1. Getting Started Using UM: Simulating Hybrid Models
Contents
1. Figure 3 5 6 Select Spring in the list of the standard parametric GE Fig 3 6 Universal Mechanism 5 0 38 Getting Started UM FEM Description Go position Parametric Parametric PAP AT CH GE position Material Parameters Color Standard Plane Ellopsoid Ring Torus Cone End fe pl const E Side Prnin Figure 3 6 7 Set parameter values as in Fig 3 7 GE position Material Parameters Color standard Spring E guatio R 0 015 0 002 cosip l cosp y 0 015 0 002 cosip JJ zinipe z 0 02 sin p1 j 0 03183 p2 Parameter limit pl 30 0000 B fete z pe 0 0000 31 41 10 ol const D Side Prin C p2 const 7 Side Pmax Battom Fugure 3 7 Let us add now a GE for the damping force element 1 Add a new GO 2 Rename it as Damper 3 Add anew GE to the GO 4 Set its type as Cone and parameters as in Fig 3 8a Universal Mechanism 5 0 Description GO position Cone Cone he ake GE position Maternal Parameters Color Radius BE 0 005 L Radius A1 0 005 L Height h i L Number of pomt Bottom circle Generatii 39 Getting Started UM FEM Description GO position Cone Cone Cone he ake GE position Maternal Parameters Color Radius He o m L Radius A1 o o L Height h lo L Number of poms Bottom circle Generatii Angles fo 4 0 00 be Angles fo O A 0 00 be Cl2. Figure 2 10 Note The initial set of modes includes rigid body modes which should be excluded according to the used approach for simulation Rigid body modes theoretically correspond to zero frequencies but in fact because of using numerical methods and round off errors these frequencies are small and close to zero but not exact zero In fact the Transformations Frequency field indicates the threshold value and all frequencies that are less than this value are supposed to correspond to rigid body modes Now we need to save the transformed data set 12 Point to Transformed in the Data set group Fig 2 11 Data set C Original Figure 2 11 13 Click the Save as button In the dialog set Path to subsystem data and click the Save button see Fig 2 12 Please note that the latter directory will further serve as a subsystem name Universal Mechanism 5 0 16 Getting Started UM FEM Save flexible subsystem data Fath to subsystem data Drmodelsflexbeam Cancel Figure 2 12 Preparing the data for flexible subsystem is done Universal Mechanism 5 0 17 Getting Started UM FEM 2 3 Creating the model The hybrid model of the slider crank mechanism includes two rigid bodies one elastic body and four joints Bodies e crank m length e con rod 2 m length e slider The crank and the slider are rigid bodies con rod is elastic subsystem in terms of UM Joints e revolution joint between Bas
3. 8 Select the Object simulation inspector and point to the Solver tab Set the following parameters e Solver Park e Type of solving Range Space Method e Simulation time 2 0 e Step size for animation 0 001 e Error tolerance 1E 7 e Computing Jacobian matrices on always default e Block diagonal matrices off Simulation process parameters Solver options Type of solvin C Null Space Method e Range Space Method C Gear Simulation time 2 O00 Step size for animation and data storage 0 001 Error tolerance 1E Compliant cut joints Block diagonal Jacobian Figure 2 27 Universal Mechanism 5 0 28 Getting Started UM FEM 9 Select the FEM Subsystems Simulation tab and set up all options according to Fig 2 28 Solver Identifiers Initial conditions Object variables Solver Identifiers Initial conditions Object variables ve Information FEM subsystems Tools ove Information FEM subsystems Tools Subsystem Con rod FEM Subsystem Corn rod FEM General Simulation riage Solution General Simulation Image Solution Options Damping Options Damping Genera W Gravity P Switch off all flexible modes Calculation of initial condition Z Fix modal coordinates Skorin Store values of modal coordinates Destinatia f hemor t File File d models slider_crank_fem Con rad FEM ir a ampir Z Internal dissipation Type of
4. El vibrostand User Expression Identifier All forces Joint force springrL Coordinates Angular war Reaction F Linear var Linear F D amperFL TE io S nine RE Generalized linear force 3 ha Cr amperFR DmperMotorBE ia SpringEL Analyzed varabl k DamperBL f Force Torque C dRiY f API Omege s pringEB Componen D amperBA sno FI Spring otorBL O Y mi Drao ma spring ator A springMotorEH m Spring otorFL Acts on body Electricmator Body he D amperhotorEL se D amperMotorBA m LamperMotorFH he L amperMotorFL F Damper otaorEH z Generalized linear force element Damper ot yy ini E F SpringMoterBA 2 F DamperhotorEH z Resolved in SC of body cco Ca a Figure 3 25 2 Open a new graphical window the Tools Graphical window menu command 3 Drag the created variables into the graphical window by the mouse 4 Let us select some node of the FEM model where we will calculate Z components of position and acceleration If the animation window does not show nodes of FE mesh select the FEM subsystems Image Set Image to full Turn on the Image Draw nodes check box Set non zero value in Node image for example 3 see Fig 3 26 Universal Mechanism 5 0 56 Solver Identifiers Initial conditions Object variables RE Information FEM subsystems Tools Subsystem Platform Getting Started UM FEM Object simulation inspector General Simulation Image Soluti
5. Initial conditions Object variables katin gt vibrostand Electricmotor whole list Name Expression Value Comment cotitflateral 1 00000E 0006 Lateral stiffness of mount element of electricmot cStifflangitudinal 1 00000E 0006 Longitudinal stiffness of mount element of electr cdisslateral 1000 Lateral dissipation of mount element of electric cdisslongitudinal 1000 Longitudinal dissipation of mount element of ele HLA 1620 Frequency of rotor rotation t p m omega nu pr B0 169 646 Angular velocity of rotor rotation tatart 0 5 Time of the beginning of rur tspeeding upo 2 Time of rur tworking J Working time tbraking 4 Time of runnirng out Integration Figure 3 31 10 Start the simulation process by the Integration button on the bottom part of the inspector Fig 3 32 depicts some simulation results Plots Coordinates of points Varables ia rn z Flatfarrn Coordinates of point 0 048 0 007 0 06 of body Platform Platform relative to Basel SC Basel projection Z 0 64 0 6 Ss ih Ria Re a ah a a RED NAR a 0 56 0 0 2 0 4 0 6 0 5 1 Ex 1 Ey 1 FA Universal Mechanism 5 0 61 Getting Started UM FEM I Plots Accelerations of points Variables L a z Platfarm Acceleration of point 0 048 0 007 0 06 of body Platform Platform relative to Basel SC Basel projection Z z mi mi mm mm mm mm mm mm mm mij mm mm a a Plots Yalues of force
6. 2 Select Joints jRotor gt Body in the tree of elements It is a joint of the Generalized type 3 In the Inspector window in the right part select the RTx elementary transformation Fig 3 19 This time function is set as time table of 5 rows see table 2 and Fig 3 19 Universal Mechanism 5 0 47 Getting Started UM FEM Table 2 Time table for the rotor apa e 2 surespeding up onegatspexting up satro tstartHspeeding upHworking EEA NONE omega t tstart tspeeding up tstart tspeeding_up tworking omega tspeeding_up sqr tspeeding_up 2 tbraking omega tworking omega t tstart tspeeding_up tworking omega tbraking sqr t tstart tspeeding_up tworking 2 omega tspeeding_up sqr tspeeding_up 2 omega tworking omega tworking ome ga tbraking sqr tbraking 2 x yano aat eg Body Body OO Rotor Body Type i Generalized TE ROy AT tc Z tumed on uti eF tih S ET type Car rt rotational t function ki Comments Text attribut Transformation vecta axis 1 0 0 v apo sy ab ODO Type of descriptio Expression de Time table Function File Pe S s tstart 0 tshart tspeed omegatspeeding up sqrlt tstart tshart tspeed omega tspeeding upj zgrltspeedit tshart tspeed omega tspeeding_up sqrltspeedi 100 omega tspeeding up sqrltspeedi Figure 3 19 Universal Mechanism 5 0 48 Getting Started UM FEM 4 Close the constructor window of the Electric
