signs is commonly used for stress tensor components a component is positive if it points in the positive direction of the respective coordinate axis of a facet with the positive external normal aligned with one of the coordinates Both the stress tensor and the strain tensor possess the symmetry property Tz T Try Tyo Tzy Tyy The symmetry conditions of the stress tensor are also referred to as paired sheer stresses condition the sheer stresses acting on two mutually perpendicular facets in the directions orthogonal to the edge in the intersection of those facets are equal in magnitude Due to these properties out of nine components of the stress tensor there are six independent ones Just like in the case of the strain the concept of principal stresses is introduced in a stress state O 2 07 2 O32 corresponding to principal strains related with the stress tensor components by the equation o Jo J20 J3 0 where Ox Ty Tyre CO Gal Os Tel Cy Ty J O0 0 0 Jo ae N AN J3 T O T a 3 o Ir o l Ia o yx VY J yx yY Z 2 Zy Z tmx ty Gz A cubic equation solution has three real roots 01 07 03 which are commonly ordered as follows O1 207 2 03 The principal stresses possess an important property the normal stresses on the principal Static Analysis direction oriented facets are highest among those on any other facets Also introduced is the concept of mean stress by the formula o 0 0 0 3
77. e of the function at a corresponding node of the grid is specified in the cells of the table Preparing Finite Element Model for Analysis Preprocessor Distribution Overall Force Interpolation Spline Value Units n Columns Rows Export Import visual Scale nO 5 Example of specifying distribution law for non uniform load Interpolation Since the values of the distribution function are known only at the grid points 1 e specified by the table it is necessary to extend definition of this function to an arbitrary point on the face In the T FLEX Analysis there are two ways of defining the function from the known values linear interpolation linear dependence is constructed between the values at the grid points and spline construction Figures show examples of non uniform load distributions obtained with the help of linear interpolation and spline construction Value 1 0389 0335565 Oat GaSe DESh5E2 OS63455 oara Oar O28d133 1900s 00ar79175 O0o48 i100 TRS DIOS Daril Distribution Example of non uniform load distribution function obtained by spline construction Overall Force 1 Interpolation Spline alue 1 A Units IN Columns 4 Rows 4 Export Import visual Scale 45 T FLEX Analysis User Manual Distribution Overall Force a Interpolation Linear value a Columns 4 Roms j Export Import
78. eat power 1 Initialize the command Heat power go 60 Preparing Finite Element Model for Analysis Preprocessor Select body face edge or a vertex Specify the magnitude of load a 2 Specify the units 5 Complete the command Convection Convective heat transfer is a process of transferring the heat between the surface of a solid body and external environment gas liquid Load Convection allows the user to specify the amount of heat emitted by the unit surface per unit of time when the temperature difference between the surface and external environment is one degree that is specify the heat transfer coefficient For specifying load Convection use the command Keyboard Analysis Thermal ane lt 3TC gt y i Load Convection Load Convection is defined for faces of the model For selecting faces use the automenu option Selected elements are added to the list In the properties window of the load Convection it 1s EIE EE necessary to specify the following parameters Common Load Parameters e heat transfer coefficient eee value fio 4 e Units W m C W cm C BTU sec in F cea wimeztc l e Temperature of external environment liquid or Temperature 25 gas Units Ic e Units Kelvin K degrees of Celsius C degrees ok i Set as default OF Cancel of Fahrenheit F aes Bae In the 3D scene the load Convection is shown in the following way Specifying therm
79. ecified by the user with the help of sensors Sensors can be created only for active problem of the finite element or dynamic analysis with the help of the command Keyboard lt 3MD gt Analysis Sensor In the properties window the sensor type is defined as a FEA point since the sensor is used for the problem of the finite element analysis For specifying a point where the sensor will be created use the automenu option This point can be a vertex on a profile path vertex on a body center of a curve edge middle point of an edge center of a sphere torus or a 3D node In the parameters dialog of the sensor there is a set of entry fields Operation Element Second operation Second element into which the names of the objects selected by the user are put 19 T FLEX Analysis User Manual Sensor Parameters Element Sensor _0 Property DISPLACEMENT O STRAIN EQUIV 0000993798 STRAIN s 0 0001 90245 Studies Bend of beam grb El ae Study _0 Elf Body 0 El Mesh_O FI Restraints 1 H E Loads 1 A Sensors 1 Sensor Type Fea Paint X Operation ce STRAIN 0 000100754 Jextrusion_0 ES Results xr Edit STRAIN 7 000124436 Element STRAIN YZ 0 000718181 vertex aO fq Delete STRAIN XZ O 000484669 Second Operation P Information Alt Fl Definition o ee Equivalent Strain Second Element Parameters Value 0 000993798 Appearance
80. election of direction use the option 2i lt U gt Cancel direction selection For a quick change of load direction to an opposite one the user can activate the flag Reverse direction EH Hydrostatic Pressure 50 Hydrostatic pressure or pressure of liquid is a special case of a non uniformly distributed load Pressure An example of such load is the liquid pressure exerted on walls of a vessel which changes with height as p p h where A is the height of a liquid column of density p When defining Pressure as a hydrostatic load it is necessary to specify the liquid density units and define the direction of load Preparing Finite Element Model for Analysis Preprocessor Pressure Parameters Ea Common Load Parameters Face _ Distribution Hydrostatic r Uniform Load Density J 1000 Units kgms Direction F Normal Element Les LES r Reverse Direction Set as default Cancel Direction of Load Change The load Hydrostatic Pressure acts along the normal to the loaded face It is required to specify direction of load change that is the direction along which the load is increased To specify direction of the load change it is required to select the local coordinate system The direction of load change increase will be determined by the direction opposite to the direction of the Z axis of the selected coordinate system The zero value of the load corresponding to an
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82. f this command displays the list of all studies existing in the current document The buttons for calling main commands are to the right of the list Edit Properties To quickly create similar studies of the same type and for the same model for example to compare solution results on different meshes or with different material one can use the study copying functionality Delete Salve Export Activate By default the option Copy mesh is turned on that is the study is copied with all elements contained in it except the results If this option is turned off the finite element mesh will not be copied 1 e for the considered studies the mesh will be common Material Copy Exit e peL To create a new study use the command After calling the command you can select the type for the study being created in the properties window Type Static Analysis Static Analysis At this stage all you can do is specifying the type of the new study Once a study ie za quency Analysis study is created its type can be changed only under the condition of clearing seal lar erma Analysts Express Analysis the study data including the loss of the calculation results A study is created based on one or several solid creating operations If the scene contains a single body it is selected automatically If there are more than one suitable objects in Thickness the scene then the user shall
83. g surface mesh while optimizing volume mesh allows optimizing the volume mesh so as not to affect the surface mesh obtained at the first stage of the generation Otherwise the mesh on the surface can be changed in the optimization This capability is useful in the cases when the user wants to maintain the mesh structure of the part s surface that was obtained as a result of adjusting grid settings yet still pursues optimization of the volume mesh Suppress small elements Enabling this flag tells the system what relative or absolute size minor model elements edges or faces can be ignored in the mesh calculation This capability shall be used in the cases when the model has such very small topological elements whose presence greatly slows down or even makes impossible calculating a valid mesh suitable for the Analysis purposes Small feature meshing The automatic mesh generator is fit with a special algorithm for an improved processing of small yet significant model features When enabling this mode you should also specify the maximum relative or absolute size of elements to be processed by this algorithm Smallest corner angle defines the admissible range of angle values between a mesh element s tetrahedron s edges The greatest triangle s angle is calculated automatically 180 a min At the same time note that angles outside this range could still be present due to other factors Maximum number of elements This parameter sets a lim
84. h along the OY axis of the global coordinate system Displacements absolute value the absolute value of the nodal displacements of the model defined for each node according to the formula A x a z where x y z displacement vector components for the 7 th node of the finite element mesh Group Stresses includes the following results O relative equivalent stresses evaluated from components of the stress tensor according to the formula o l ula o q Ja o o e z o o 6 T Pr T gt x normal stress in the direction of the OX axis of the global coordinate system y normal stress in the direction of the OY axis of the global coordinate system a Q qQ z normal stress in the direction of the OZ axis of the global coordinate system xy Shear stress acting in the direction of the OY axis of the global coordinate system on a plane with the normal vector parallel to the OX axis xz Shear stress acting in the direction of the OZ axis of the global coordinate system on a plane with the normal vector parallel to the OX axis yz Shear stress acting in the direction of the OZ axis of the global coordinate system on a plane with the normal vector parallel to the OY axis O 0 0 principal stresses 0 20 20 Stress intensity is defined in the following way O o O max o O 5 05 Os 86 Static Analysis Group Safety factor by stresses includes the fo
85. i Specific Heat oo Jig degree Material isotrope l Elastic Modulus 210000 Mitrom 2 neler beatae x Poisson s Ratio jos 7 Model Material Shear Modulus Miimmt t2 Cancel Thermal Expansion oom e Thermal Conductivity oom Wi iran Units Unit System User Mass Units Grams Force Units Newtons Linear Units Pillmeters Temperature Units Celsius OK Cancel Step 4 1 Applying Boundary Conditions Defining Restraints In order to successfully solve a physical problem in a finite element formulation in addition to creating a finite element mesh it is also necessary to correctly define the so called boundary conditions In statics their role is played by restraints and external loads applied to the system Three commands are provided in T FLEX Analysis for defining restraints Full Restraint Partial Restraint and Contact The Analysis Full Restraint command is used with the model s vertices faces and edges It asserts that a given element of the three dimensional body is fully fixed that 1s it maintains its original position and does not change location under the impact of loads applied to the system By using the command Analysis Full Restraint specify a fixed face of the model by selecting 15 T FLEX Analysis User Manual 16 Wj T FLEX Parametric CAD C pumeppr Body grb File Edit Construct Draw Operation Title Block Analysis Parameters Tools C
86. ies Li Upon finishing entering changes confirm your actions by clicking x Delete A 64 Preparing Finite Element Model for Analysis Preprocessor Customization and Utility Commands The user can define global settings of the T FLEX Analysis system by the Analysis Settings command Title Block Analysis Parameters New Study sT La I 3e we gita iy pp Studies ar A Mesh T Material Load Restraint Thermal Load Sensor if Result a Solve Report Clear Study g Export Result Window Ey Show Study Elements io Show Studies Window Customize plate qua The following parameters are defined on the Processor tab Temporary directory sets the path to the folder storing intermediate working data when solving systems of equations By default working files are stored in the folder defined by the Windows system variable TEMP or TMP If necessary the user can redefine this path System Resource group defines the following parameters Solver thread priority allows the user to define the system priority of the modules responsible for solving systems of equations The Windows operating system will distribute system resources in accordance to the specified priority giving preference to a higher priority For example if planning on prolonged solving of a large study using hard drive memory the user can specify in advanc
87. ify a restraint you need to select a model element Faces edges and vertices are available for selection Upon selecting an element the symbolic notation of the full restraint appears in the 3D window Symbolic notation of restraint Face selected for restraint Partial Restraint 38 When defining a partial restraint the user is offered to manually specify restraints on different degrees of freedom When using only partial restraints you need to ensure the sufficient number of restraints for fixing the model To specify a partial restraint use the command lt 3ML gt Analysis Restraint Partial Restraint To specify locations of a partial restraint select an edge face or vertex Next you need to define restraints by degrees of freedom The user can work in one of the three types of coordinate systems Cartesian cylindrical or spherical A local coordinate system is used for binding the coordinate system in question to the model It 1s worth noting that in the case when the user did not define the local coordinate system the partial constraints will be defined with respect to the global coordinate system Each coordinate system allows restraining displacements in three degrees of freedom An activated box item of the respective degree of freedom in the selected coordinate system means that displacements are fully constrained in this direction if the value is equal 0 or that a known displacement is specified
88. in plastic materials it is impossible to find the stress analogous to the tensile rheological resistance due to the specimen s flattening Brittle materials exhibit much better ability to resist compression strain rather then dilatational strain for those the compression rupture strain exceeds the ultimate tensile strength multifold Rupture of brittle materials under compression occurs due to cracking Volume Stress strain State at a Point The deformed state at a point of a deformable body is described by the symmetrical strain tensor TE ae a Y xy 5 Vz aha l E gi E pM 4 1 1 2 Naz 3 le Z where amp the longitudinal relative strain 7 Yzx gt Yxy Yyx gt Yzy Vyz the angular strain You can always specify the three orthogonal directions so that the sheer angles are all zeros while 95 T FLEX Analysis User Manual 96 elongations are 2 2 amp 3 The strains 2 3 in the directions for which sheer angles are absent are called principal strains at a point Together the nine stress components by three per each of the mutually perpendicular facets make up a physical entity called stress tensor at a point The tensor is represented by a symmetrical matrix Ox xy xz J T y Oy T Tx tz Oz yA where 0 0 0 the compression tension stress Tyz Tz Txy Tyy Tzy Tyz the sheer stress y The stress state tensor components in an infinitesimal block The following rul
