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1. El Format En Filter Select Clipboard J Alignment ji Number _ Styles _ JEE Editing E 2 3 4 1600 in EA Ta 5 440025 9 1 b DEG 98882 9 1 6 284337 359 9 b DEG 63896 359 9 7 E ES 9 45 n 2 05 1 77 10 32 15 11 14 17 1437 12 2600 13 in 17 91 28 14 8 86 15 4 92 16 17 ft lb 1 00 RIGID RIGID FIGURE 1 3 PStress Postprocessing stresses in the critical area of the pulley in Goodman Diagrams found on the Pulley GD worksheet This concludes our brief overview of the PStress software A deeper review of the input data required by and the output data produced by this software appears in successive chapters Chapter 2 Defining a Pulley in PStress 2 1 Pulley Shape PStress is designed to compute the stresses in CEMA Engineered Class pulleys with T Section end disks like the one shown in Figure 2 1 F Dist Weld to Disk N LA Z FIGURE 2 1 PStress Pulley Schematic Chapter 2 Defining a Pulley in PStress 6 PStress assumes that the end disk is symmetrical It also assumes that the fillet radii end tangent to the horizontal If the fillet between the hub and the end disk is not tangent to the horizontal where the end disk meets the hub than2. This allowed us to preserve the speed of the close form analytical analysis while adding the ability to model complex geometries Xiangjun Qiu and Vinit Sethi published CDI s new simulation method and comparisons between our method and full ANSYS simulations in a paper titled A New Pulley Stress Analysis Method Based on Modified Transfer Matrix This paper appeared in Bulk Solids Handling volume 13 issue 4 PStress V3 2 3 calculates stresses that can be used for fatigue analysis at various loca tions that are provided as inputs to the program Two Fourier approximations are used to describe the loading on the pulley One Fourier series is used to describe the load ing in the tangential direction while a second Fourier series is used to approximate the loading distribution in the axial direction The advantages of this program include its ease of use coupled with a short execution time making it a valuable design tool which allows the designer to review the effect of a design change on the stress distribution in a short period of time Chapter 1 Introduction 2 1 2 Getting Started in PStress This section gives an overview of how to solve for the stresses in a pulley using PStress and how to process the output file to quickly determine if the pulley design is acceptable We begin by opening PStress and entering the dimensions of the pulley and shaft as well as the forces on the pulley Open PStress and enter the pulley properties
3. DESCRIPTION Conveyor Pulley X GENERAL REMARKS orem Epsum I A EE Ee a eee A A A A A rn LEE O INPUT SPECIFICATIONS BELT BELT WIDTH INCHES l 47 24 TENSION T1 POLAR ANGLE x J 67892 0 00 TENSION T2 POLAR ANGLE LBS DEG a 67892 2 00 l RIM DIAMETER INCHES sl 43 31 THICKNESS GINCHES econ ce e eee eee oes 0 98 DISC THICKNESS AT HUB FILLET RADIUS INCHES 1 97 2 01 THICKNESS AT RIM FILLET RADIUS INCHES 1 18 0 98 SHAFT DIAMETERS AT DISC CENTER INCHES I 12 64 12 64 CENTER DISTANCES BEARING DISC INCHES l 62 99 47 32 HUB DIAMETERS INNER OUTER INCHES l 15 94 23 66 WIDIH INCHES 02 l 6 30 DOCK DEV SONS TNHCHES oo on o nenn cc dese s se eens a l 4 33 NOMINAL LOCKING PRESSURES SHAFT HUB PSI l 15084 9718 NOMINAL MAX TRANSMISSIBLE TORQUE FT LB 140137 CONTACT PRESSURE MULTIPLIER DEVICE TYPE I 1 000 SHORT OUTPUT SPECIFICATIONS GENERAL WRAP ANGLE DEG I 182 00 m Opened D Work AndysCode PStress V3 2 3 Save File Test Overland Pulley 1 in L FIGURE 1 2 PStress Results Summary Screen In the current version of PStress the data on the summary page is always scaled to English units
4. UTS 724 2411 321 0 Ys 303 Ys 303 Ys 566 3 21 321 0 Endurance 62 Endurance 62 Endurance 114 601 321 y 5 680 321 0 i 6 750 250 100 7 790 250 0 i BRG 200 250 y 9 851 250 11 M 10 900 240 0 11 910 0 d _ Saved D Work AndysCode PStress V3 2 3 Save File Test Overland Pulley 1 in FIGURE 1 1 PStress Input Screen After entering all the data shown in the Figure 1 1 save the file by selecting Save as from the File menu Once the file is saved click the Simulate Pulley button on the tool bar just below the file menu This will run the PStress pulley solver Two black windows may or may not flash momentarily on the screen If the data was correctly entered the solution should converge in less than a second Now click the Summarize Chapter 1 Introduction 3 Results tab If the data was correctly entered and PStress install properly you should see the screen that appears in Figure 1 2 If so congratulations PStress was successfully installed E Di gt File Edit Help Simulate Pulley Input Summarize Results Full Results EN 4 I CLIENT ABC Pvt ll COBRVETVOR DERAM Tie Ss TDC PAGE NO J JOB NUMBER 1111 WEST HOLLY ST BELLINGHAM WA 98225 I DATE OCT 2i 3 l DESIGNER John Doe PSTRESS V3 2 PULLEY STRESSES ANALYSIS I z HO 4 4