7. Lab urmt Cancel Accept as default Figure 3 16 3 Rename the subsystem as Electricmotor 4 Set the subsystem location as in Fig 3 17 Universal Mechanism 5 0 45 Getting Started UM FEM x Mame E lectricmotor gt ht oo Tope E included m ext VSI Edit subsystem General Position Identifiers Translatio Rotation x 30 00000000 x O oo000000 x O oo000000 x Translation after rotatio Figure 3 17 Universal Mechanism 5 0 46 Getting Started UM FEM 3 2 6 1 Setting angular velocity of the rotor Let us set the law for angular velocity of the rotor as it shown in Fig 3 18 Here we can see three modes speeding up a working mode and a braking mode During speeding up and braking angular acceleration is constant and angular velocity changes linearly see Fig 3 18 The law from Fig 3 18 is parameterized with the help of six identifiers see table 1 tstart tspeeding up tworking tbraking Fig 3 18 Angular velocity of the rotor Table 1 Identifiers _ Identifier Meaning Nominal angular velocity of the rotor revolutions per minute r p m Nominal angular velocity of the rotor rad s Time before speeding up s Time of speeding up mode s Time of working mode s 6 tbraking Time of braking mode s 1 Click the Edit subsystem button to edit the Electricmotor subsystem see Fig 3 17 New object constructor for the Electricmotor appears
8. appears Set identifiers value as follows torque 100 cdiss_crank 10 Geometry Description Joint force Jont torque i Expression Description of fore Pascal l expression F Ffw w t E sample estiiF u xledisstvaannpizinjont Figure 2 20 4 Add the rest three joints as it is shown in the Fig 2 21 z x z Mame iCrank Conrod a BF JE g NameliConnod Slider P AF AS g Nameljbase0 Side Jatt AS z Bod Body Body Body Body Body ak zj Type A Rotational Type A Rotational Type Z Translational Geometry Description Joint force Geometry Description Joint force Geometry Description Joint force Crank axis Y 0 1 0 v Hexbeam axis D O v axis 21 0 0 flexbeam axis 0 1 0 v Slider axis o 0 1 0 Slider axis o OO v Figure 2 21 Universal Mechanism 5 0 24 Getting Started UM FEM 2 3 5 Preparing for simulation 1 Save the model as Slider_crank fem File Save as menu command see Fig 2 22 Fath including object name dAmodelsislider_crank_ter c Cancel Figure 2 22 2 Generate and compile equations of motion Click the Object Generate equations menu item The new dialog window appears Turn on the Compile equations flag Change the Output language if necessary and click the Generate button Fig 2 23 Deriving and compiling of equations Parameters Protocol Forrnalizm for equati
9. exclude rigid body modes check boxes and set frequency value Fig 2 3 Nevertheless now we will use the wizard of flexible subsystem data in order to familiarize you with it The intermediate input fum file contains static modes and eigenmodes To finish preparing data it is necessary to orthogonalize modes It may be done directly in the ansys_um program and if necessary with the help of wizard of flexible subsystem data 1 Run UM Input program uminput exe 2 Click the Tools Preparing flexible subsystems menu item The main window of the wizard of flexible subsystem data appears 3 Click the 4 and select a file for the Data file Fig 2 4 2 5 Data file Dynodels flexbeam inputtum el Figure 2 4 Wizard loads and shows the data Fig 2 6 The General tab shows summary information about elastic subsystem see Fig 2 6 The Position tab see Fig 2 7 is used for setting position and orientation of the elastic body These transformations influence on the representation of the elastic body in the animation window of the wizard Flexible body in the starting position coincides with X axis that is not really comfortable to watch Now we will shift the beam along Z axis with 0 3 m 4 Point to the Position tab 5 Set Shift z to 0 3 see Fig 2 7 Universal Mechanism 5 0 11 Getting Started UM FEM Read FEM model of object Scan directory DAModelsvlexbearn s amp D Modelsiflexbeam ba Data Imported from pro
10. of this lesson where working under ANSYS environment is considered But nevertheless you will be able to complete the lesson using files prepared in advance Copyright and trademarks This manual is prepared for informational use only may be revised from time to time No responsibility or liability for any errors that may appear in this document is Supposed Copyright 2008 Universal Mechanism Software Lab All rights reserved All trademarks are the property of their respective owners Universal Mechanism 5 0 3 Getting Started UM FEM 1 GETTING STARTED USING UM SIMULATING HYBRID MODELS 1 2 SLIDER CRANK MECHANISM cccccsecceseseeseceseseneecnseceeesenseoeseseneseneeoneesees 4 2 1 Preparing ANSYS eCnvirOnMen ccccccssssccssssccsssscccssscccvscsscsssscccsssscocscssccsssssocssesssseess 6 2 2 Preparing con rod as an elastic DEAM ccccsscccssscccsscccssscccsscccsssccssscccssscesssccssscesess 7 2 2 1 Working under ANSYS environment 7 Dade Wizard of clastic subsystems ao NA oe a Akne Aa ene 10 pa PON aa ei RE A A A ET OT A 17 2 3 1 DN EELE EE E E E E E E na E E EA 18 Don CCA ANS HONG OG IG Ne ii ae Ee O o ER Rn 20 2 3 3 Creatine elastic SUBS S ae a a ea ea Aa ea babe 21 2 3 4 a E E A E E E E E E E E NM 22 pe Rei Pre Pate TOP SUN O oa a a ea aaa a elana 24 2h SUMAN aa ae aaa aa a aa a E 25 3 ELECTRIC MOTOR ON ELASTIC PLATFORM 31 Ili Preparine elastic platform oe icesss
11. Stationary forc fe Linear i Bilinear Stiffness matrix inane d Dissipative matrix inane d Figure 3 13 Universal Mechanism 5 0 42 Getting Started UM FEM Element matrix Elements coordinate coordinate OF Cancel Figure 3 14 The elastic force element is described Now let us describe the front left damping element t 1 Copy the linear force element by the button 2 Rename the new element as DamperFL forward left set the element type Dissipative and set GO to Damper Fig 3 15 X Name Spt pe Comments Test attribut Body Body Based Platiom Platform o Type Fy Dissipative GU Damper v Position Parameters Body Body System of coordinates at pt A SCA R o 00000000 x jo 00000000 x jo 00000000 x jo gt gt gt SE Figure 3 15 4 Let us set dissipative matrix of the element Select Parameters tab Click the 4 button in the Dissipative matrix box set the diagonal elements of the matrix corresponding to the translational degrees of freedom dxx dyy dzz and click OK Set the following identifier values dxx 1E3 dyy 1E3 dzz 1E3 Ns m Damping element is described Universal Mechanism 5 0 43 Getting Started UM FEM Create the rest three pairs of force element quite similar to the previous ones dp ol a Use the button to copy the description Do it in the following manner 1 Select previously described element o