89. in state of a structure It is necessary to analyze displacements in order to verify correctnes of applied loads and to assert correctness of the found solution as a result of solving systems of equations If the results of displacements analysis indicate that a solution to the study is found and the pattern of the structure s strain state matching the expected then you can proceed to the next step Displacement magnitude m Eguivalent Stress N m 2 1 7999E 005 a 3 0017E 006 1 3551E 005 2 2605E 006 1 7170E 005 9 0339E 006 1 5079E 006 4 5169E 006 7 5524E 005 0 0000E 000 2 6041E 003 _ 2 7029E 006 y she The diagram of absolute displacements and equivalent stresses 2 Stress Analysis Open the Equivalent Stress result One can visually assess the pattern of the calculated equivalent stress The stress gradients are illustrated by color transitions The color code scale displayed in the calculation results view window helps reading the approximate value of the displayed result If you point the mouse to the area of interest on the model then a tooltip will pop up 88 Static Analysis displaying the value of the evaluated measure interpolated by the nearest nodes around the pointer location The Equivalent stress result lets the user make the following conclusions a Determine at what locations and in which elements of the structure the largest stress develops b By comparing the maxima of the calculated stre
90. indow Help l lpeacala r p Default o0 viewing Results V Coloring IV Only external faces V Deformed state Relative scale Absolute scale 2404 76 T Animation E Negative deformations Frequency Limin M variable coloring Model Solids Boolean_14 r 20 T FLEX Parametric CAD C Mphmepbi Body grb ra X gt Bo ET iew Properties 5 body size LAAB l O e l gage OSE Fe Fle FOTIA 3 Xe Ape La IV Loads Restraints Loads Restraints JV Model Contour V Contours of all bodies Information Panel IV Study Name IV Result Type V Coloring Scale Numeric Values Units m Settings Numeric Format Scale setup This functionality is accessed by double clicking on the scale in the results viewer or by the Coloring properties command in the context menu of the calculation results viewing window The user has a range of opportunities for setting up display of numerical values One can use several predefined scale types and additionally a unique capability of setting up a flexible scale with an arbitrary color palette Also there is a possibility to specify the minimum and maximum values of the scale select the display of the logarithmic scale Dynamic result sampling T FLEX Analysis Postprocessor offers a convenient capability for sampling the result directly under the mouse
91. ing Radiator Transient Mode nnnnnnnnnneneeseeeeeeeennereeeeereesssen 113 Calculating Time of Cooling Down the Cooling Radiator Transient MOde cc ccceeesecceeeeeeeeeeeeeeeeeeeeees 114 Vericom EXAMDIES ssion tsas aaaea Naa a aaa 116 Examples or Solio Studies IM SACS oa n ads dc eee 116 Bending of a Cantilevered Beam under a Concentrated Lad cece ccecseeeeeesesseeeeeeseesseeeseeseeseseeeeeeeeeeeeeees 116 Static Analysis of a Round Plate Clamped Along the Contour ccccccccccccccccccccceceeceeeceeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 117 Analysis ot a Spherical Pressure Y CSSeliaiceesecshtie utenti siias camera atwetan tended dae luutesastad data watantendad ene luatoesatd ce 118 Examples ot Solyine Buckling Studies scccsis sees eit tee ae te 120 Buckling Analysis of a Compressed Straight Beam cccccccsssesseeseeessessseeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 120 Examples ot Frequency fal ySiS SCUGYy eraen naaie a a AA 121 Determining Natural Frequencies of Beam Vibration ccccccesesssseeseesseeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeseeeeeeeeeeeeeees 121 Determining the First Natural Frequency of a Round Plate 00 0 0 ccccccccccesseeseeeeseeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees 122 Introduction INTRODUCTION T FLEX Analysis is an environment for finite element calculations integrated with T FLEX CAD With the help of T FLEX Analysis a T FLEX CAD user can perform mathematical modeling of
92. ing range of external exciting frequencies at the design stage helps introducing changes in the structure that can alter the natural frequencies spectrum This could help avoid or significantly lower the possibility of resonance during operation Thus the vibro stability condition with respect to the natural frequencies criterion can be formulated as follows A structure s natural frequencies must fall outside the external exciting frequency range fel r3re where f the i th natural frequency of the structure Usually the greatest danger is presented by resonance at lower natural frequencies i lt 5 since that is where the most mechanical energy is concentrated fof the lowest and the highest frequencies of the known range of external exciting vibration aa per errr are EN a a ae ae eee ee ee ee wale we nes ie ge ae Oe ee ges Sage SS Se Nae Nae SE ew ara Ore ke Pe healed io ENSSE TE a 0 M 1 4 3 Variation in the amplitude magnification factor with respect to the natural frequency to the external exciting frequency ratio in a system with an insufficient damping wae By having evaluated natural frequencies of a structure s vibrations at the design stage you can optimize the structure with the goal of meeting the frequency vibro stability condition To increase natural frequencies you would need to add rigidity to the structure and or reduce its weight For example in the case of a slender object
93. initial temperature 113 T FLEX Analysis User Manual Step 3 Running calculations and analyzing results After the completion of calculations you can examine results at each time step To view such results we use a floating Time process bar that allows the user to quickly switch to the time instant of interest using a slider With the help of these tools we determine that a nearly complete heating of the radiator will occur after approximately 26 minutes Task Heating_0 Temperature C Time 1590 00 c 4 113500E 001 4 064385E 001 4 015786E 001 3 966671E 001 3 918072E 001 Result of thermal analysis at time 1590 sec 26 min Calculating Time of Cooling Down the Cooling Radiator Transient Mode 114 Now let s evaluate the time required for the device cooling radiator to cool down after an extended work Step 1 Creating study s copy Adjusting boundary conditions Let s create a copy of the original study of the steady state thermal analysis A Study Copy dialog appears when creating a copy of the study By clearing the flag Create Copy of Mesh the different studies will be made to use the same mesh This copying mode provides identity of finite element meshes two or more studies Let s call the new study Cooling Adjust the boundary conditions of the Cooling study For this delete the Heat power load from the Cooling study by the studies tree context menu command Delete Now the
94. isplay Zero Mark Serves to enable the display of the zero value mark on the color scale Always Show Maximum Value When this flag is enabled the maximum value string is displayed in the calculation results window Always Show Minimum Value When this flag is enabled the minimum value string is displayed in the calculation results window Processing Results Postprocessor ig Enampleorbrotudy O Jog 1 a d 7 Task Study_0 z AE 1 0838 ki unea E Logarithmic g Factor of safety by equivalent stress ee ere Displ t scale 24 95 C automaticaly 4 03043E 007 oE ea a value 5 007 1 37973 Minimum 1 49535 4 1 QOOOUOO00E 000 automatically 2 69399 1 62066 f value E 1 75647 1 505345452E 000 P Absolute value 1 90365 Colour Spectrum 2 06318 Scheme standard Save 2 23607 4 2 246031 76E 000 Iv Gradient Iv Reverse Load 2 40545 Threshold level rt a 2 62653 3 35114264E 000 Level 2i po SS 2 84663 Legend S 5 00000000E 000 W Display minimum on top Eat 4 hax 4 A4499901E 002 M Display marks 3 62359 IM Number of marks z 3 92758 I Display Zero Mark 4 2567 T Show maximum always 4 6134 T Show minimum always 5M Default Cancel Apply Setting the range of scale values for displaying results Use of Sensors for Analysis of Results In the T FLEX Analysis there is a possibility to probe the results of finite element analysis in a certain point sp
95. itation on the total number of mesh elements This functionality 1s provided to prevent accidental creation of a too large number of mesh nodes which might significantly slow down both generation of the mesh itself and the following solving If the number of elements exceeds the specified limit while generating the mesh then the system outputs the appropriate message and terminates mesh generation In such a case to obtain a mesh with the specified number of elements use more relaxed settings On the View tab one can specify the type of mesh rendering The surface mesh Mesh Parameters View helps assess most of the main properties of the obtained mesh In this way the mesh ea portions in the interior of the model s volume are not shown helping speedy system oe Volume operation when rotating the 3D scene The volume mesh rendering shows the entire mesh including its portions within the interior of the model s volume In this mode the system may experience a slowdown when rotating the 3D scene In such a case it would be best to use the wireframe mode for the 3D scene Mesh Parameters Ea Mesh Parameters View Information On the Information tab you can get information about certain properties of the obtained mesh the total number of vertices the number of finite elements etc All those parameters help Number of Vertices fisso assisting the quality of the resulting mesh generation Some of e the parameters require
96. its wimmz gt e Units W m W cm BTU s in Negative value of the heat flow signifies that through the Bj Sets deer Cancel specified face the body looses the energy In the 3D scene Heat flow is shown in the following way Specifying thermal load Heat flow 1 Initialize the command Heat flow L 2 Select a face 3 Specify the magnitude of load 59 T FLEX Analysis User Manual 4 Specify units 5 Complete the command Heat Power Load Heat power allows the user to define e volume power of thermal energy sources e amount of heat transferred through an arbitrary surface per unit of time called a power of heat flow heat power For specifying the load use the command Keyboard Analysis Thermal Load Thermal ie lt 3TP gt one 4 com gt Power Heat power can be applied to a body face edge or a vertex of a model For selecting elements of model use the automenu option Select Element for loarding Selected elements are added to the list Heat Parer Paramete Common Load Parameters In the properties window specify Face 122 Boolean e Magnitude of load e Units W BTU sec The negative value of this thermal load signifies that a body T Set as default Cancel looses the energy z In the 3D scene Heat power is shown in the following way Specifying thermal load Heat power A typical sequence of steps for specifying the load H
97. k to the tree using the above mentioned command Results You do not need to rerun study calculations when adding deleting results in the list To actually delete all results thus making the study unsolved use the command Clear Study accessible for the active study from the main menu or command Clear accessible from the context menu by right clicking o on the name of the selected study in the studies tree Studies Bend of beam grb ow a m Boc P Solve eti Mes H E Loa Te Material Copy Study Items Po Delete P Information Alt F1 fo Measure Parameters Hide Loads Restraints a Export Report a E esults Appearance ba hy E T FLEX T FLEX Analysis 11 Analysis Examples Ya Title Block Analysis Parameters Tools Customize is E Mew Study i a Studies B A e Te Material Load T Restraint H Thermal Load Sensor ie Result a Solve Report g Export l Result Window a Show Study Elements E Show Studies window Settings Invoking command for deleting all calculation results Results of a study s calculation and meshes can be stored together with the model in a grb file The user shall be aware however that storing those data increases the file size considerably If you need to achieve a minimum file size we recommend clearing calculation results in all studies befo
98. lculations will run faster and the finite element mesh can be created easier To correctly apply loads it is sometimes necessary to create special spot faces at some locations on large faces Step 2 Creating Study 10 Once a three dimensional model of the part is built in T FLEX CAD 3D or imported into the system you can proceed to preparing the finite element model Any type of calculations in T FLEX Analysis begins with creating a Study using the New Study command in the Analysis menu of T FLEX CAD lt Analysis New Study FEA Study When creating a study the user defines its type Static Analysis Frequency Analysis Buckling Analysis Thermal Analysis Additionally if more than one solid body is present in the scene then you need to specify for which body in the scene you are creating the study Let s create a study of the type Static analysis for our model part Introduction f 7 T FLEX Parametric CAD C Nprmepbi Body grb File Edit Construck Draw Operation Title Block Analysis Parameters Tools Customize view Window Help l paeaecd a 0 HIBS a Default 0 gt A oO Tee Properties wal _ ig Body ea Mesh v gt Material Load k lt lt Restraint Type Static Analysis 4 Thermal Load b c ere ae Study Elements a Enei i Body O Result x7 p Sole Report Gear Study re Export Result Window p a Show Study Eleme
99. llowing results Safety factor by equivalent stresses represents the ratio of admissible for a given structural material stresses lo to the equivalent stresses gela O eg Safety factor by shear stresses is evaluated as K o T a O O tro 2 gt max p T iak Safety factor by normal stresses is evaluated as gaa n O A material s safe stress is defined in the material properties in the standard T FLEX CAD library or in the appropriate field of the study s materials library The yield limit is accepted as the safe stress for plastic materials Group Deformation includes the following results E relative equivalent strains expressed in terms of components of the strain tensor by the formula aaa E 8 ry tHe FV a 2 4 relative normal strain in the direction of the OX axis of the global coordinate system E relative normal strain in the direction of the OY axis of the global coordinate system relative normal strain in the direction of the OZ axis of the global coordinate system Yx Shear strain in the OXY plane Y shear strain in the OXZ plane Yz shear strain in the OYZ plane E E E principal strains 2 2 amp Strain Energy Density The result reflects volume distribution of strain energy over the model 8 T FLEX Analysis User Manual Group Reactions The result reflects forces building up in the supporting fixed nodes of the finite element model F
100. loading of structure and gives the solution of the linearized system of equations at each step for the current increment of the load vector formed for a specific loading Number of load steps This option allows the user to set the number of steps during which the load will be changing from zero to a specified value Theoretically all solutions can be found within one step for total value of acting load However there arises the possibility of non uniqueness of solution and moreover the found solution may not have physical meaning In such cases it is reasonable to specify the load incrementally and obtain nonlinear solution for each increment From the computational point of view it is often efficient because the nonlinear effects will be getting smaller at each step If the increments of load are sufficiently small in magnitude each incremental solution can be found within one step with a high degree of accuracy By default the number of steps 1s set to 10 Update load direction allows the user to account for change in the load vector while applying the loading according to the deformed geometry of the model Solution method By default the Newton Raphson method of solving the system of nonlinear equations is used At each step of load application the system of the linear algebraic equations is being solved until the relative error between two consecutive solutions does not become smaller than the prescribed tolerance If the number of i