5. exactly as they are shown in Figure 1 1 Note The PStress input screen supports three languages English Spanish and Portuguese To change the default input screen language select Preferences from the Edit menu This will open the preferences dialog box which allows the user to set a default language Pstress V323 y ios File Edit Help Simulate Pulley Input Summarize Results Full Results IDENTIFICATION LOADING INFO DISK GEOMETRY 3 i Diameter Thi Cent ABC Pvt Belt Width 1200 Entry Angle 0 er ee Designer John Doe Tension In 301 Wrap Angle 182 4 200 gt Tension Out 301 a Project T 3 1050 30 Description Conveyor Pulley X Overhung Force X 0 a Driven Both Sides aq 0 7 Clockwise j Remarks Lorem Epsum Overhung Force Y 0 5 0 0 f Alii Overhung Moment X 0 6 0 0 Overhung Moment Y 0 7 0 0 E p LOCKING DEVICE 20 e Dist Weld to Disk 80 Hub Fillet Radius 51 OD 601 Series Bikon 1015 1 U ed Face Width 1400 Rim Filet Radius 25 ID 405 10 0 Size 320x405 is OD 1100 Radial pts lt 10 3 Width 160 an re 104 SHAFT DIMENSIONS Thickness 25 CHAT A Adal Fillet ya Hub Pressure 67 Length Diam Radius Material 44yy Material 44yy y Material 4140 HT4SR y transmissible Torque 190 1 321 UTS 449 UTS 449
6. pulley and the Outside column refers to the exterior of the pulley In the summary file the following nomenclature is used SIGMAR Radial stresses SIGMAP Tangtial stresses SIGMAZ Axial stress TAURP Shear stress hub Disk locking device TAUZP Shear stress Rim 3 2 Fatigue Analysis using a Goodman Diagram As the pulley rotates the rim and the disk are subject to fluactuating stresses which can cause high cycle fatigue failure in these parts The Goodman diagram is used to determine is the various parts of the pulley will fatigue to failure This diagram is shown in Figure 3 1 To use this diagram we define the following parameters Omin minimum stress Omar Maximum stress Ca stress amplitude Omaz min 2 Om stress mean Omax Omin 2 The Goodman Diagram shows all the strengths and limiting values of the stress compo nents for a particular mean stress Failure is defined by the heavy outline The endurance limit strength Se is the point at which fatigue failure will not occur regardless of the number of cycles of loading applied to the part The value of Se is a Chapter 3 Interpreting PStress Results 10 su Sy Sy Su Mean stress FIGURE 3 1 Goodman Diagram function of material properties discussed in the previous chapter the manufacturing processes the operating environment and the design of the part In addition to the
7. the shape of the fillet will need to be manually defined using multiple points in the Disk Geometry section PStress will interpolate between disk thickness values using a power function Note to define multiple points in the Disk Geometry section the Radial pts lt 10 value must be incremented in the Disk section 2 2 Material Properties The default materials known to PStress are listed in the materials txt file found in the PStress installation folder This file is a text file which the user can edit to add additional materials The Ultimate Tensile Stength and the Yield Strength of the materials in a pulley are usually easy to find However the endurance limit is not usually listed in suppliers tables The PStress solver does not use endurance limit to compute the stresses in the pulley However this number is used by PStress to predict the onset of fatigue CDI recommends using the following endurance limits Se when evaluating pulleys Disk and Hub The endurance limit strength is 24 of yield strength in base metal and 18 of yield strength in welded zones Rim The endurance limit strength is 15 of yield strength note there is a butt weld across the entire face of the pulley which will rotate through all high stress regions 2 3 Shaft Geometry The shape of the pulley shaft is defined by the table in the lower right hand corner of the Input tab Axial Length is th