12. Universal Mechanism 5 0 1 Getting Started UM FEM 1 Getting Started Using UM Simulating Hybrid Models The UM FEM additional module gives the user a possibility to create models of mechanical systems that include both rigid and elastic bodies so called hybrid systems Elastic displacements assumed to be rather small and describable by finite element method and linear theory This manual helps you to study main features of creating and analyzing hybrid systems using Universal Mechanism software Detailed information about UM FEM you can find in the 11_ UM_FEM pdf of UM user s manual which is available in the um_root manual directory and in the Internet via this link http www umlab ru download 50 eng 11 um fem pdf It is supposed that you already studied the gs UM pdf manual which is devoted to basics of UM modeling and know how to create new model add new bodies and joints generate and compile eguations of motion UM Input and simulate mechanical systems UM Simulation The modal approach is used for simulation of dynamics of elastic bodies This approach consists in presentation of elastic deformations with the help of a set of eigenmodes and static modes The approach assumes describing elastic bodies in terms of finite element method in ANSYS software with subsequent export that data to UM Thus the necessary condition of using UM FEM is availability the ANSYS software for some preliminary analysis and calculations Every ela
13. _all directory contains graphical windows with reaction forces in the rest joints of the model as well as angular velocities of all cranks Universal Mechanism 5 0 31 Getting Started UM FEM 3 Electric motor on elastic platform Let us consider step by step dynamical analysis of a mechanical system that consists of an electric motor and an elastic platform Fig 3 1 i Figure 3 1 The elastic platform is connected to a ground with the help of four visco elastic linear force elements The electric motor 1s included to a model as an external subsystem and is also connected with the help of four visco elastic linear force elements Fig 3 1 An eccentric is attached to a rotor of the electric motor This eccentric produces forced oscillations of the platform Basic features of the description of the model and its dynamical analysis is considered in this section During the simulation we will analyze the following dynamical properties of the system e forces in the force elements e vertical displacements and accelerations of the platform in the center part under the motor Here we will simulate the following sequence of operation modes e running of the rotor from m 0 up to its nominal angular velocity e operating duty e stop way decreasing angular velocity of a rotor till o 0 Universal Mechanism 5 0 32 Getting Started UM FEM Preparing the model includes the following steps e preparing data of the elastic platform e
14. analyzing its dynamics Now we will create a new model From the File menu select New object MBS or click the button 3 2 1 Introducing elastic platform 1 Select Subsystems item in the tree of elements Create a new subsystem by dp clicking button 2 Set Type to Linear FEM subsystem New open dialog appears In this dialog select the platform directory You can see elastic modes using the Amplitude and Rate track bars on the Solution Modes tab 3 Set Name to Platform Fig 3 2 x Name z PE pe Type OH Linear FEM subsystem ext mmm Figure 3 2 3 2 2 Attaching the elastic platform to a base Platform is attached to a ground with the help of four visco elastic force elements that are situated at the edges of the platform Firstly we will create graphical objects for force elements and then create force elements themselves Universal Mechanism 5 0 37 Getting Started UM FEM 3 2 3 Creating graphical elements Now we will create graphical object for elastic force elements 1 Select Images in the tree of elements 2 Add new graphic object GO by clicking the button 3 Set name of the new GO to Spring Fig 3 3 x None Smo g H uz ext EOR Figure 3 3 dh 4 Add a new graphic element GE by clicking the at the lower panel Fig 3 4 Description GO position Figure 3 4 5 Select Parametric type in the pull down menu Fig 3 5 Description Go position
15. anges of identifiers will lead that found above set of coordinates will not correspond to equilibrium position any more In such a case you need to repeat the calculation of equilibrium position Universal Mechanism 5 0 53 Getting Started UM FEM 5 Select the Frequencies tab Natural frequencies of the model are calculated automatically Fig 3 23 6 You can see eigenmodes of the model in the animation window To see an eigenmode just select it in the list and click the Animate button Now you can see that the animation window shows any selected eigenmode of the model You can control the Amplitude and Rate of eigenmode animation To stop animation click the Stop button 7 Close the window of Linear analysis Linear analysis Ea Initial conditions Identifiers Uptions E guilibrium Frequencies Root locus Compute Animation of modes fe Natural frequencies Hz Amplitude C Eigenvalues Fate 71 5711 O E Animate Lui ema Figure 3 23 Universal Mechanism 5 0 54 Getting Started UM FEM Bb VEZO S O u Siu war ie s somi Figure 3 24 Animation of second eigenmode 24 11 Hz Universal Mechanism 5 0 55 Getting Started UM FEM 3 2 9 2 Integration of equations of motion 1 Open the Wizard of variables the Tools Wizard of variables menu command and create variables for Z components of linear force elements SpringMotorBR DamperMotorBR Fig 3 25 Bee Wizard of variables
16. ctory as a working directory 3 Run ANSYS 4 From the File menu select the Read Input from and open the platformshell63 ans file As a result a steel platform that is consists of two beams of Im length and a shelf between them This finite element model includes 886 elements of SHELL63 type Width of all elements is 5 cm You can open platformshell63 ans in any text editor and change some of parameters of the FEA model see comments in the body of this file Four nodes where the platform is connected with the ground are selected as interfaced nodes In the end the um mac is run If the um mac is not run automatically you should run it manually see Sect 2 1 As a result of the um mac execution 24 static modes and 10 eigenmodes are calculated 5 If the path to the ANSYS UM EXE in the um mac is set correctly see Sect 2 1 ANSYS UM EXE starts automatically Otherwise run ANSYS_UM EXE manually from the um_root bin directory 6 Transform data according the 5 8 items of the Sect 2 2 1 Universal Mechanism 5 0 35 Getting Started UM FEM 3 1 2 Wizard of elastic subsystems Working with the Wizard of elastic subsystems is described in the Sect 2 2 2 Now you should repeat all the instructions from the Sect 2 2 2 Use the Aplatform input fum as an input file for the Wizard Please note that the A platform input fss file should be created after all Universal Mechanism 5 0 36 Getting Started UM FEM 3 2 Creating the model and