101. loads In this way one can evaluate the stress developing in a strained structure when the quantitative values of the strain displacements are known A typical order of steps for defining partial restraints is as follows T Initiate the Partial Restraint command EN 1 2 Select element to fix 3 Select LCS 4 5 Complete the command Contact 40 Mark the necessary limits for displacements by the axes and define their values Contact restraints are needed in studies of contacting bodies To define a contact use the command Keyboard Analysis Restraint Contact To define a contact you need to select the contacting faces of two bodies Next select one of four contact types Rigid Contact No Contact Touch Hard Wall The contact type Rigid Contact is used in the case when it is necessary to bond the contacting surfaces of the bodies The bodies are considered as bonded in this case so that relocations of a face in one body Contact Parameters Common Contact Parameters Faces of Second pahe 47 Extrusion 36 Faces of First Solid pahe 46 Imprint 39 Contact Type Touch se Rigid Contact Mo Contact he Touch Hard Wall Set as default Cancel Preparing Finite Element Model for Analysis Preprocessor result in relocations of the other body faces without any restrictions If the bodies are made of materials with different physical characteristic
102. loy Aluminum Allowi2014 Allor Aluminum Alloyvi2018 Alloy Aluminum Allowi2024 Alloy Aluminum AlloyiS003 Alloy Aluminum Alloyi6o0e Alloy Aluminum Allow F079 Alloy Brass T Model Material l Cancel Preparing Finite Element Model for Analysis Preprocessor When creating a mesh one can select model elements to obtain local zones of refined mesh This is done with the purpose of getting more accurate calculation results at the critical spots of the model The user can select the elements for improving mesh with the help of the following automenu options Select Elements to refine Mesh Mo gt xnHo BplOupats 3D y3iIbl BepIIMHbI p Opa n rpaHnu 5 Within the reach of the Refinement radius see below around the selected element the size of mesh elements will be equal to the size specified in the mesh parameters for the selected refinement element Element selected for mesh refinement Refinement area limited by the radius At the mesh calculation time the system displays a tool window that tracks the progress of the generation process The window has a Cancel button that allows terminating the mesh calculation process Messages Face meshing OK Smoothing surface mesh OK Analysis of surface mesh intersections 0K Creating volume mesh ial Cancel As the parametric model changes the mesh may require an update The system can automatically update the mesh if the respective setting is
103. ls for example low carbon steel Yield limit or Further elongation of the specimen for example for low carbon steels occurs practically with no increase in the load This phenomenon is called plastic flow and the horizontal part of the diagram immediately to the right from the bend point is called the plastic flow range In many structural materials the plastic flow range is not so prominently visible as in low carbon steels The notion of the conditional yield limit is introduced for such materials this is the stress corresponding to the residual plastic strain equal to s Usually s 0 2 The Yield Limit for plastic materials is selected as the strength criterion the maximum safe stress o Reaching stresses corresponding to the yield limit causes irreversible plastic strains in the structure thus breaking its viability and is thus an inadmissible behavior from the safety viewpoint The ultimate strength o rheological resistance is the stress upon exceeding which the material rupture occurs Upon an increase in the loads there is a moment after which more strain builds up in the specimen without an increase or even under a reduction in the load up to the rupture The Poisson s ratio u characterizes transverse strain developing in a stretching specimen In the elastic zone the strain in the transverse direction is l where the strain in the longitudinal direction u the Poisson s ratio For i
104. made in the mesh parameters Start the mesh update command manually from the context menu by right clicking the mesh in the studies window 33 T FLEX Analysis User Manual Mesh Parameters Settings for the mesh being generated can be made either in the properties window or in the identical parameters dialog Mesh Parameters E Mesh Parameters View Information Type of Generated Mesh Tetrahedron 10 nodes Mesh size Relative 0 05 Radius of local 5 refinement Refresh Manual Global Size Propagation Factor 0 1 M Global Curvature Size 0 0 5 0 15 Minimum Curvature Size Relative o 01 I Optimize Surface Mesh Surface Mesh Smoothing 0 5 I Optimize Volume Mesh T Do not Modify Surface Mesh while Optimizing Volume Mesh Suppress Small Elements Relative o 0001 M Small Feature Meshing JRelative 0 0125 I K T Smallest Corner Angle 1s Largest Corner Angle 165 000000 Maximum Number of Elements 1000000 Delay Mesh Generation Cancel There are two versions of finite elements used in the T FLEX Analysis straight edged and curvilinear The straight edged finite element has nodes only at vertices while the curvilinear element has intermediate nodes at the middle points of the edges see the picture Thus tetrahedrons contain 4 or 10 nodes and triangles 3 Set as default or 6 nodes 3 node straight edged triangular
105. mark Find Sortings Colors Use active View Filter Appearance Moye to Folder a5 GM ET Pr f stu iE Selected Boolean_14 File Edit Construct Draw Operation Title Block Analysis Parameters Tools View Window Help O Z5UA Bo D lL 6 l ORG O 20 780 OBO B FFE a Be aexs O lel Es 4 LI x X F ka a 4 e amp S O MOS The operation s properties dialog lets you select a material from the standard T FLEX CAD material library If necessary the user can add to the standard T FLEX CAD materials database one s own materials and modify properties of any materials in this library For detailed information on handling materials in T FLEX CAD refer to T FLEX CAD documentation the book Three Dimensional Modeling Materials Chapter 13 T FLEX Analysis User Manual 4 T FLEX Parametric CAD C0 puneppr Body grb File Edit Construct Draw Operation Title Block Analysis Parameters Tools Customize View Window Help x oa acHla 670 4l y 2u AA AlO L 6 Bl ORGO 8 2 a Default H oO z nat 0 o mE aE F Ae e e e a Studies EE i X TA Studies Body grb 2 Edy Study_0 At ie s9 A H Mesh_O Body Properties x Mame Body _0 Level Jo Layer Default Hide E Jo 5 T view as wireframe Attributes are Set l Mesh Density Color ii an Default Rough Smooth Material Name Materialo Z
106. ment of the specified magnitude distributed over the selected face Location of load application face Axis of moment To specify Torque use the command Keyboard You can use faces as the location of the load application To select faces use the automenu option ol lt F gt Select Face 56 Preparing Finite Element Model for Analysis Preprocessor Selected faces are entered in the list In the properties window specify e The magnitude of load i ee Units N m kegf cm Ibf in Common Load Parameters e The axis of torque Face Deruzin Torque 1 Units M m na The direction of the torque axis or axis of rotation defines the direction of load according to a right hand rule As a direction of axis of rotation the user can select an element of Axis a 3D model edge axis of a cylindrical face etc or a _ E 9 6 3D Fath specially constructed line for example a 3D path Bjo Cancel constructed by two 3D nodes or one of the axes of the local coordinate system To select the axis of rotation use the automenu option lt A gt Select axis of rotation To cancel selection of axis rotation use the option s lt C gt Cancel axis selection In the 3D scene the load Torque is shown in the following way Specifying load Torque A typical sequence of steps for specifying the load Torque Initialize the command Torque Ti Select loaded faces of body Specify m
107. mesh can be displayed in the 3D window A surface mesh is automatically displayed after finishing the generation process When the mesh is displayed the model is not shown If you need to work with the model for example to define a restraint on a model s face the system automatically hides the mesh To view the mesh again E eee one can use the Show Mesh command This command is available in Parameters the context menu upon selecting the Mesh element in the studies Copy Properties p Delete A i f E Update window This menu also contains commands for switching between the visibility surface and volume mesh views The commands are Volume Mesh and Edit Geometry Surface Mesh Show Mesh Bookmark Specifics of Working with a Parametric Model A T FLEX CAD model is usually a parametric one You can get full advantage of a parametric model in an analysis All study elements loads restraints mesh related to the model can be automatically recalculated as a result of parametric modifications of the three dimensional model and you will not have to define them anew It could be sometimes more convenient to manually update certain study elements that require significant computational resources for example meshes To update any element of the study you will need to select the command Update in the context menu invoked by pressing g on an element of the study If a parent element disappears for
108. must be given using command Temperature in heat loads Temperature fields group Use heat bask results o second Uniform temperature the value of a uniform temperature field is specified in the chosen units which affects all studied bodies Use preset temperature thermal loads are included in the static analysis that were defined by the command Analysis Thermal Load Temperature Use heat task results available solution of the thermal analysis study is used for defining the thermal loading In the drop down list select the name of the solved thermal analysis study and if necessary the time instant to which the solution pertains Please note that certain conditions are to be met for using thermal analysis results as the initial temperature conditions coe rob 1 Identity condition of finite element meshes in static and thermal analyses The simplest way of achieving such identity is the use of the Copy command available in the context menu The sequence of steps can be for example as follows a Create a study of the type Thermal Analysis generate a mesh define boundary conditions and run b Create a study copy using the Copy command c On the tab General in the study properties dialog changed the study type to Static Analysis As aresult we have two studies of different types but with identical finite element meshes 2 The Calculate using linear element property on the
109. n Title Block Analysis Parameters Tools Customize View Window Help lpeaeadla F o AZUAAS H O L 6 ol g RgO a Default 0 E Pal o z Ekke oS ealro ad x x Studies O Solving Linear Static ze EE Study Study _0 Elf Body_o Hs Meshi Ese Restrain Gy Loads Calculation process Calculating strain Elapsed time 00 00 09 Messages Modes 10473 Elements 5140 Arguments 28653 Calculation Type iterated Pre Processing combined Ol HHS 5l Solution Found fiter 45 tol o 000909725 Calculation complete I Save Document on solving completion T Close this dialog box on solving completion Clase Step 6 Analyzing Calculation Results Calculation results are displayed in the studies tree Access to results is provided from the context menu for the study selected in the studies tree by the Open or Open in new window command as well as by Ce Results are visualized in a separate 3D window of T FLEX CAD Several windows with the results from the same or different studies can be opened simultaneously The user has an access to all zooming and panning commands working on the meshed model with the applied calculation results just like those used with three dimensional models in T FLEX CAD Additionally there is a set of specialized commands and options providing various tools for processing calculation results Let us briefly mention the most important
110. n defining the default contact as Rigid Contact helps avoid manual definition of the contact type for all surfaces in contact Default contact parameters can be redefined with the help of the Contact command The dependency of a model behavior on various contact types can iis be illustrated with the following example Two beams are kept together using a contact restraint with one end fixed and a distributed force acting normal on the top and side surfaces of the first beam If the Rigid Contact type is used then the combined beam is deformed as a single solid In the case when the Touch contact is used one can see that the top beam makes the lower one deformed and at the same time slides along it When using No Contact one can observe penetration of the top beam into the lower one which shall be avoided when designing assembly models Contact type no contact 41 T FLEX Analysis User Manual A typical order of steps for defining the contact restraints is as follows Initiate the Contact command a Select contacting faces of the first body Select contacting faces of the second body Define the contact type Og a ly Complete the command Defining Loads Mechanical Loads This type of loads is used when modeling the problems of linear and nonlinear static analysis of structures strength Static Analysis when calculating the magnitude of critical buckling loads and corresponding
111. nalysis problem stationary steady state mode or non stationary thermal conduction transient process For non stationary thermal conduction it is necessary to specify a process duration Total process time time step and initial temperature 109 T FLEX Analysis User Manual In the thermal analysis controls Initial temperature Use preset temperature allow the user to define as an initial temperature e initial temperature prescribed with the help of the command Analysis Thermal Load Tempera ture e the default value of temperature at those finite element nodes where the initial temperature was not defined by the user The Use heat task results control allows defining the initial temperature by the results of an earlier conducted thermal analysis This dialog item becomes accessible to the user if there are earlier conducted thermal studies present in the model In the drop down list select the name of a solved thermal analysis study and if necessary the time instant to which the solution pertains Please note that certain conditions are to be met for using thermal analysis results as the initial temperature conditions Study Properties Thermal Ea General Parameters Solve Results Steady state i Transient Process time 100 second Time increment 1 second Initial temperature Use preset temperature Default value 296 Use heat task results
112. ndustry known by the acronym CAE Computer Aided Engineering T FLEX Analysis User Manual Technical Requirements Computer Requirements Mathematical modeling of physical phenomena belongs to the class of the resource intensive problems that require serious computational resources That is why for efficient use of the finite element modeling system it is recommended to use the most powerful computers accessible to the user Moreover increase in the dimensionality of the solved problem can be achieved by using 64 bit operating systems T FLEX Analysis is available in two versions depending on the edition of the Windows operating system 1 T FLEX Analysis for Windows 32 bit standard Windows for example for computers Pentium III or IV The distinctive feature of the 32 bit operating systems is the existence of physical bound on the maximum volume of addressed information about 2 GB which limits capabilities needed for analysis of systems with large number of finite elements 2 T FLEX Analysis for Windows 64 bit Windows XP 64 bit Windows Vista 64 bit This system works on the processors that support 64 bit instructions for example Intel Pentium D Intel Core2Duo AMD 64 and others Operating systems with digit capacity 64 bit allow the user to address significantly larger volumes of information and solve the problems of higher dimensionality Recommended computer parameters for efficient professional work with T FLEX Anal