8. However much of this sheet can be converted to metric units using a spreadsheet provided in your PStress installation Before converting the summary file it must be saved to your hardrive Selected the Save option from the File menu to ensure that all the simulation results are saved Next from the Windows Start menu select the CDI folder and open the Goodman Diagrams Excel spreadsheet The spreadsheet shown in Figure 1 3 should appear Note to use this spreadsheet you must enable macros If you do not see the green button shown in Figure 1 3 make sure the work sheet you are displaying is Pulley Stresses and scroll to the top right To load the summary data into the excel spreadsheet click the green button Navi gate to the folder where the pulley data was saved and select the filename with the summary out appended to the end The speadsheet should load the summary of the pulley results and convert the stresses to metric units It will also plot the oscillating Chapter 1 Introduction 4 EEE a ta ied I Goodman Diagrams Compatibility Mode Microsoft Excel 2 lat Home Insert Pagelayout Formulas Data Review View Team 7 x a amp Arial MS gt E Si General 7 FE Conditional Formatting gt 3 Insert j 7 Aa a a pe gt 33 Format as Table 3 Delete Paste BZ u EE ie Sort amp Find amp ERS u B 3 EE E Cell Styles
9. PStress Pulley Stress Analysis Software Users Manual Issued October 29 2013 For PStress V3 2 3 CONVEYOR DYNAMICS INC 1111 West Holly St Bellingham WA 98225 USA Phone 1 360 671 2200 Contents Contents Symbols 1 Introduction La Wian te Petree no ook ee hae hE D RD ED ee ee Hwee ee me G 1 2 Getting Started in PhStress o soo cosacos aoe rea une a cirie ee i 2 Defining a Pulley in PStress ool Pulley obop eos a e a A EOE a d ew et ade 2 2 Material Properties c eoo tes berare a seda aig r a ea a 23 Bhatt Geometry sace rera eRe GEE a pe Eb gea a e Ya 3 Interpreting PStress Results al Pohes Output SIME oo soca See aa ea ee g 3 2 Fatigue Analysis using a Goodman Diagram oaoa o a Symbols Or a 8 pps Stress in Radial Direction Stress in Tangential Direction Stress in Axial Direction Shear Stress Ultimate Tensile Strength Yield Strength Endurance Limit Strength gee Se oe ee eet UU UU oe 2 Zg TD y y y lt z T T A OS 182 Chapter 1 Introduction 1 1 What is Pstress PStress is a proprietary program developed at CDI The first version was created in 1984 This version used a closed form analytical method to solve for the stresses in a pulley The program was based on the work of H Lange 1963 and W Schmoltzi 1974 In 1993 CDI expanded the number of shapes PStress could model by added a relatively small number of finite elements to the pulley simulation
10. e distance from the center of the shell to the feature being defined The 4th row of the table always specifies the location of the pulley end disk The 8th row always specifies the location of the bearing Turndown fillet radius end at the dimension specified in the axial length column An illustration of the shaft dimension locations appears in Figure 2 2 Chapter 2 Defining a Pulley in PStress BEARING R10 PULLEY 8 FIGURE 2 2 PStress Shaft Schematic Chapter 3 Interpreting PStress Results 3 1 PStress Output Summary The PStress output summary contains the following results of the pulley stress analysis 1 2 Input Specifications Output Specifications Total Torque d Bending Moment Locking Device Slip Check Stiffness of the various pulley components Principal Stresses Locations of largest range of principle stresses and the max and min stress at these locations used in fatigue analysis Shaft at each of the 11 locations specified in the input file 8 Chapter 3 Interpreting PStress Results 9 Bending Moment Torque Transverse Force Shear Stress Transverse Shear d Bending Stress Max Shear Max Von Mises Stress The stresses are tabulated for both sides of the pulley component surfaces In PStress the Inside column refers to the interior of the
11. fatigue stress checks CDI recommends adopting the following maxi mum stress limits Disk and Hub The maximum combined stress should not exceed 70 of yield Rim The maximum combined stress should not exceed 50 of yield
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