17. definitio f Linear model C Damping ratio for each mode Damping ratio for each mode aleulate Frequency Hz Damping ratio Integration Integration Figure 2 28 10 Start simulation Integration button You can see movement of the mechanism in the animation window see Fig 2 29 and oscillograms of reaction forces in the graphical window see Fig 2 30 Animation window LE mf SO BL Ov Bull ae Z Figure 2 29 Animation window Universal Mechanism 5 0 29 Getting Started UM FEM Plots Reactions forces in joints Varables gi HFraliLrark Lorrrod Absolute value of reaction force in joint rank Lor rod gi RFrmljLor rod Slider Absolute value of reaction force in joint Lor rod Slider Figure 2 30 Graphical window In order to estimate the influence of the elastic con rod instead rigid one open the um_root Samples Flex Slider_crank_all model Graphs of the reaction force are shown in the Fig 2 31 Fe Plots Reactions forces in joints Vanables JRFro jCon rod rigud Slider Absolute value of reaction force in joint Con rod ngad Slider RErmljbeaml Slider3 Absolute value of reaction force in jomt jbeaml Slider3 Fa Figure 2 31 Reaction force in the Con rod Slider joint 1 con rod is a rigid body 2 con rod is an elastic body Universal Mechanism 5 0 30 Getting Started UM FEM Configuration file example icf which is situated in the Slider_crank
18. e0 and the crank crank and the con rod and the con rod and the slider e translational joint between slider and Basel 1 Create a new model Point the File New object MBS menu command or click the H button New constructor window appears Universal Mechanism 5 0 18 Getting Started UM FEM 2 3 1 Creating graphical objects 1 Load a graphical object from the um_root bin graph Basel umi file using button or Edit Read from file menu item Element NoName will be added to the list of graphic elements see Fig 2 13 l Et Object pa on K Object os P Subsystems Eb nages Figure 2 13 2 Select this element and set name to BaseO in the data inspector Fig 2 14 x Mene boso HP ue est S Figure 2 14 3 Repeat these actions for Crankl umi and Sliderl umi files which are located in the directory um_root bin graph Set the names Crank and Slider to created graphical objects correspondently Thus three graphical objects are created ig Object m FE Object E Subsystems i Images oi Basel amp Slider Figure 2 15 Universal Mechanism 5 0 19 Getting Started UM FEM 4 Select Object item in the tree of elements and set Scene image to BaseO see Fig 2 16 E Sensors LSC Varables Curves Object Options Path L YModelstzlider crank fe Object typ fe General Rail vehicle Equation generatia C Symbolic f Numeric lterati
19. f the end points of elastic element in undeformed state coincides with Electricmotor Body Y 0 07 Please draw attention to the rotation on 90 degrees about the X axis Fig 3 20 to make the orientation of SC of the force element coinciding with the SC of the Electricmotor Body Set the stiffness matrices of elastic force element as it is shown in Fig 3 21 Element matrix Element coordinate coordinat fcStifflateral Figure 3 21 Initialize the identifiers as cStifflateral 1 0E6 cStifflongitudinal 1 0E6 The corresponding values for the damping elements are cDisslateral 1 0E3 cDisslongitudinal 1 0E3 3 2 8 Preparing for simulation l Save the model as Vibrostand with the help of the main menu or the corresponding button 2 Generate and compile equations of motion if equations are generated in symbolic form If no errors detected the model is ready for simulation Universal Mechanism 5 0 DI Getting Started UM FEM 3 2 9 Simulation Let us compute the vertical components of forces in force elements coupling the electric motor and the platform when the rotor of the motor rotates with the constant angular velocity nu lt 1620 r p m As an example consider the rear right pair of elements Let us compute displacements and accelerations of a center of plate under the electric motor as well 1 Run the UM Simulation with the F9 key or by clicking the P button on the tool panel 2 Open a new animation window t
20. f the necessary type e g SpringFL in the case of a new elastic element 2 Click the button to create a copy Rename the copy e g SpringFR forward right A U Correct coordinates of attachment points For the SpringFR element we have Base0 BeamLensth 2 WidthShelf 2 WidthBeamShelfLow 2 0 05 Platform Platform BeamLength 2 WidthShelf 2 WidthBeamShelfLow 2 0 0 coordinates of the element end point in undeformed state in system of coordinates of the first body BeamLength 2 WidthShelf 2 WidthBeamShelfLow 2 0 0 Fig 3 10 Thus the full list of force elements connecting the platform with the base must include the following elements SpringFL DamperFL SpringFR DamperFR SpringBL DamperBL SpringBR DamperBR Universal Mechanism 5 0 44 Getting Started UM FEM 3 2 5 Model of electric motor We shall not create the model but use the ready model of an electric motor located in the um_root Samples Flex electricmotor directory 3 2 6 Adding motor to object as a subsystem ap 1 Select the Subsystems tab in the element list Add a new subsystem by the button 2 Select its type Included and open the um_root Samples Flex electricmotor model Fig 3 16 Open object x ocan directory CAProgram Files UM Software Labi g E ke CAFrogram Files UM software L electicmotor m slider crank all gi slider crank fem m vibrostand CAProgram FilestUM Software
21. gram ANSY S59 0 A Name of solution flexbeam 16 11 2005 23 50 40 Flexible beam with Modes 101 Finite elements 300 Degrees of freedom bUb Normal modes 10 static modes 12 Computation with lumped mass matrix Min natural frequency 26 67 Max natural frequency 355 07 Generalized mass matric present Generalized stiffness matrix present alll D Models flexbeam input urn Cancel Figure 2 5 General Position Image Solution Data file DAmodels flexbeamtinput fum B subsystem information Data prepared ANSY59 0 Name of solution General Position Image Solution flexbearmn Header of solution comments 16 11 2005 23 50 48 Flexible beam with masse element for definition torsion inertia moment Modes x 0 00000000 A x 000000000 4 x 0 co000000 B shit after rotation 101 300 bUb Finite elements Degrees of freedom Mormal modes Static modes Mormnalization Figure 2 6 Figure 2 7 Universal Mechanism 5 0 12 Getting Started UM FEM Using the Image tab we can change graphical representation of the FE model There are two modes of such a representation simplified and full During the full model status line shows the information about nodes and finite elements when mouse cursor is on it However the full mode takes more CPU time to animate 6 Set Image to full 7 Turn off the Image para
22. introducing FEA model of the platform into the final UM model e attaching the elastic platform to a ground e creating the model of the electric motor e introducing the electric motor into the final model as an external subsystem e attaching the electric motor to the platform with the help of visco elastic elements Let us consider all of the described above steps in details At that main attention will be put to the features that were not considered in the previous section It supposes that you already finished the previous section that is why some comments here are given shortly Please choose an existing or create a new directory for the future model Within this section we will address this directory as Create two subdirectories e AVibrostand for the final composite model e Vibrostand Platform for elastic platform Universal Mechanism 5 0 33 Getting Started UM FEM 3 1 Preparing elastic platform In terms of Universal Mechanism software every elastic body is considered as a separate subsystem of Linear FEM subsystem type Standard save file for such a subsystem is input fss file Preparing the elastic platform includes the following Steps 1 description the FEA model of the platform in ANSYS software 2 calculation of the elastic modes and export result from ANSYS in UM format There are two possible ways to fulfill the second step 1 generate the input fss file directly by ANSYS_UM EXE program 2 firstly gene