113. near models Usually a finer division yields better results in terms of accuracy Nevertheless remember that approximating a model by a large number of small finite elements inevitably leads to a high order system of algebraic equations which could adversely affect the speed of calculations Quality of a finite element model can be assessed by subsequently solving several studies with ever increasing degree of discretization If the solution such as maximum displacements and stresses no longer shows significant difference on a denser mesh then to a great certainty one can regard it as an optimal discretization level so that a higher rate of discretization is unjustified Relative size of 0 2 Relative size of 0 05 26 Preparing Finite Element Model for Analysis Preprocessor In many cases consider the estimated minimum level of a body s division as that delivering two to three layers of finite elements in the direction of applying loads and anticipated displacements Additionally the mesh generator provides means for creating user imposed mesh refinement in the areas of the model with sharp variations in the curvature where one would expect high gradients of the sought values stresses for example Thus one should pay much attention to the meshed model being generated for a finite element model watching that the finite element mesh corresponded to the model geometry and had a satisfactory quality from the viewpoint of in
114. ned from the solution to the thermal analysis study Magnitudes of the thermal temperature gradient and the resulting heat flux are determined as the square root of the sum of the squares of the respective coordinate projected components Besides the mentioned results the following reference data can be displayed in the postprocessor window e Prescribed thermal flux corresponds to the specified initial parameters of thermal loads e Prescribed temperature constant thermal loads applied to the model e Initial temperature the initial temperature field applied to the model for the transient thermal analysis The methods for analyzing results of thermal analysis accepted in the T FLEX Analysis Postprocessor are in general similar to the methods of examining results in other analysis modules Let us mention some specific Postprocessor tools which can be used for analyzing results of transient heat transfer Solving a transient heat transfer study results in a large set of data whose total number is equal to the number of time steps specified by the user T FLEX Analysis provides the user with a convenient visual interface for managing the entire array of data resulting from calculations For this purpose a Time process dialog panel can be called from the results viewing window s context menu that can be used by the user to quickly switch to the desired result on the time scale Thermal Analysis T FLEX CAD Ax Ht File
115. ned the sphere inner surface displacement of 1 4070 mm The analytical solution appears as 1 p 737 U A r 1 4063 mm r P P 3o p P P E E v hie A Ey Be a a 2u4 32 ae Au ee The solution error in displacements amounts to 0 05 Besides that it is possible to estimate the error in the stress solution The stressed state problem of a spherical vessel 1s formulated in spherical coordinates The stress expressions are as follows r3P R P P P rP RP P P 1 0 3 1 0 l 0 1 2 1 0 o o t R _ r3 R _ r gt t R _ 73 The equivalent stresses are found by the formula Ore P F P 0 P 2 0 p o p The equivalent stresses on the inner surface of the sphere are o 7 1148 MPa i 3 7p P 7 a oo a In T Flex Analysis the magnitude of such stresses is r 1 14976 10 yi J The solution error in stresses amounts to 0 18 119 Pykosoocmeo nonb30eamena T FLEX Ayanu3 Examples of Solving Buckling Studies Buckling Analysis of a Compressed Straight Beam Let s review the buckling analysis of a straight beam compressed with an axial P symmetrical load the Euler s problem A straight beam of the length 1 width and height of the crosssection b and h respectively is cantilevered at one end and a compressing load P acting on the other end Sought is the load factor V corresponding to the start of the beam buckling she h Assume the beam length equal to 0
116. nergy density of deformation uq therefore the criterion refers to the density of the potential energy of deformation We will derive the formula for the potential energy density due to distortion from the formula for the full potential energy density due to strain by using the specific Poisson s ratio of u 0 5 That yields 1 u E O 0 0 0 0 0 0 0 0 d 3E 1 2 3 17 2 2 3 1 3 The strength criterion appears as u4 u lt u where w Ho Consequently WV 2 2 2 equiv Or 2 2 2 p 2 2 lo 0 o 0f 6 0 62 r 72 lt o equiv The third and fourth strength theories produce satisfactory agreement of theoretical calculation results with laboratory test data for plastic materials and are widely used in strength analysis These theories are not applicable for brittle materials 98 Buckling Analysis BUCKLING ANALYSIS Equilibrium of a statically loaded structure is called stable if small disturbances cause small deformations In certain cases of loading structures situations are possible that are called buckling when small disturbances from the forces applied to the system cause large structural deformations which exceed those defined within the framework of the linear theory of elasticity Loads that cause buckling are called critical and the respective states critical states Under compressing forces which even insignificantly exceed the critical value additional bending stresses re
117. ng of the calculated model Coloring is done according to the properties of calculation results and settings of the color scale A color filling some area in the model corresponds to a certain numerical value Color scale setup is done in a separate dialog see below Only on surface Enables the mode of showing the mesh on the surface only When the flag is off the entire volume mesh 1s displayed Deformed state This flag controls the way of rendering the resulting finite element model it can be shown either in the deformed state or as the original Scale Sets the scale of deformations for the calculated model It can be defined in terms of a relative or absolute value Initially the scale is picked up by the system automatically but the user can change it as desired Animation This flag turns on the animation mode of the postprocessor window in which the deformation values smoothly vary from zero to the calculated value To control animation and the deformed state rendering one can also use a floating bar that can be accessed from the context menu in the postprocessor window the command Strain state window or Time process window depending on the type of the result 70 Processing Results Postprocessor te Example grb Study _0 Task Study _0 Displacement magnitude m Displacement scale 1229 66 5291 FOO3E 006 Render Projection Clip plane 5 62344667E 006 Rotate Camera Labels 3 7 4696445E 006
118. ngth against buckling 81 T FLEX Analysis User Manual STATIC ANALYSIS The main goal of the static strength analysis of structures is evaluation of a stress state of a structure subjected to constant in time static forces This evaluation of the stress state is usually performed with the purpose of probing the adopted design features against the strength criterion The strength criterion is generally formulated as follows The stress developing in a structure under applied external forces must be less than the safe stress o for the given structural material after applying the strain margin of safety factor Kafe o K lt o safe The static analysis module of the T FLEX Analysis Finite Element modeling system serves for calculating a static stress state of three dimensional structures in T FLEX CAD environment The static analysis module works directly with three dimensional T FLEX CAD models and and does not require additional constructions for solving a particular three dimensional model The main results of a static solution ommmemmamr File Edit Construct Draw Operation Title Block Analysis Parameters Tools Customize View Window Help are lpwaedla 4 04 FUAZS AlO L 6 OR GO 9 0 Wile E 30 280 2 E e structure s displacements field at the calculation points of the finite element mesh HE e relative strain field ara e stress components field aay ae ee dr
119. nonspecialist in the area of finite element analysis and does not require the user to have in depth knowledge in the area of mathematical modeling for effective use of the system Nevertheless correctness of results of a mathematical modeling and their appropriate assessment are determined to a significant degree by the user s proficient approach to formulating physical problems which are to be solved with the help of T FLEX Analysis The center point of the finite element method is in replacing the original spatial structure of a complex shape by a discretized mathematical model that appropriately represents the physical essence and properties of the original product The most important element in this model is the product s finite element discretization which implies building a set of elementary volumes of the specified shape the so called finite elements FE combined in a united system the so called finite element mesh T FLEX Analysis is oriented at solving physical problems in spatial formulation The product s mathematical approximation uses its equivalent replacement by a mesh of tetrahedral elements A tetrahedral finite element is convenient for automatic generation of the computational mesh since the use of tetrahedra permits a high accuracy approximation of a however complicated product shape NAAN Z AA WAAL A EDK wN w me ly Merz q ore AE EE TAS wean ma Z sf
120. nsfer and thermal conduction problems A typical goal of performing thermal analysis is finding temperature fields and heat thermal flux within a product s volume T FLEX Analysis supports two ways of formulating a thermal analysis problem e Steady state calculating temperature fields and heat flux distribution under the assumption of an infinitely long time passing after applying thermal loads A body s temperature does not change with time in the steady state so that an elementary body volume loses as much energy to the environment per the time unit as it gains from outside or from internal heat sources e Transient process temperature fields calculation occurs as a function of time The temperature field distribution pattern changes with time in the analyzed physical system so that the study results in obtaining temperature fields at each time instant of a certain time period set forth by the user T FLEX Parametric CAD E 9050 grb T FLEX Parametric CAD E chip radiator grb File Edit Construct Draw Operation Analysis Parameters Tools Customize View Window Help fence Sms B48 G2 49 9 02 Fae OcHoBHol yaf gt Ayo Sc acai we ie ed Te TD i sg a m File Edit Construct Draw Operation Analysis Parameters Tools Customize Yiew Window Help oaas amp fs a vige HA Somme ms FF LAME HDD amis O x E chip radiator grb B00 E chip radiator grb Study_0 DAR A Task Study_0 Temperature C 41 9
121. nstead of iterative method if the iterative algorithm does not converge to the stable solution or if the convergence speed is very small the number of iterations is several thousands This situation can be observed for thin problems the model is flat or stretched and also for a large number of finite elements which are considerably different from equilateral elements when the ratio of the lengths of the finite element edges are on the order of hundreds or thousands Calculation Method Direct Options Iterated Options Relative accuracy Maximum iteration Finite Element Method coe rob Iterated The systems of equations are solved by iterative methods This method is used by default for solving systems of equations built based on a quadratic finite element The following two options can be set for the iterative method relative tolerance and the maximum number of iterations Relative miscalculation the accuracy of the achieved iterative solution The smaller is the specified miscalculation error the greater number of steps iterations will be required Maximum number of iterations the critical number of iterations after reaching which the iterative solving of the system of equations terminates even if the required solution precision was not achieved The user can also manage interaction with external disk memory of the computer system when solving SLAE by a direct or iterative method
122. nt magnitude of uniformly distributed along the edge length over the face area load When the Force is uniformly distributed the load per unit length of the edge per unit area of the face is equal to the ratio of the specified load magnitude to the edge length face area It is worth noting that if the load magnitude is specified simultaneously for several elements it is allowed to select the elements of a single type only vertices edges or faces its total value will be distributed between them in the following way e The load magnitude equal to the ratio of the specified load to the total area of the faces will be acting on a unit area of each face e The magnitude equal to the ratio of the specified load to the total length of edges will be acting on a unit length of each edge e Each vertex will be subjected to the part of the force equal to n where n is the number of vertices Units For the load Force the following units can be used N lbf kgf Load direction As a direction of the Force the user can select the normal to the loaded face the element of a 3D model or a certain radius vector specified in the selected by the user local coordinate system if the local coordinate system is not specified the global coordinate system will be used by default To work with the local coordinate system use the following options For specifying the load direction with the help of a 3D model use the following automenu option
123. nts C Show Studies Window Yariables AY x E N Expression i Diagnostics Variables IE 3MM Mew Study Creating finite element analysis problem By default the Analysis Mesh command is started automatically when creating a new study Thus upon the successful study creation a dialog appears providing controls for finite element mesh generation upon the successful completion of the latter we obtain a meshed model made of tetrahedra approximating the solid model of the part 7 T FLEX Parametric CAD C Nprnepbi Body grb F File Edit Construct Draw Operation Title Block Analysis Parameters Tools Customize View Window Help l lpeaed a F 04 ZAUAAA AlO lL e OROO B Gl Defaut 30 gt H I Enska aae Mesh Parameters Elements Tetrahedron 10 nodes Delete Mesh Size Propagation 0 1 E H W Curvature 0 0 5 0 15 Minimum Curvature Relative 0 01 W Optimize Surface Mesh 3 k la be sO O ONTOS tll 11 T FLEX Analysis User Manual The Analysis Show Studies Window command opens the study window which displays the studies present in the current document and their elements in a tree view The just created study becomes active The newly created study elements and the issued Analysis commands will pertain to the active study 7 T FLEX Parametric CAD C Nprnepbi Body grb File Edit Construct Draw Operation Title Block Analysis Parameters Tools Cust
124. omize View Window Help PawaAcala Poje O 2 AA l e 6 ola age cl DeFault F z pi 0 gt 0 mm El or ar sO P SL al Studies Alx TX Studies Body grb El oe Study Elf Body_o lS Mesh_O ges REO SOM PS Hl at gt Enter command or select element E If there are many different studies in the document then only one of them can be active Switching an active study is done via the context menu accessed by B understudy name The Activate command is provided for inactive studies 12 Step 3 Assigning Material Introduction To perform any calculations with the solid model of a part you need to define the material from which it is made T FLEX Analysis provides two ways of defining a material for performing analysis By default calculations use the material properties by operation Material assignment for a three dimensional model is done in the operation s properties window To check or modify the material in this case called the operation s properties window from the context menu by 3 on the three dimensional body resulting from the operation or on the operation name in the studies window t T FLEX Parametric CAD C Nphmepbr Body grb F peaecuala cl Default Studies EES D ts Body grb Studies Body orb El a Study 0 ls Mest Delete body Measure visibility Boolean_14 I3 Save Detail Create Driving Dimensions Book