23. ion of the con rod There are following cases e con rod as a rigid body e con rod as a system of eleven rigid bodies interconnected by revolution joints with damping and elasticity e con rod as an elastic body according to UM FEM methodology see Sect 11 1 Figure 2 1 Slider crank mechanism 1 base 2 crank 3 con rod 4 slider The process of creating and simulating a hybrid model of the slider crank mechanism with elastic con rod is discussed in this section Preparing the model consists of the following steps 1 describing FEA model of the con rod in ANSYS 2 calculating elastic modes of the con rod saving data in UM format 3 creating graphical objects 4 describing bodies crank and slider 5 adding elastic con rod 6 creating joints and forces Steps 1 2 are done in under ANSYS environment 3 6 in UM Note UM uses subsystem technique to introduce elastic bodies into the model Every elastic body are represented as a separate subsystem of Linear FEM subsystem type Universal Mechanism 5 0 5 Getting Started UM FEM Create a directory for the future models Within this section we address this directory as This directory will include two subdirectories e flexbeam for an elastic beam data e slider_crank_fem for the hybrid model You can read this manual more or less detailed Please note the following remarks e If ANSYS software is available on your computer and you want to study all
24. line of the macros Set full path to the ansys um exe as the parameter of the sys command For example sys c um bin ansys_um exe Note 1 If the full path to the ansys_um exe program contains space s then use inverted commas For example sys c universal mechanism bin ansys_um exe Note 2 Path to the ansys_um exe program should contain the Latin letters only Universal Mechanism 5 0 7 Getting Started UM FEM 2 2 Preparing con rod as an elastic beam As it mentioned above preparing data for introducing elastic bodies into hybrid models contains the stage of solution of eigen values problem There are two possible mathematical formulations of this problem e with diagonal mass matrix e with consistent mass matrix The um_root Samples Flex flexbeam input directory contains two subdirectories lumped and consistent The first one includes an ANSYS command file for the case of diagonal mass matrix the second one for consistent mass matrix In the manual we will consider the case with diagonal mass matrix 2 2 1 Working under ANSYS environment 1 Copy the flexbeam amp mass21 ans file from the um_root Samples Flex flexbeam input lumped directory to the flexbeam directory This file is the ANSYS command file uses APDL language and describes the process of ANSYS model creation This file also contains comments that explain every step of the process 2 Run ANSYS Interactive and select the flexbeam director
25. meters draw nodes check box 8 Set the rest parameters according to the Fig 2 8 General Position Image Solution Imag simplified e full Image parameter Draw nodes MW Draw finite elements Contour Bounds are not visible SIZES Node image Bean curve width Single node FE Single node elements fe Beam elements Shell and plate elements Solid elements Polygons Additional Figure 2 8 Note Single node finite elements of the MASS21 type are used for setting moment of inertia of the body relative to the longitudinal axis Set Sizes Single node FE to 0 in order to hide such elements and make the image clearer Universal Mechanism 5 0 13 Getting Started UM FEM The Solution tab gives you a possibility to animate modes of elastic subsystem To start animation you should click the Animate button see Fig 2 9 You can control this animation with the help of Amplitude and Rate track bars You can include exclude any form from the final set of modes turning on off the corresponding check boxes in the Modes tab The more modes you include in the final solution and the more frequency these modes have the more accurate and time consuming subsequent numerical integration you have Generally it is recommended to turn on off modes to keep a balance between solution accuracy and time efforts for it Thus you can fulfill the only calculation in the ANSYS software with the maximum
26. modes you will ever use 10 in this example and then form various sets of modes with the help of the Wizard of flexible subsystems data Leave the initial set of modes without any changes Universal Mechanism 5 0 14 General Position Image olution Data se f Original O Transformed Modes Rigid body Intertace nodes 10 normal modes 12 static modes Selected normal modes 10 Selected static modes 12 normal 2 normal 26 668 3 normal 73 512 4 normal 3 512 5 normal 144 112 E normal 144 112 T normal 220 224 S normal 238 224 4 normal 385 866 10 normal 355 866 11 static 12 static 13 static 14 static 15 static Amplitude Rate E E Frame per 1 4 period 5 ti Animate Transformation Modes Shift SC Turing of SC I exclude rigid body modes frequency 0 300 t Transtorm Save as Figure 2 9 Getting Started UM FEM Universal Mechanism 5 0 15 Getting Started UM FEM 9 Turn on the Transformations exclude rigid body modes Fig 2 9 10 Set Transformations Frequency to 0 3 Fig 2 9 11 Click the Transform button and confirm this action in the subsequent dialog As a result the transformed set of modes of elastic body is created In the case of successful execution of the transformation the following message appears see Fig 2 10 UM Object data input 6 rigid body modes are deleted from the transformed data set
27. motor and come back to the composite model Universal Mechanism 5 0 49 Getting Started UM FEM 3 2 7 Electric motor and platform coupling by force elements Coupling the electric motor and the platform can be set quite similar to attaching the platform to the base Electricmotor Body and Platform Platform are interacting bodies An example of description of an elastic force element is shown in Fig 3 20 x Name SpringMotorEL a Ek me ext OZ Body Electricmotor Body Pato Plafom gej Flatfarrni Platform Platform Type E Viscous elastic Gu Spring v Position Parameters Compute for the nd body Automatic computation for 2nd body Body Body2 System of coordinates at pt BE 5LEZ a 140018 0 069 0 0E 0 06 S v 30 000000000 pA io OOOCODOI pA io OOOCODOI pA Figure 3 20 Table contains coordinates of attachment points of elastic and damping force elements realizing the coupling Table 1 Electricmotor Body Platform Platform Z SpringMotorFL 0 0156 0 053 0 069 0 0156 0 069 DamperMotorFL 0 015 0 015 0 015 0 015 SpringMotorFR 0 0156 0 053 0 1 0 015 0 0156 0 1 0 015 DamperMotorFR 0 015 0 015 SpringMotorBL 0 1 0 053 0 069 0 1 0 069 DamperMotorBL 0 015 0 015 0 015 0 015 SpringMotorBR 0 1 0 053 0 1 0 015 0 1 0 1 0 015 DamperMotorBR 0 015 0 015 Universal Mechanism 5 0 50 Getting Started UM FEM Coordinates X Z o
28. nitialize values of identifiers as Fig 3 12 BeamLength 1 0 WidthShelf 0 4 WidthBeamShelfLow 0 1 5 Coordinates of the element end point in undeformed state in system of coordinates of the first body Fig 3 10 BeamLength 2 WidthShelf 2 WidthBeamShelfLow 2 0 6 Select Body2 tab Set coordinates of element attachment points to the second body Platform Platform Fig 3 11 BeamLength 2 WidthShelf 2 WidthBeamShelfLow 2 0 xj Name RE JE nm NI Body Body Based Pitom Platform z Type E viscous elastic GU Spring v Position Parameters Compute for the 2nd body Automatic computation for 2nd body Body Body Sistem of coordinates at pt A SCA Ty pomi friars 005 7 o OOOOOCOO x in OOOOOOOO x E zd OOOOOOOO x PE A aa ESEM JJ B1 the end of element N Universal Mechanism 5 0 41 Getting Started UM FEM Figure 3 10 Body Bodye System of coordinates at pt B2 5LEz ESENC 0 000000 000000000 0 00000000 Figure 3 11 Initialization of values beamlength Add to the sheet Figure 3 12 5 Let us introduce a stiffness matrix of the element Select Parameters tab Click the i button in the Stiffness matrix box Fig 3 13 set diagonal elements of the matrix corresponding to the translational degrees of freedom Fig 3 14 and click OK Set the following identifier values cxx le 6 cyy 1le 6 czz 1e 6 N m Position Parameters
29. o visualize the simulation process Tools A nimation window 3 Use the Analysis Simulation menu command to open the Object simulation inspector 4 Use the FEM Subsystems Image tab of the Object simulation inspector to change the flexible platform image if necessary Universal Mechanism 5 0 52 Getting Started UM FEM 3 2 9 1 Calculating the equilibrium position and natural frequencies Let us calculate the equilibrium position of the stand 1 If the Objection simulation inspector is active close it by the Close button 2 From the Analysis menu select Linear analysis or press the F8 key Window of linear analysis appears 3 Select the Equilibrium tab Turn on the Keep coordinates and identifiers check box Start the calculation by the Compute button Fig 3 22 Calculation process might take some time Linear analysis Identifier Limits Lizeretizatian i Keep coordinates and identifiers Variable value of identifier Compute Parameters of process Process Calculation over e 3 619E 16 Figure 3 22 Now we need to save current coordinates which correspond to the found equilibrium position to a file of initial conditions 4 Select the Initial conditions tab Click the button and save current initial conditions to the equilibrium xv file Note Just found values of coordinates correspond to equilibrium position are correct for the current values of identifiers of the model only Any ch
30. on Image simplified e full Image parameters W Draw nodes W Draw finite elements Contour Bounds are not visible Size Node image Bear curve width Single node FE Figure 3 26 Now we will plot oscillograms of a position and acceleration of some arbitrary node of the platform 5 Select Wizard of variables and create two variables for calculation Z projections of position and acceleration of the node 956 with approximate coordinates 0 048 0 007 0 06 see Fig 3 27 3 28 Note You can plot position and acceleration of any node you want The only information you need is coordinates of the node To get them point the mouse to the node in an animation window and you can see its coordinates in the status bar of the window see Fig 3 27 6 Create two new graphical windows Tools Graphical window and drag and drop just created variables to these windows separately Universal Mechanism 5 0 o Getting Started UM FEM 4 Animation window Pijal FA B r e D 1 184 Node NS56 r 0 04810815 0 006908045 0 06 Figure 3 27 iji i Wizard of variables vibrastand User Expression Identifier All forces Joint force je Basel Coordinates Angular var ReactionF Linear vat Linear F gp Platform Bod a Plathorrn iad Elek em ot i Platform Platforrn 0 045 0 007 0 06 Relative to bod Fe RN Typ Resolved in SC of bod
31. on generatio Language far output file Autodetection O Peese Direct Composite body method W Coe Recommended method Direct i Compile equations Run simulation module i Generate all Close Figure 2 23 Now the model is ready for simulation Universal Mechanism 5 0 25 Getting Started UM FEM 2 4 Simulation 1 Use the menu command Object Simulation to run UM Simulation program Main window of the UM Simulation program appears Let s obtain reaction forces in the joints Crank_Con rod and Con rod_Slider 2 Open new animation window 3 From the Analysis menu select Simulation Object simulation inspector appears Select the FEM subsystems Image tab to set up animation parameters of the elastic con rod as you want Now we will calculate initial conditions 4 In the Object simulation inspector select the Initial conditions tab Select the Con rod subsystem in the drop down list Fig 2 24 An anchor sign means that the correspondent degree of freedom is frozen In this example it means that the elastic degrees of freedom will not be changed during calculation of initial position Note If the Initial condition tab differs to the Fig 2 24 set the anchors manually 5 Make sure that the Autocalculation of constraint equations mode is turned on the button should be pressed otherwise press this button Then calculate the initial conditions by clicking the button Animati
32. on window shows the current position of the mechanism Fig 2 25 Universal Mechanism 5 0 26 Getting Started UM FEM Solver Identifiers Initial conditions Object variables katri Information FEM subsystems Tools Coordinates Constraints for initials db o xi of Z ki slider_crank_fem Con rod FEM v b onae v Comment 2 0 Joint t 1 O 0 Joint t 2 O 0 Joint t 3 O O Joint a 1 O O Joint a 2 O O Joint a 3 O O Mode 1 O 0 Mode 2 O O Mode 3 2 10 O 0 Mode 4 2 11 O O Mode 5 212 ib 0 O Mode E 213 O O Mode 7 Message duz 0 1 zj da 0 1 i Integration Figure 2 24 ay Animation window Gl B 56 O SO mu a m 2 Figure 2 25 6 Open new graphical window Tools Graphical window menu command 7 Run Wizard of variables and create variables for reaction forces according to Fig 2 26 and drag them to the graphical window Universal Mechanism 5 0 27 E Wizard of variables ce slider_crank_fem User Expression All forces Basell_Crank Coordinates Angular var Reaction F Crank Con rod Con rod_Slider Joint Getting Started UM FEM ey Dee lider Conrod Slider a Con rod Type of variable G Force Moment Componen e a so e cv Resolvedin 5C of body SC Acts on body Conrod flexbear iRFm Con rod_Slider lt q Reactive force for joint Con rod_Slider magr a im JRFm Crank Cor rod JRFm Con rod_slider Figure 2 26
33. osing none Llosing none a b Figure 3 8 5 Add the second GE Cone and set its parameters as in Fig 3 8b 6 Go to the GE position tab and shift the element on 0 3 along Z axis the Translation z box 7 Set the diffuse component of the GE color by Diffuse button on the Color tab Fig 3 9 Cone Cone Type a Cone or o ext s GE position Material Parameters Color Hide Assign to all GE Dittuse Specular E E missive E Ambient Assign color from list Shines 4 v Visible sid O Both de Front C Back Wired Width of curves i pA Figure 3 9 The images are created Let us continue with the force elements Universal Mechanism 5 0 40 Getting Started UM FEM 3 2 4 Force elements Let us introduce several identifiers to set the attachment points e BeamLength the length of platform beams e WidthShelf the width of connecting shelf e WidthBeamShelfLow the width of lower shelf of beam section Let us start with the elastic element on the front left end of the platform beam 1 Select Linear forces in the object element list 2 Add a new force element by clicking the ri button 3 Rename it as SpringFL forward left set element type Elastic interacting bodies Base0 Platform Platform as well as the Spring GO Fig 3 10 4 Set coordinates of element attachment points to the first body Base0 BeamLength 2 WidthShelf 2 WidthBeamShelfLow 2 0 05 I