125. onditions In static analysis boundary conditions are represented by restraining methods and external loads applied to the system The boundary conditions creating stage is very important and requires good understanding by the engineer of the essence of the study being solved Therefore think over the physical aspects of the study thoroughly before applying boundary conditions Defining restraints is a necessary condition for running a correct static analysis The combined limitation on the body movement must satisfy the following condition To be suited for a static analysis a model should have restraints preventing free movement in the space as a solid body Failing to meet this condition will cause incorrect results of Finite Element analysis or abortion of computations 83 T FLEX Analysis User Manual 84 Two commands are provided in T FLEX Analysis for defining restraints Full Restraint and Partial Restraint The Full Restraint command sets a fully fixed immovable state for the selected model element The Partial Restraint command allows selectively limiting model element motion along the axes of the chosen coordinate system The Partial Restraint command also provides another useful functionality The user can specify known displacements for the structure such as a known in advance strain in the structure For this specify the value of fixed displacement of a model element along some of the coordinate axes in the P
126. operation implies lasting influence of loads ranging in intensity With the help of this module the user can evaluate safety margin by the so called critical load Significant nonelastic strains may occur suddenly within compressed parts of a structure which could likely cause its rupture or serious damage e Thermal analysis is the module providing the capability of evaluating a heated product behavior under the impact of sources of heat and radiation Thermal analysis can be used independently for calculating temperature and heat fields through the volume of a structure as well as in combination with static analysis for evaluating thermal deformations building up in the product About Mathematical Background of T FLEX Analysis Engineering design often requires investigation of the most important physical and mechanical properties of parts assemblies or the entire product For example in a design one must evaluate the strength of parts under specified loads or maximum deformations of a product s body For a long time the only means for evaluating physical and mechanical properties of products was assessment based on approximate analytical or semiempirical methods listed in industry guides The accuracy of such methods is generally not high with respect to real life design objects Consequently significant safety factors as with respect to the strength are incorporated in order to lower the risks of an unviable design Emergence of
127. ort template specifies the path to the html document with the report template Clicking the button allows selecting another report template Clicking the button Create brings up the dialog for saving the report file By default the report is saved in the current folder of the model file and uses the name in the format model file name study name html When generating a report a folder with the same name 1s created to store the files of graphic result images in the bmp format Keep in mind this fact when porting a report to another work seat or when passing to a third party 77 T FLEX Analysis User Manual Report Templates As we mentioned study reports are generated using templates A template is a common html document The template that is installed with the system has the name TFA _common html and is located by default in the program folder of the T FLEX CAD installation The contents of a template can be edited in a textual or html editor A user familiar with html programming can make changes to the standard template or create one s own template based on it and then use the new template for generating reports on studies The idea of generating a report by template is simple The reports generator looks through the template text and analyzes its contents The template contains special fields using reserved notations so called tags such tags are replaced by the respective values of properties of a study for which the re
128. pointer The user needs to simply point the mouse at the location of interest on the meshed model and the exact result value will be displayed at that spot Sampling also works in the mode of displaying the deformed model state To sample inner portions of the model you can use a T FLEX CAD tool called Clip plane Creating report results of a solved study can be saved as a separate electronic document The dialog for generating a report of the active study is accessible via the Analysis Report menu or from the Report context menu item of the study selected in the studies tree Coloring Properties Logarithmic f Linear Maximum f sutomatically 2 81829E 006 m 2 515256 006 mi en yalue T value Minimum sutomatically T Absolute value Standard g save Reverse toad Colour Spectrum Scheme J Gradient Threshold level Level z Legend E Display minimum on top W Display marks M Number of marks M Display Zero Mark Show maximum always Show minimum always Default Introduction 01029e 006 2 6e 006 2 4e 006 2 2 006 26 006 1 8e 006 1 6e 006 146 006 1 2e 006 Le 006 Ben e 007 4e 007 cent k 1 79946E 006 4 4 21 T FLEX Analysis User Manual PREPARING FINITE ELEMENT MODEL FOR ANALYSIS PREPROCESSOR The main purpo
129. port is being generated Table 1 lists the tags and their values used in the report template List of Tags for Generating Reports Table 1 omments to the study defined in the study properties dialog Fi 5 Soli 5 i ae ConditionName Name ID of the boundary condition ConditionParent he model element for which the boundary condition was created 78 Processing Results Postprocessor ConditionParameters he boundary condition value load temperature etc Resa ResultBitmap Link to the result image Example of Interpreting a Result In this paragraph we will provide an example of detailed result interpretation for a specific structural study and then take all necessary measures to fix the model s flaws The original model is a mounting part whose drawing is shown below The mounting is loaded with the force of 3500 kilograms evenly distributed over the horizontal plate The model material is steel There are two restraints a full restraint at the bottom hole and a partial restraint with the ban on longitudinal axial displacements for the vertical plate The main criterion for assessing the structural strength is the Factor of safety FS as we mentioned earlier The minimum FS value for this part should be no less than 1 5 After getting first results one can see the general picture of the factor distribution shown on the color diagram at the right 160 Task Study_0 Min 0 6027 eerie
130. ptions For specifying direction of load Acceleration with the help of an object of a 3D model use the following automenu option Select direction To cancel direction selection use the option ay Cancel direction selection For a change of load direction to an opposite one the user can activate the flag Reverse direction e For a quick specification of the gravity force in the properties window there is a button Gravity force which sets the value of acceleration equal to 9 81 m c and sets the direction of load along the Z axis of the global coordinate system equal to 1 In the 3D scene the load Acceleration is shown in the following way Specifying load Acceleration Preparing Finite Element Model for Analysis Preprocessor A typical sequence of steps to specify the load Acceleration 1 Initiate command Acceleration 3 2 Specify the load magnitude 3 Specify the direction of load 4 Complete the command Bearing Force Bearing Force simulates the load occurring under a direct impact of such parts as an axle a bearing or a shaft A cylindrical face is used as the location for applying the load The applied force is distributed according to the sinusoidal law see the diagram Selected cylindrical face Load application direction Load distribution by the sinusoidal law Distribution maximum To specify Bearing load use the command Keyboard
131. quations are solved at each time step defined by the user The Results tab allows defining the result types displayable in the studies tree after finishing calculations Thermal Analysis Study Properties Thermal z a i ka CANE General Parameters Solve Results BB otal Load M Save solving results in file Result List Use this command to set up items displayed in the studies tree Total Flow Thermal Gradient O Prescribed Temperature i Thermal Gradient O Temperature 0 Thermal Gradient 02 Thermal Flux Cn T Thermal Gradient tud Thermal Flux C fod J Thermal Gradient magnitude Thermal Flux OZ El Thermal Flux H 4 Thermal Flus O J Thermal Flux O v i A Thermal Flux OZ i E Thermal Flux magnitude Default Cancel Results tab left and dialog for setting results displayable by default in the studies tree right Thermal Flus magnitude Examples of Thermal Analysis Studies Thermal Analysis of a Cooling Radiator Steady State Required is an evaluation of a passive cooling radiator efficiency for the semiconductor electronic device with the maximum dissipating power of 15 Watt The permissible temperature of the microchip s body is 75 C in the operating range of ambient temperatures from 25 C to 55 C An aluminum alloy radiator is used for cooling the device and is mounted at the top of the microchip s body To improve heat dissipation the body of the microchip is also made of al
132. range will be assigned a color according to the color scale settings In this way of displaying the result one can instantly notice the places of the model that require fortification We also see from the scale that the minimum FS value is 0 6 which is not admissible We then proceed with fixing model flaws First of all let s strengthen the pillars by increasing the cross section area and the area of the vertical and horizontal plates connection Also when analyzing the general picture of factor of safety distribution one can discover zones of excessive strength This allows saving material Thus it is possible to reduce the thickness of the vertical plate and eliminate rigidity ribs on it The new mounting drawing is shown below 80 Processing Results Postprocessor Task Study_0 Factor of safety Min 1 4927 1 0000 1 4905 2 2312 3 3401 5 0000 Max 2562 6631 After updating the mesh and running calculations ask Study th ala that the fact f saf Relative Displacement magnitude e second time we can see that the factor of safety Buckling Mode 1 Load Factor 78 93 no longer reaches critical values in the problematic zones To state the final conclusion about the strength of the mounting we must run the buckling analysis of the part Such an analysis indicates that the critical safety factor for the mode and this type of loading is 79 which means a sufficient margin of structural stre
133. re saving the mesh In this way the boundary conditions are left unaffected Upon the next opening you would have to create the mesh again and run calculations 69 T FLEX Analysis User Manual Settings and Service Commands of Calculation Results Window Customizing Calculation Results Window The viewer s settings are accessed by double clicking vS in the results viewer window or from the context menu Yiew Properties E Viewing Results Additional IY Coloring Setup Mesh M Only external Faces I Loads Restraints IY Deformed state Relative scale 5 body size Absolute scale 1 1748e 006 Animation Negative deformations Frequency L min 10 M Variable coloring Model Solids Extrusion_O Loads Restraints W Model Contour W Contours of all bodies Render Projection Rotate Information Panel M Study Mame W Result Type W Coloring Scale Clip plane Camera Tr F F F F F Labels ne Hide 30 Annotations bl Strain State window Numeric Values E Units m i a Numeric Format settings SD view Parameters Default Cancel Apply Dialog for customizing parameters of calculation results window F Coloring Properties Opacity Parameters dialog of the calculation results window has three groups of settings The Viewing Results group provides the following controls Coloring This flag toggles the mode of colored renderi
134. ritical load which brings the system into a new equilibrium state For example a distributed force of 1000 H is applied over the model The Load Factor as calculated is equal to 109 18 That means that the first mode of an equilibrium state for the given model has the critical load equal to 109180 H Load Factor must be positive If calculations have resulted in a negative Load Factor that means no buckling can be produced by the loads applied to the structure 100 Relative displacements corresponding to a given critical load This type of result reflects on a buckling mode of the structure corresponding to a certain critical load The buckling modes displayed in the postprocessor window after completing calculations are relative displacements By analyzing those Buckling Analysis modes you can make a conclusion about the pattern of displacements in a buckling condition By knowing the expected buckling mode under a certain critical load one could for example introduce an additional restraint or a support in the part of the structure corresponding to the maximum of buckling in this mode which would effectively alter mechanical properties of the product As an additional reference result you can also output displacements of the structure under the applied static loads whose calculations preceded the evaluation of the critical load factors Relative Displacement magnitude a Relative Displacement magnitude ae Buckling Mode 1
135. rning on the Display this dialog box before solving flag This allows specifying study properties and adjusting calculation algorithms before the execution The Results tab shows the list of results displayable in the studies tree after finishing calculations 1 Main Normal Deformations 1 a ae C Main Normal Deformations 2 This list can be set up in the dialog accessible by clicking the EO Main Normal Deformations 3 Stress Options button The user can set checkmarks against any item EJ Normal Stress 0 if one is planning to investigate the corresponding result in the future C Normal Stress O Y The marked items will be output in the studies window The desired Souu n f f o b Shear Stress in plane X02 results could further be loaded into the calculation results view o o E Shear Stress in plane YOZ window o h 0 Shear Stress in plane 0 E Main normal stress 1 The user can customize the results list either before or after o e C Main normal stress 2 i calculations are completed The total calculation run time does not F Defaut ae depend on the number of output results The system will calculate all results anyway but will display in the studies window only those Dialog for setting up the list of Results selected by the user displayable in the studies tree Defining Material Material is an element of the T FLEX CAD It contains the list of characteristics of a real material which the user
136. rtain set of settings new properties and solving methods depending on the chosen type Other study settings can be edited after its creation in the properties dialog A study s properties dialog box may automatically appear before running calculations or when calling the respective command from the context menu called by right clicking B the study in the studies window as well as from the studies list management window General Properties of Studies A number of similar properties exists in all types of studies defined on the General and Results tabs in the parameters dialog Study Properties Linear Static Study Properties Linear Static Ea General Solve Nonlinear Thermoelasticity Results General Solve Nonlinear Thermoelasticity F esults Gener 9 ttt Marie Studyo Type Linear Static Comment lial Result List Use this command to set up items displayed in the studies tree Operations Factor of safety by equivalent stress Materials Thickness fim A M Display this dialog box before solving cet ee Cancel Help Preparing Finite Element Model for Analysis Preprocessor On the tab General the user can specify the study s name modify its type Static Analysis Frequency Analysis Stability Analysis Thermal Analysis and enter the comments Comments are used for recording necessary explanations and are output at the time of generating a report We recommend tu