34. rate the intermediate input fum file by the ANSYS_UM EXE and then complete data transformations with the help of Wizard of elastic subsystems that is a tool within the UM Input program This wizard gives the user a possibility to visualize calculated elastic forms and exclude some modes from the final set of elastic modes input fss There are three files in the um_root Samples Flex platform input fss input fum and platformshell63 ans e If you want to omit the step of preparing the data in ANSYS but familiarize yourself with Wizard of elastic subsystems you should copy the um_root Samples Flex input fum file to the platform directory and go to the sect 3 1 2 of this manual e You may omit all the steps of creating the data of elastic platform in this case you should copy the um_root Samples Flex platform input fss file to the platform directory and go to the sect 3 2 of this manual Universal Mechanism 5 0 34 Getting Started UM FEM 3 1 1 Working under ANSYS environment Before you come to the next step please repeat all the steps from the sect 2 1 Now we will create the FEA model of the platform and export the data for the subseguent using them under UM environment 1 Copy the platformshell63 ans file from the um_root Samples Flex platform directory to the platform directory This file contains APDL commands that automatize creating the FEA model of the platform 2 Run ANSYS Interactive and select the platform dire
35. s in generalized linear force elements Varables lO F SpringM otorBL 2 Generalized linear force element 5 pringhotorBEL Force projection Z E imi F DamperhotorEL z Generalized linear force element D armperHotarBLJ Force projection Z ee eee aa a ee ae ee eee o m rnjj ii Hi H Oe 0 171 E Universal Mechanism 5 0 62 Getting Started UM FEM Plots Yalues of forces in generalized linear force elements Variables C Ii F SpringM otorBL z Generalized linear force element 5 pringhotorBL Force projection Z Ba F DamperhotorEL z Generalized linear force element D armperHotarBLJ Force projection Z et ga fee Figure 3 32 To estimate the influence of the platform flexibility the following operations could be done 1 The option switch off all flexible modes should be on Fig 3 30 2 Run simulation 3 Copy variables in graphical windows as static using popup menus contact menu in a graphical window Copy as static variables menu item 4 Change the option switch of all flexible modes to off Fig 3 30 5 Repeat the simulation 6 Compare simulation results
36. sscsssscesecenasvebcssveesevenesssscusteusexscoues Goustenesvecosssccessseseseseas 33 3 1 1 Working under ANSYS environment 34 3 1 2 Wizard of elasti MDS S O a a bee E a EE E EAE a ako deo 3 2 Creating the model and analyzing its CYNAMICS ccccssccccsscccssscrsssccssssccsssccesscoess 36 3 2 1 Initoducine e lastie platilor soricina n a E 36 OMA Attaching the elastic platform to a Dase ce cceccccsesecceeeeceeseeeeneeeaeeeeeeneeeeesesaeeeens 36 22 Credne SANMI NS a E E E elena 37 3 2 4 Porce O ee A E EA E E E V ae 40 Sn Model of electric MOtOT a o a a ea ba ea ono netetas enuaceeaneter 44 3 2 6 Adding motor to object as a subsystem ae a k lk a eh ia 44 3 2 6 1 Setting angular velocity of the rotor enee 46 o VONJA Electric motor and platform coupling by force elements 49 3 2 8 Pe ale TOP Snl oe aE E EEEE E 50 3 2 9 A a a E E E E E eo ee 31 3 2 9 1 Calculating the equilibrium position and natural freguencies 32 3 2 9 2 Integration of eguations of MOON ina ase pike ke oe kake dokaj 55 Universal Mechanism 5 0 4 Getting Started UM FEM 2 Slider crank mechanism Here the example model of the slider crank mechanism see Fig 2 1 is considered There is Slider_crank_all model in the um_root Samples Flex directory This model includes three slider crank mechanisms The difference between these models is in the way of representat
37. stems Tools Subsystem Flatform General Simulation Image Solution Options Damping Genera W Gravity Switch off all flexible modes Calculation of initial condition Fix modal coordinates Storr Store values of modal coordinates Deshnatiori fe hiema File Hile d madels wibrostand Platform Ire gl Integration Options Damping Getting Started UM FEM Object simulation inspector Solver Identifiers Initial conditions Object variables SE Information FEM subsystems Tools Subsystem Platform General Simulation Image Solution Dampin Z Internal dissipation Type of definitio e Linear model Damping ratio for each mode Linear mode Li zal EM Damping ratio for each mode alculate Frequency Hz Damping ratio rf Integration Figure 3 30 9 Select the Identifiers tab in the Object simulation inspector Select the Vibrostand Electricmotor from the pull down list of subsystems Set the following values Fig 3 31 e nu 1620 27 revolutions per second e tstart 0 5 e tspeeding up 2 e tworking 3 e tbraking 4 Note Rotational speed of the rotor exceeds two first natural frequencies of the vibrostand that is why there will be resonance conditions during speeding up the rotor Universal Mechanism 5 0 60 Getting Started UM FEM Object simulation inspector rformaticr FEM subsystems Tools Solver Identifiers
38. stic body is considered as a separate subsystem Data file of the elastic subsystem is a binary input fss file This file may be created with the help of ANSYS_UM EXE program or with the help of Wizard of elastic subsystems in the UMInput exe In the latter case ANSYS_UM EXE creates intermediate uminput fum that contains input data for the Wizard After ANSYS_UM EXE creates input fss or input fum files the subsequent preparing of the model is fulfilled with the help of Universal Mechanism Since the data files about elastic body is exported from the ANSYS software and prepared by ANSYS_UM program ANSYS software is not used any more Complete data flow from ANSYS to UM is shown in the eleventh part of UM user s manual partl1 pdf Thus using UM FEM module is possible if ANSYS software is available on the user s computer 1 http www umlab ru download 50 eng es um pdf Please find more detailed information about static modes and eigenmodes in the eleventh part of UM user s manual 11_UM_FEM pdf Universal Mechanism 5 0 2 Getting Started UM FEM Note 1 Before coming to the rest part of the manual please check if the UM FEM module is available on your computer Run UM Simulation and from the Help menu select About The list of available modules is shown in the Configuration section 2 Please also check if the ANSYS software is available on your computer If you do not have ANSYS on your computer you will have to leave some parts
39. t fum file On the successive step we will use the Wizard of elastic subsystems to convert the data into UM compatible form Creating data set for simulation of flexible body General Options I exclude rigid body modes Teguency 0 500 E Process cose Figure 2 3 Universal Mechanism 5 0 9 Getting Started UM FEM Note Using the Wizard of elastic subsystems is not necessary step of the creation of the model However it seems to be very important for your understanding UM that you go through the Wizard It possible to prepare all necessary data with the help of ANSYS_UM program only To do this you should turn on modes normalize and exclude rigid body modes check boxes and set frequency In this case the input fss file will be created Please read eleventh part of UM User s Manual for more detailed information 7 Click the Create button Calculations will take some time The flexbeam input fum file will be created as a result 8 Click the Close button Universal Mechanism 5 0 10 Getting Started UM FEM 2 2 2 Wizard of elastic subsystems During the next step we will use the wizard of flexible subsystem data It is a tool for animation of elastic modes and exclusion of some of them Note Using the wizard of flexible subsystem data is not an obligatory phase Preparing the data can be fulfilled with the help of ansys_um program To do this point to the Options tab and turn on the normalize modes and
40. ta inspector looks like the wizard of flexible subsystem data described in the sect 2 2 There are following differences between wizard of flexible subsystem and the window of elastic subsystem data e You cannot changes set of modes in the window of elastic subsystem data since all data is already prepared e The Position tab influences to the real position and orientation of the elastic body in contrast to wizard of flexible subsystem where Position tab influences on the graphical representation of the body Elastic modes of the subsystem you can see using the Solution Modes tab x Name Con rod FEM mite tet Type JE Linear FEM subsystem mmm emi mm Figure 2 18 Universal Mechanism 5 0 22 Getting Started UM FEM 2 3 4 Creating joints Let s create the first joint revolution joint between Base0 and the crank 1 Select Joints item of the tree of elements Add new joint 2 Rename the joint to Base0 Crank Select Rotational type for the joint and set Y axis as Joint vectors see Fig 2 19 x Hare B ase Lrank uta gi x Body Body OO Basel Crank Type EI Rotational ki Geometry Description Joint force Figure 2 19 Universal Mechanism 5 0 23 Getting Started UM FEM 3 Select the Joint force tab set Joint torque to Expression and in the field Description of force set F torque cdiss_crank v see Fig 2 20 Press Enter The window Initialization of values for new identifiers
41. the data flow in details you should read this manual sequentially e If ANSYS software is not available or you want to omit the step of preparing data in ANSYS you can directly start from the sect 2 2 2 of this manual Before that you should copy the um_root Samples Flex flexbeam input fum to the flexbeam directory e You can omit all the steps of elastic body data preparing Before that you should copy um_root Samples Flex flexbeam input fss to the flexbeam and start reading from the sect 2 3 of this manual Universal Mechanism 5 0 6 Getting Started UM FEM 2 1 Preparing ANSYS environment We will use ANSYS software for preparing data for simulation of dynamics of elastic body After creating FEA model a calculation of the static and eigen modes starts Macro um mac is used for such a calculation Then ANSYS_UM program starts This program translates data that are produced by um mac into UM format Copy the um mac file from um_root bin to ANSYS default directory for macros It is usually the docu directory in ANSYS 5 0 apdl in ANSYS 7 0 9 0 root directory Otherwise you need to set search path with the ANS YS command PSEARCH Path_to_macro After preparing data the um mac macros runs the external ansys_um exe program for subsequent analysis of obtained data The ansys um exe is situated in the um_root bin directory You need to open the um mac in any text editor and edit the path to the ansys_um exe program in the last
42. ve Direction of gravit Characteristic size i ILI pA Scene Image Basel r Figure 2 16 Universal Mechanism 5 0 20 Getting Started UM FEM 2 3 2 Creating rigid bodies Here we create slider and crack as rigid bodies set graphical objects for them and set their inertia parameters 1 Select Bodies in the tree of elements 2 Add two new bodies 3 Rename bodies with Slider and Crank and set the correspondent graphical objects Slider and Crank 4 Select the Parameters tab and turn on the Compute automatic flag for the both of bodies Inertia property of the bodies are computed automatically see Fig 2 17 x Name of ght s ext Mae Oriented points Vectors 30 Contact Parameters Position Points Go to element E Image M Visible Crank W Compute automatic Inertia parameter Added mass matris none EJ Coordinates of center of mas pu TO TO Figure 2 17 Universal Mechanism 5 0 21 Getting Started UM FEM 2 3 3 Creating elastic subsystem Now we introduce the elastic con rid in the model Every elastic body within a hybrid model is represented as elastic subsystem 1 Select the Subsystems item of the tree of elements and create new subsystem using the r button 2 In the Type select Linear FEM subsystem and choose the flexbeam directory in the open dialog window 3 Set Name to Con rod FEM Fig 2 18 After reading elastic subsystem da
43. y se Mi Cy O wiz O al fe a pi Componer Ics tovo tf Z o s a z Platform Acceleration of point 0 048 0 007 0 06 of b Sa 7 r z Platformn a z Platfarmn ki o S gi a a Figure 3 28 Universal Mechanism 5 0 58 Getting Started UM FEM 7 Set the solver parameter on the Solver tab of the inspector as in Fig 3 29 e Solver Park e Type of solving Range Space Method RSM e Simulation time 10 0 e Step size 0 002 e Error tolerance 1E 8 e Computing Jacobian Matrices ON always for flexible subsystems e Block diagonal matrices OFF Object simulation inspector katri Informatior FEM subsystems Tools Solver Identifiers Initial conditions Object variables Simulation process parameters Solver options Type of solyvin Null Space Method f Range Space Method Simulation time fi 0 000 ti Step size for animation and data storage 0 002 Error tolerance fi E 000 Delay to real time simulation i Computation of Jacobian Block diagonal Jacobian Keep decomposition of iterative matrix Integration Figure 3 29 8 On the FEM subsystems Simulation tab switches gravity internal dissipation as well as linear model should be ON Set a 0 001 b 0 Fig 3 30 Universal Mechanism 5 0 Object simulation inspector Solver Identifiers Initial conditions Object variables SE Information FEM subsy
44. y as working directory and set Working directory to flexbeam for example d models flexbeam 3 Run ANSYS From the File menu select Read Input from and choose flexbeam amp mass21 ans Steel beam of 2 m length and square cross section with 2 cm width is created Finite element model consists of 100 elements of BEAM4 type and 200 elements of MASS21 type Two end nodes are automatically selected as interface nodes If you made all setting ANSYS environment correctly then the um mac macros is started automatically and calculates 12 static modes and 10 eigenmodes of the beam 4 If you changed path to the ansys_um exe program in um mac properly then um mac runs ansys um exe automatically Otherwise run the um_root bin ansys_um exe manually The main window of ansys um appears Fig 2 2 5 Point to the General tab The ANSYS results file rst set to flexbeam flexbeam rst Target directory set to flexbeam see Fig 2 2 More detailed information about interface nodes you can find in the eleventh part of UM User s Manual Universal Mechanism 5 0 8 Getting Started UM FEM General Options ANSYS results file rst D madels flexbeam tlexbeam rst Target directory D eimulationtlexbearn c Process Lreate Llose Figure 2 2 Main window of the ANSYS UM program 6 Point to the Options tab and turn off the normalize modes check box Fig 2 3 This case corresponds to creating the intermediate inpu
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