137. rts of the structure corresponding to volumetric bodies with comparable sizes along three space dimensions are approximated with tetrahedral elements Thin walled parts of the structure are approximated with laminar finite elements 24 Preparing Finite Element Model for Analysis Preprocessor Laminar finite elements _7 2s lt lt A et r TAN O S257 SO a a I oe Se a ne ee a a a a a a E a Ie a I awe OOS ee Sie aa d KORKIN Knas ANNAS a a DA 7 TA foal A Wa Fy a MEF S JOSS Nee rea eA VSL 5 a Cs ha Fi M D ea Examples of structures and their hybrid finite element models Purpose and Role of Meshes The main purpose of a finite element mesh is to adequately approximate geometry of the body being modeled accounting for all features of the part geometry significant to the solution The T FLEX Analysis Preprocessor uses an effective automatic generator of finite element meshes which lets the user control various modes of mesh generation in order to obtain meshes of the desired quality on different models In T FLEX Analysis volumetric tetrahedral and triangular surface finite elements are used in finite element meshes which in theory allow approximation with any required accuracy Nevertheless there are several preliminary recommendations regarding adequacy of calculation models using finite elements
138. s e mesh e material e restraints e loads Step 5 Running Calculations After creating a finite element mesh and applying boundary conditions you can launch the command Analysis Solve and start the process of generating systems of linear algebraic equations SLAE and their solving 18 Introduction The Solve command can also be accessed from the i udy Properties Linear Static context menu of the respective study in the studies tree displayed in the studies window The modes of generating the SLAE and methods of their solution are selected automatically by the processor of the T FLEX Analysis The user can manually modify calculation options in the study s properties dialog which opens automatically before the beginning of calculations While solving SLAE a dialogue is provided that displays solution steps The process of solving SLAE might take significant time for studies using meshes of a large number of tetrahedra Once solving completes the respective diagnostics message is output General Salve Nonlinear Thermoelasticity Results Calculation Method Direct Options Iterated Options Relative accuracy Maximum iteration Finite Element Method Element Type Quadratic i Recommended For numerical stress limit calculation cot mob T FLEX Parametric CAD C Nphnepbi Body grb F File Edit Construct Draw Operatio
139. s then the finite element model correctly accounts for the different material properties of different faces of contacting bodies If the contact area is not subjected to any restraints then use the No Contact type In this case the contacting surfaces can freely move with respect to each other Therefore when using this contact one should be on guard against mutual penetration of contacting faces when a load is applied The Touch contact differs from No Contact in that it bans mutual penetration of the contacting faces This contact type allows modeling such physical phenomena as sliding of one body along another one occurrence of gaps at the part connection locations due to deformation etc We would like to also note that using the Touch contact implies existence of a physical contact between body faces in the initial state of the structure being analyzed Hard Wall is used to model a contact of a body with a rigid surface whose deformation can be neglected for the modeling purposes In this case all that is necessary is to define the faces of the first body that contact the Hard Wall It is possible to set default contacts Keyboard yy Contact Parameters This command defines the contact type to use by default This serves to define global contact parameters for all bodies in contact For example if a combined structure is being calculated that consists of several rigidly connected parts the
140. s to tens or hundreds thousand algebraic equations By building the system of equations for the entire structure and solving it we get the values of the sought physical measure for example displacements in the nodes of a finite element mesh as well as additional physical measures for example stresses Those values will be approximate with respect to the theoretically possible exact solution of the respective differential equation of mathematical physics however with the miscalculation error being possibly very small fractions of a percent on test problems having exact analytical solution The error of the solution obtained as the result of a finite element approximation 1s usually decreasing smoothly with the increased degree of elaboration on the modeled system discretization In other words the greater is the number of FE involved in a discretization or the smaller are the relative dimensions of a FE the more accurate is the resulting solution Naturally a more dense subdivision of FE demands more computational power Results of finite element modeling displacements and stresses The described algorithm of finite element modeling is applicable for solving various problems which a modern engineer may encounter heat transfer electrodynamics etc Due to advantages accounted for above FEM became the leading method of computer modeling of physical problems and in fact associates with a whole branch of the modern IT i
141. se of the T FLEX Analysis Preprocessor is preparing initial data on the physical problem to be analyzed in the form of a finite element model which would adequately reflect on the geometrical and physical properties of the part being modeled This finite element model is then processed by the T FLEX Analysis Processor which results in a solution to the posed problem Preparing a finite element model does not require specific knowledge on the finite element analysis from a user It 1s conducted on the basis of a geometrical model interactively using the Preprocessor commands whose function is described in this chapter Use of the Preprocessor results in a finite element model of the part containing e finite element mesh e materials data e boundary conditions corresponding to the physical problem being modeled The order of building a finite element model in T FLEX Analysis is arbitrary in most cases meaning that the user can first build the finite element mesh and then apply boundary conditions or on the contrary first specify loads and restraints and only afterwards generate a mesh of finite elements Nevertheless an unavoidable condition for a proper finite element model is the presence of all its required components a mesh of finite elements tetrahedra material properties and external impacts on the system The mesh and boundary conditions are visually displayed in the T FLEX CAD model window directly as the mesh or by using spe
142. select desired ones Create Mesh Selection of objects can be carried out with the help of the option Click to select Element Body Face The user can cancel selection of all objects with the help of the option fs lt R gt Cancel selection When analyzing thin walled structures the user can determine which fragments of the model have to be discretized with laminar triangular finite elements and which fragments with tetrahedral finite elements That is why for Elements of Study which will take part in calculation it is required to select the faces and or bodies For each selected face specify the Thickness 29 T FLEX Analysis User Manual Properties E Type Static Analysis Study Elements Face 1 Extrusion_1 surface Thickness 1 W Create Mesh The system allows using several selected elements of the study in analysis including elements of different types bodies and faces in this case the result is the so called hybrid model consisting of shells and solid bodies Given that all elements of the study are treated as a single whole similar to a glue joint and one mesh is calculated for them That is why every element of the study necessarily has to be contiguous with at least one of the remaining elements taking part in analysis and these elements cannot penetrate into each other For each element the material properties can be specified A created study gets a ce
143. shold Accordingly the magnitude of the maximum principal stresses 1s limited so as not to exceed the maximum principal stress lo The strength criterion appears as Pw lt lo if O gt and o equiv I equiv where o lo if 0 lt S o3 lo Second strength theory The second strength theory uses the maximum strain as the ultimate strength criterion According to this theory the unsafe state of a material occurs when linear strain reaches a certain safety threshold For a plastic pJ max El lt e D material the strength criterion appears as If for example l maxle s lo vlo 03 H then O equiv O _v o o lt lo For brittle materials the strength criterion appears as The first theory yields good agreement with experimental data only for brittle materials The second one 1s practically abandoned nowadays 97 T FLEX Analysis User Manual Third strength theory In the third strength theory the ultimate strength refers to the maximum sheer stress According to this theory the unsafe state occurs when the maximum sheer stress reaches a safety threshold lo where z a Consequently O 17 O 3 The strength criterion appears as Tmax aa Oyi F 93 lt o Fourth energy strength theory The fourth strength theory is based on the energy approach based on the hypothesis that the cause of an unsafe state is the magnitude of the potential e
144. sotropic materials the Poisson s ratio lies in the range 0 lt u lt 0 5 For various steel grades E 195 206 GPa u 0 23 0 31 for aluminum alloys E 69 71 GPa u 0 30 0 33 Elastic properties of some materials are given in the table the denominator indicates the respective compression property Property Steel ST 3 200 240 240 450 Pn Static Analysis Steel 30HGSA 200 950 950 1200 fas Cast iron S Ch 150 640 15 32 copperwire 110 2sors0 320 15 Delta wood 250 160 plywood A material s plasticity properties are the relative elongation and relative contraction at rupture F EF 0 0 where lo Fo the length of the working part of the specimen and the area of the cross section before strain lk the length of the working part of the specimen after the rupture Fx the final area of the cross section at the specimen s neck after the rupture The plastic and brittle material states are distinguished by the amount of relative elongation at rupture Materials developing sufficiently high values 0 0 gt 10 at the point of rupture are referred to as plastic materials those referred as brittle are the materials with relative elongation of 0 lt 3 For plastic materials upon compressing to nearly the yield condition the o f graph pattern is the same as in the case of tension Under a compression strain the specimen shortens meanwhile its cross section dimensions grow For certa
145. sses with the allowable stress for the model material one can assess the degree of the structural strength 3 Safety factor estimate Open the Factor of safety by equivalent stress result This result allows estimating the quantitative ratio of the safe stress to the calculated equivalent stresses specified in the material properties By default the result is shown on the logarithmic scale in order to reduce the range of color gradients If the ratio of the safe and calculated stresses approaches one or becomes less than that then the strength criterion no longer holds and therefore the design must be altered Settings of Linear and Nonlinear Statics Processor The user defined study properties are saved together with the document and are inherited upon copying a study The main purpose of the study properties is defining options required for the processor the result listings to be displayed after completing calculations in the studies tree as well as keeping the descriptive attributes of the study as the name or a comment The static analysis solution parameters dialog has five tabs The General tab serves for defining descriptive Study Properties Linear Static properties of the current study General Solve Nonlinear Thermoelasticity Results In the Name field the user can edit the study name EES assigned the system default at creation This name will O E be further on displayed in the studies tree in the results
146. study The deflection at the plate center is calculated by the formula 1 p 566 R w 2_ 13166 mm D E h N where q is the pressure amount R the plate radius D Dv flexural rigidity d v Thus the solution error in displacements is 0 6 2 R The stress on the plate contour is calculated by the formula o 0 75q 3 10 Pa The stress magnitude obtained in T Flex Analysis o 3 19 10 Ny os This solution error in stresses is 6 Analysis of a Spherical Pressure Vessel Given is a spherical vessel with the inner radius r and outer radius R The vessel is subjected to the internal pressure po and external pressure p Sought are the displacements of the inner vessel wall Due to the symmetry of this study we will consider the 1 8 of the sphere Assume the following source data Inner radius r 0 4 m Outer radius R 0 415 m Inner pressure po 200 MPa Outer pressure p 120 MPa Assume the material properties as E 2 1 10 Pa v 0 28 As in the previous study we need to apply the boundary conditions to account for the discarded portion of the sphere In this case we need to restrain normal displacements of all flat face points The pressure in the amount of 200 MPa and 120 MPa is applied at the inner and outer faces respectively 118 Verification Examples BOA ARK LS ATETA 4 Finite element model of 1 8 of a sphere with loads and restraints By completing the calculations we obtai
147. suring a reliable and trustworthy solution to the physical problem being modeled Types and Role of Boundary Conditions Boundary conditions differ depending on the type of the physical problem being modeled as follows In the case of the Static Analysis problem type the following represent boundary conditions e Full Restraint restraint e Partial Restraint restraint e Contact restraint e Force load e Pressure load e Centrifugal Force load e Acceleration load e Bearing Force load e Torque load e Temperature thermal load In the case of the Frequency Analysis problem type the following represent boundary conditions e Full Restraint restraint e Partial Restraint restraint In the case of the Buckling Analysis problem type the following represent boundary conditions e Full Restraint restraint e Partial Restraint restraint e Force load e Pressure load e Centrifugal Force load e Acceleration load e Bearing Force load e Torque load In the case of the Thermal Analysis problem type the following represent boundary conditions e Temperature thermal load e Initial temperature thermal load e Heat Flux thermal load 2 7 T FLEX Analysis User Manual e Convection thermal load e Heat Power thermal load e Radiation thermal load The essence of a physical problem is determined by the type of boundary
148. te element model Substantial class of structures used in people s life has a special geometric shape when one of the dimensions thickness is considerably smaller than two other dimensions width and length Such structures are usually called thin walled For example in mechanical engineering these structures can serve as the shells of various machines spiral of turbines in instrumental engineering flexible elastic elements accordion boots membranes including crimp plate springs in civil engineering coatings floors ramps sheds and aprons in shipbuilding hulls of ships in aircraft industry fuselage and wings of aircrafts in industry various tanks cisterns reservoirs etc 23 T FLEX Analysis User Manual BNE x 9 KS My Wy D gt I V A A WV DG A CN y Kh 7 N AD mar A T y AADO A V K T N 9 y PR DAA DORNO SAVVA EKV VV SYAY gt Examples of thin walled structures and their laminar finite element models For finite element analysis of thin walled structures instead of tetrahedral elements it is possible to use laminar shell finite elements that allow the user to obtain a satisfactory solution with smaller computational effort than when using three dimensional finite elements Hybrid finite element model includes finite elements of both types simultaneously pa
149. terations reaches the value larger than the specified one the calculations are terminated Appendix References Properties of Structural Materials A proper assignment of material properties used in the structure is an important prerequisite for correctness of finite element analysis The main properties of structural materials used for strength analysis in T FLEX Analysis are A material s Elastic Modulus E N m2 is the ratio of stress with respect to relative strain o Fe developing in a prism shape specimen subjected to an axial force in a tensile test In this case a uniform stress state exists in the mid part of the specimen in the longitudinal direction The value of the Elastic Modulus E on the strain graph o f is numerically equal to the tangent of the tilt angle of the linear segment E tgp on the stress graph when testing a specimen The physical sense of the E modulus is described as the stress required for doubling the specimen length However the value of elastic elongation seldom reaches even 1 for most of solid bodies The stress graph of the tested specimen has several special points corresponding to changes in physical properties of the material and is used for evaluating the degree of material reliability under load Elasticity limit O the stress that is the upper bound in effect of purely elastic strain 93 T FLEX Analysis User Manual 94 e AL The stress dilation diagram for plastic materia
150. th constructed by two 3D nodes or one of the axes of the local coordinate system Direction of an axis of rotation defines the direction of load according to a right hand screw rule For selecting a rotation axis use the automenu option lt A gt Select axis of rotation To cancel selection of axis of rotation use the option xt lt C gt Cancel axis selection In the load s properties window it is necessary to specify the magnitude of angular velocity and angular acceleration E Preparing Finite Element Model for Analysis Preprocessor For angular velocity the following units can be used radian per second rad sec degrees per second Common Load Parameters deg sec the number of revolutions per second anguiar Velocty fi Hz the number of revolutions per minute rpm tes rads For angular acceleration the following units can be 2 2 Angular Acceleration o used radian per second rad sec degrees per Axis Units Jradjs 2 nf second deg sec the number of revolutions per Edge _5 30 Path_0 2 second Hz sec the number of revolutions per 2 2 Set as default Las Cancel minute rpm Eea In the 3D scene the load Rotation is shown in the following way Specifying rotation A typical sequence of steps for specifying the load Rotation 1 Initiate command Rotation Specify axis of rotation 3 Specify the magnitude and units for angular velocity and
151. the rigidity can be increased by reducing the length and increasing the thickness of the object To reduce a part s natural frequency you should on the contrary increase the weight or reduce the object s rigidity 103 T FLEX Analysis User Manual Mode Shape 1 Frequency 104 6 Hz Mode Shape 2 Frequency 151 7 Hz Thus by calculating resonant frequencies at the design stage using the frequency analysis module and optimizing the part s mass rigidity properties the user can raise reliability of the structure being developed from the viewpoint of its vibro stability and vibrational strength Details of Frequency Analysis Steps 104 Frequency analysis is performed in several stages The sequence of the user s steps for putting together a study and running a structure s frequency calculation is in many parts similar to the algorithm described for the Static Analysis Therefore we will point out in this chapter only certain details specific to stability calculations l Creating Study When creating a study specify the study type Frequency analysis in the command s properties window Applying boundary conditions In a frequency analysis study the boundary conditions are solely defined by restraints Defining restraints is a necessary prerequisite for performing a correct frequency calculation The combined restraints on a body s motion must satisfy the following condition To be subjected to freq
152. the standard palette spectrum of five colors between the maximum and the minimum values obtained in the current calculation Range group of parameters sets parameters of distributing numerical values over the color scale Linear Logarithmic The logarithmic scale is used by default for displaying the Factor of safety result This is done in order to get a more detailed color picture in the most important subrange where the factor s values are near 1 The user can also switch the display mode to the linear scale for this result For other results the linear scale is always used Processing Results Postprocessor Coloring Properties Range Scale Linear Logarithmic Maximum 2 68 0085 automatically 2 90446 008 Ninn 2 r 2 4e 008 value 2 9044e 008 H um Minimum gt 2e 008 d automatically 792083 Mimie 2e 008 value 792083 A hyn j P 4bsolute value 1 5e 004 2 9044e 005 g 4 Colour Spectrum 1 eee Scheme Standard Save 4 1 4e 006 M Gradient Reverse Load j Threshold level T inez 1 26 008 Level 2 g Mime 1e 008 be O007 E Display minimum on top 4 M Display marks 6e 007 IY Number of marks 4e 007 M Display Zero Mark Show maximum always 2e 00 Show minimum always 792063 4d Default Cancel Apply Scale options setup dialog Maximum This interface item serves to set the correspondence between the ma
153. the structure The buckling analysis allows making a conclusion about directions and locations of maximum displacements corresponding to a critical load This information can be used for optimizing the product s design with the purpose of increasing its resistance to buckling Buckling Analysis Processor Settings Upon initializing the Analysis Solve command the dialog of defining study properties appears by default with several tabs to switch between The user can change the default study properties To access a study s properties one can also double click oE a study s name in the studies tree or in the context menu right click on the name of the selected study in the studies tree The user defined study properties are 101 T FLEX Analysis User Manual 102 saved together with the document and are inherited upon copying a study The main purpose of this study properties is defining the modes of the Processor s operation as well as the lists of results and the number of buckling modes displayable in the studies three after calculations On the General tab you can define or modify the descriptive properties of the current study the name the study type the comment On the Solve tab you can define processor properties for solving the equations Number of buckling modes The user can specify the number of critical loads and respective buckling modes EmA me to be identified For practical purposes the most important is the
154. tudies that have an analytical solution in order to assess the accuracy of the finite element analysis system output All examples brought up here it can be found in the Verification examples library of files Examples of Solving Studies in Statics Bending of a Cantilevered Beam under a Concentrated Load Consider a cantilevered beam of length L loaded with the P V force P at the right hand end The beam cross section is a rectangle of width b and height h lt o N L Sought is the maximum beam deflection Assume P 2000 N L 0 5 m b 0 05 m h 0 02 m After building the model we set up a study of the Static Analysis type and apply a finite element mesh to the model The beam material is left by default the Young s modulus E 2 1 10 Pa Poisson s ratio v 0 28 The left hand end of the beam is fixed and the right hand end subjected to the load amount P directed vertically downward Finite element model of the beam with loads and restraints Using the Analysis Solve command we will calculate the static solution of the beam Displacements of beam points The maximum displacement came out equal to 11 83 mm The analytical solution appears as 1 p 215 P P 3E J w 11 9 mm 116 Verification Examples 3 where P is the force the beam length the material Young s modulus J Eg the section s moment of inertia The solution accuracy is 0 5 Static Analysis of a Round
155. tudy use the command Analysis Report The report settings dialog can also be accessed from the context menu by right clicking on the name of the selected study via the command Report Processing Results Postprocessor A report contains basic information about the model materials and the computational finite element mesh as well as colored result diagrams which are displayed in the itle Study 0 studies tree or opened in the calculation results view Author far windows at the moment Connpany company SS Let s review the main controls of the report generation dialog Displacement magnitude General group contains information on the name of the Displacement OY d fi hi h h b d e Equivalent Strain study for which the report is being generated Title E aaivslenk aeS information about the report creator Author by default Normal Stress O Parameters the information is accessed from the document properties ee Normal Stress Oz and company information which is also accessed from the document properties by default e e R ET lat Diagram list control lets the user check mark the result PA 1 1 gt CiP Files T FLE 1T FLE P tric CAD 114F types whose graphical images will be added to the Program FiestT FLE aes Progr enerated report j W Display report Cancel IM Use image from opened results A button Parameters is provided next to the list of diagrams which
156. ture corresponding to the maximum vibration in this mode which would effectively manage the part s natural properties By default the vibration modes are displayed in the Postprocessor window without color coding the latter can be enabled in the visualization properties Mode Shape 1 Frequency 376 0 Hz Mode Shape 2 Frequency 612 4 Hz Mode Shape 3 Frequency 1087 2 Hz Mode Shape 4 Frequency 1129 8 Hz Consider also the convenience of animation for analyzing the pattern of the structure s motion at a certain frequency Remember to enable the Animation option in the properties of the calculation results window accessible by OO in the Postprocessor window in order to have an animation and specify the desired animation parameters Frequency Analysis Processor Settings On the General tab you can define or edit the descriptive attributes of the current study as the name or a comment The Calculation tab serves for defining ERSGRSRe Gti processor properties for solving equations General Calculation pesuts In the group Number of frequencies it is required to Number oF Frequences Number of F ies umber of Frequencies 4 T Non Stationary System e specify parameter Number of frequencies that is the user can define the number of lower natural frequencies of the structure to be evaluated T Don t calculate self Forms Solving Equations Solving System Customize
157. ue in the Value field 550 Newtons The specified force will be distributed evenly over the selected face Originally the force direction is assumed to be normal to the selected flat face If desired one can specify the direction vector of the force 7 T FLEX Parametric CAD C Nprnepbi Body grb Eile Edit Construct Draw Operation Title Block Analysis Parameters Tools Customize View Window Help aa acHla dele O lAl A aAa l l e l ge Gil Defaut g0 amp n Face_1 Boolean_i4 Delete aa a Distribution Uniform oF LA UE xT oa Bile AR lt I Normal Element kalal bk S O O pH EA t tll 17 T FLEX Analysis User Manual Upon completion of the loads creation command the introduced loads are shown by special marks on the three dimensional model of the part applied to the appropriate model elements 7 T FLEX Parametric CAD C Nprnepbi Body grb File Edit Construct Draw Operation Title Block Analysis Parameters Tools Customize View Window Help l lpeBedla F C AUANS HAlO Lp6 B e aGe B Gl Defaut JE o 2 OBOE FF e a aaea Studies Aix Studies Body grb El oes Study Elf Body_o H Mesh O H E Restraints 1 H E Loads 1 kai PPAPHHE Sth ie TA iA a g al 4 Upon a successful completion of the loads creation command there are all four elements in the studies tree required for running the calculation
158. uence for specifying the load Radiation Initialize the command Radiation el Specify radiation type Specify emissivity Specify temperature of environment and units Specify radiation viewfactor of a face oe a a a Complete the command Loads Compendium Table Load type Application Related objects Input parameters location Concentrated Vertex Objects selected for defining Unit system force amount force direction local coordinate system Uniformly Face edge Objects selected for defining Unit system force amount distributed Force direction local coordinate system normal to selected face Non uniformly Face Objects selected for defining Unit system force amount distributed force direction local coordinate distribution law system normal to selected face Bending Vertex face edge Local coordinate system Unit system magnitude of bending moments moments Uniform Face edge Objects selected for defining Unit system pressure amount pressure direction local coordinate system normal to selected face Non uniform Objects selected for defining Unit system pressure distribution pressure direction local coordinate law system normal to selected face Hydrostatic Face Local coordinate system Fluid density unit system pressure Centrifugal Body Objects selected for defining Angular velocity and angular Force axis local coordinate system acceleration values unit system Acceleration Body O
159. uency analysis a model must be restrained so as to exclude its free motion in the space as a solid body Failing to meet this condition will cause incorrect results of Finite Element modeling or abortion of computations 3 Solving Before running calculations the user should specify the number of natural frequencies and if necessary elaborate on the solution algorithm Analysis of frequency calculation results The results of a frequency analysis are Natural vibration frequency Hz corresponds to the expected resonant frequency of the structure In theory the number of natural frequencies is unlimited for any body The results reflect only the frequencies for selected modes of natural vibration Natural vibration mode with respect to a given frequency Let us illustrate the physical meaning of the vibration mode term A vibration mode shows what will be the relative deformations displacements in a structure in the case of resonance at the respective natural frequency Please take a special notice on that the vibration modes displayed in the Postprocessor window after completing calculations are relative amplitudes of vibration By analysing those modes one can make conclusions about the pattern of resonant displacements but not about their factual amplitude By knowing the expected vibration mode Frequency Analysis at a certain natural frequency you can introduce an additional restraint or support at the part of the struc
160. ule that prepares a finite element model specialized solver the user can choose one or more out of the four solvers depending on the posed tasks static analysis frequency analysis buckling analysis heat transfer postprocessor the module for visualizing and evaluating results We would like to point out also that T FLEX CAD is required for using T FLEX Analysis the former serving as an environment for the finite element modeling system Steps of Structural Analysis Any type of analysis is performed in several stages Listed are the steps required for conducting an analysis Following are the steps required for running calculations 1 2 3 4 5 6 7 build three dimensional model of the part create Study A study is created for one or more connnected solid bodies glued connection define more the material generate finite element mesh apply boundary conditions reflecting the essence of the physical phenomenon being analyzed run calculations analyze results The listed steps are valid for all types of analysis realized in T FLEX Analysis system The difference in the respective modeling steps for different types of analysis is in the types of applied boundary conditions only which depend on the study calculation type For example in static analysis and in buckling the role of the boundary conditions is played by the forces and restraints on the product in frequency anal
161. uminum Step 1 Creating Study meshing and assigning material Create a study of the Termal Analysis type using the command Analysis New Study based on two bodies the microchip and the radiator Generate a finite element mesh You also need to define parameters of the part s material By default calculations use material properties From Operation that is the material properties are automatically obtained from the product part s solid model This is especially convenient when a study includes bodies from different materials representing parts of assembly models In our case the Aluminum material was defined at creation of the 3D model of the radiator and the microchip with its physical and chemical properties contained in the T FLEX CAD 3D database Three dimensional model of the microchip with a passive Resulting finite element mesh cooling radiator 111 T FLEX Analysis User Manual 112 Step 2 Applying boundary conditions Let us specify thermal loads for the model We will apply the Heat power load of 15 Watt to the volume of the microchip and define the Convection boundary condition on the external heat sinking radiator surfaces with the convection parameter of 25 Watt m C and ambient temperature of 25 C We can disregard in this study the heat exchange factor of mutual and ambient radiation since their radiation contribution is vanishingly small at the expected temperatures tens of degrees
162. unterpart The hybrid element is used for static strength analysis of the models containing both linear plate like and 3D volume elements so called hybrid models Static Analysis The tetrahedral linear element analysis provides INSUFFICIENT accuracy of quantitative results Maximum displacement and stress results are much smaller via the calculation by linear tetrahedral finite elements rather than those achieved by more accurate methods It is strongly recommended to use quadratic element calculations for quantitative evaluation the default mode The Thermoelasticity tab allows defining the methods for calculating thermal loads Consider Thermoeffects Includes the mode of calculating loads building up in a structure due to the linear expansion forces under the condition of heat applied to the body Temperature of zero deformations the initial body temperature at which there is no thermal strain and there is no stress caused by difference in temperatures The user can specify temperature values in one of the existing scales K Kelvins C Celsius F Farenheit Define the method of specifying thermal loads in the Study Properties Linear Static General Solve Nonlinear Thermoelasticity Results W Consider Thermoeffects Mon stress State Temperature of zero deformations 295 Temperature Fields f Uniform temperature 295 Ik Use preset temperature Temperature
163. ur choice into a special file for future quick loading a file with the extension col The setup is performed in the right hand side part of the dialog where the color image of the scale is displayed On the right of the scale there are several triangular tags marking places for fixed colors on the scale Using those tags you can set a new place for a color on the Delete scale To move a tag depress the on it and while holding down the button drag To create a new tag with a new color perform at the right of the scale A standard Windows dialog for defining color will appear To delete a tag drag it beyond the color scale To change the color assigned to the respective tag double click Oo To access this scale settings you can also use the context menu accessible by right clicking B on the color scale image Gradient This flag enabled by default serves to set smooth transition from one color to another in the color scale Invert Serves to invert the color scale The Legend group provides the following controls Reverse This flag reverses the values scale This mode is used by default when displaying the Factor of safety result in the static analysis This is convenient for displaying critical values that are close to 1 in Red Show Marks When this flag is enabled the marks with numerical values will be displayed on the color scale in the results window Number of Marks Sets the number of displayed marks D
164. ustomize View Window Help l lapeaSed a O F ZUATZA aAlO L 6 H ORGBO B a Default gt 0 A eaten tai Y Body grb fat Sls akO EAS T tl When defining boundary conditions the finite element mesh gets automatically hidden in order to let you apply boundary conditions to elements of the three dimensional solid model faces edges vertices Upon successful completion of the restraints creation command the corresponding elements are displayed in the studies tree of the studies window signifying presence of the respective boundary conditions Restraints on the face are also displayed by special three dimensional elements decorations in the model window of T FLEX CAD T FLEX Parametric CAD C pumeppi Body grb File Edit Construct Draw Operation Title Block Analysis Parameters Tools Customize Yiew Window Help l lppaSsdla O ZUAAS lO ls 6 Bl ORGO B 9 was E E AE Studies Body grb nsii Studies Body grb El gp Study 0 S Body 0 H A Mesh_0 a 6B Restraints 1 H A Fixed Restraint _0 a _ dal bh s O O M HN ASt Introduction Step 4 2 Applying Boundary Conditions Defining Loads A set of special commands are provided in T FLEX Analysis for defining loads accessible from the menu Analysis Load Using the Analysis Load Force command select a face of the Body to which the load is applied In the command s properties dialog specify the force val
165. value of the critical load under which the structure may buckle you can optimize the part in order to achieve the safe condition For example for a slender object you can increase resistance to buckling by reducing the length or increasing the thickness of your object or create additional ribs for rigidity 99 T FLEX Analysis User Manual Details of Buckling Analysis Steps Buckling Analysis is performed in several stages The order of steps for the user to put together a study and run calculations of the structural buckling analysis is mostly similar to the algorithm described for the Static Analysis Therefore in this chapter we will just mention what is special for the buckling analysis l 2 Creating Study When creating a study specify its type Buckling Analysis Applying boundary conditions Just like in the static analysis the buckling analysis uses restraints and loads as boundary conditions All types of restraints and all types of forces can be used in the buckling analysis The thermal impact is defined in the same way as in the static analysis Defining restraints and forces is a necessary condition for running a correct analysis The combined limitation on the model must satisfy the following condition To be suited for a buckling analysis a model should have restraints preventing free movement in the space as a solid body Failing to meet this condition will cause incorrect results of Finite Element analysis or a
166. we recommend building a mesh of straight edged finite elements with a sufficiently small discretization step and use the latter for calculations instead The diagram below shows examples of dividing a model into finite elements of each type The size of mesh elements is somewhat exaggerated for better visual effect as compared to what is required for calculations SIR oO O Bee AC NAKS Original model Mesh of straight edged elements Mesh of curvilinear elements MV Setting up mesh updating parameters is done by selecting a choice in the dropdown list Two choices are provided on request ask and automatically at model regeneration Mesh size The finite element edge size in the mesh being generated can be specified as relative or absolute In the first case the size of edge is defined as a fraction of the model outlining box s longest side For the absolute size a finite element edge is defined in the model units The specified size 1s adjusted by the system to eventually get all mesh elements with edges of approximately the same size nearing the value set in the parameters The model elements selected for mesh refinement allow setting only the absolute size Global size propagation factor Controls the speed of mesh variation from reduced size mesh cells to large cells of the general size If the factor equals 1 default then the mesh size nearly doubles with each following element up until its size reaches the l
167. ximum value and the topmost color on the scale By default the maximum value is set but the user can enter one s own value of interest in the respective field Minimum This allows defining the correspondence between the minimum value and the bottommost color on the scale Otherwise this interface item is analogous to the previous one Absolute value Enables the viewing mode of rendering absolute values in the nodes disregarding the sign This is an auxiliary mode It can be used for analyzing results in the case when you are interested in the magnitudes of values of displacement components or other measures Input of the maximum and minimum values can be used for a custom setup of results rendering For example to display the Factor of safety result you can limit the maximum value of the safety factor in order to achieve a more intuitive result picture in the postprocessor window Color spectrum group of parameters allows adjusting the number of colors in the color scale Scheme There are seven predefined settings and one custom Standard This option displays the scale of five main colors Gray scale This option enables a grayscale display Full spectrum When using this option the scale appears as a rainbow of seven main colors Besides that there are the following color schemes Maximum Minimum Threshold Range 73 T FLEX Analysis User Manual 74 Custom You can manually set up the color scale and then save yo
168. y thermal 4 amp ve o buckling analysis A Loads A special Studies tool window is provided for handling studies the same functions are provided in the 3D Model window The studies z ofp a eng artial Restrain window displays in a tree layout complete information about prepared RIL Partial Restraint 3 studies within a given document and about all elements included in each 5 neg dil 4 study The window provides a quick access to elements of each study a Dey bese eee Each type of study as well as every study element is marked with a E Equivalent Strain s Equivalent Stress sef Factor of safety by equivalent stress specific icon Some study elements loads restraints results are joined into groups Several studies can be created in one document for running different calculations The study currently being worked on is called active The active study s icon has a red check in the studies window To make another study active use the context menu command Activate Working in the studies window is done using the context menu that provides all Begi Mesh_2 D Loads 1 necessary commands The contents of a context menu depend on what study En Resta ll Partial Restraint_9 Ml Partial Restraint_10 A special command is provided for managing the list of studies Tg Pattial Restraint_11 element was right clicked Preparing Finite Element Model for Analysis Preprocessor The dialog window o
169. you can use for calling the dialog for defining diagram display parameters Here you can specify the picture size in pixels and the background color You can also enable creation of preview and set up its image In this way the main report document would include reduced size images of result diagrams with the full size images being Diagram parameters Image width height background color ep aoe viens accessible by clicking on the small image when viewing IT Make preview the report file for example in the Internet Explorer The flag Save 3D Model will also create in addition to the pictures three dimensional models of results in the format vrml with color rendering and boundary conditions In the report next to the picture there will be available the _Cancel link to the vrml model of the corresponding result Note that for viewing vrml model via the Internet Explorer it is necessary to use independent plugin displaying vrml model for example Cortona Vrml Client http www cortona3d com or another analog width height background color Save 3D Model Use image from opened results allows adding to the report the currently opened diagrams in their current orientation the way they appear in the calculation results window If there are no open result windows or the control is not active then the diagrams are added to the report in the default orientation axonometric front Rep
170. ysis restraints only and in thermal analysis temperature and heat impact T FLEX ANALYSIS FINITE ELEMENT MODELING SYSTEM STEPS OF FINITE ELEMENT ANALYSIS T FLEX Analysis User Manual Quick Start Step 1 Preparing Spatial Solid Model of a Part Let s review a general algorithm of using T FLEX Analysis system based on the example of static strength analysis Suppose we are required to perform analysis of the strain state of the Body structure whose one face is subjected to a distributed load and the supporting bottom surface is fully fixed For analysis you need to have a three dimensional solid model of the part The user can create the module in the T FLEX CAD three dimensional modeling environment This can be a working model containing projections and complete working drawings which could be part of an assembly or a subject to calculating numerical sequences for CAM processing By using the T FLEX CAD command File Import one can load into the system a model for analysis that was created in another spatial modeling system Original structure For calculation purposes it is helpful to create in advance a special optimized version of the model an optimized copy maintaining a parametric relationship with the original For example one can delete small features from the original model which are not significant in the calculation such as small unimportant holes In this case the ca
171. ysis Processor with support of 64 bit instructions Intel Core2Duo AMD 64 and others Hard drive space for storing 80 GB and higher calculation results 5GB and large Operating system Windows 64 bit Windows XP x64 Windows Vista x64 Software T FLEX CAD x64 T FLEX Analysis x64 T FLEX Analysis System Installation In order to use the T FLEX Analysis application you need to have installed the T FLEX CAD geometrical modeling system Therefore before installing T FLEX Analysis system first install T FLEX CAD T FLEX Analysis system is distributed with a protection from non licensed use To work with the system attach the hardware key to a parallel LPT or USB port of your computer depending on the type of the key used Usually a single key shipped with the Analysis program can serve for access to several different programs for example to T FLEX CAD and Analysis ATTENTION The hardware key should be connected and disconnected only on a shut down computer and the peripheral device in case it is connected to a parallel port The hardware key driver is automatically installed together with T FLEX CAD installation Introduction Structural Organization of T FLEX Analysis Application T FLEX Analysis is organized in a modular structure which enables the user with a flexible approach to setting up an engineer s work seat The standard system installation package includes the following modules preprocessor the mod

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