AbaqusCAECONTW05QInterfFit.docx

1、AbaqusCAECONTW05QInterfFitNote: This workshop provides instructions on using contact interactions in terms of the Abaqus GUI interface. If you wish to use the Abaqus Keywords interface instead, please see the “Keywords” version of these instructions. Please complete either the Keywords or Interactiv

2、e version of this workshop.IntroductionThis workshop simulates the interference fit of two circular rings. The model is shown in Figure W51. Both rings are assumed linear elastic and are modeled with CPE4 elements. Frictionless contact is assumed. The inner ring is overclosed relative to the outer r

3、ing by a constant radial distance of 0.05 units. Three analyses are performed. They differ in how the surface adjustments are applied and whether surface smoothing is employed. Figure W51. Model undeformed configurationPreliminaries1. Enter the working directory for this workshop./contact/interactiv

4、e/interference 2. Run the script ws_contact_interf.py using the following command:abaqus cae startup= ws_contact_interf.py.The above command creates an Abaqus/CAE database named circ-rings.cae in the current directory. The geometry, mesh, and material definitions are included in the model. You will

5、add the necessary data to complete the model, run the job, and finally postprocess the results.Configuring the AnalysisThe analysis consists of two general static steps. The steps will consider geometric nonlinearity. In the first step the interference fit will be resolved; in the second step, the i

6、nner ring will be rotated 360 while the outer ring remains fixed.To create general, static analysis steps:1. In the Model Tree, double-click Steps.2. In the Create Step dialog box:a. From the list of available general procedures, select Static, General if it is not already selected, and click Contin

7、ue.3. In the Edit Step dialog box:a. In the Basic tabbed page, toggle on Nlgeom.b. Enter the following description: resolve interference fit.c. Switch to the Other tabbed page and choose the Unsymmetric matrix storage scheme. (The unsymmetric solver is recommended for general contact.)d. Click OK to

8、 create the step.4. Create a second general analysis step:a. Enter the following description: rotate inner ring.b. Switch to the Incrementation tabbed page and set the initial increment size to 0.05. c. Click OK to create the step.Defining contact propertiesFrictionless contact is assumed between th

9、e parts. Use the penalty constraint enforcement method with the default penalty stiffness.5. In the Model Tree, double-click Interaction Properties.a. Name the property noFric and select Contact as the property type.b. In the contact property editor, select MechanicalNormal Behavior.c. Select Penalt

10、y as the constraint enforcement method.Part 1: Analysis with surface smoothingThe first analysis in this exercise considers the effects of surface smoothing on the solution. Here general contact will be used with a non-default contact initialization setting so that initially overclosed nodes are tre

11、ated as interference fits.Begin by defining the general contact definition.6. In the Model Tree, double click Interactions. 7. In the Create Interaction dialog box, name the interaction gc and select the Initial step.a. Select General contact (Standard) as the type and click Continue.b. In the Edit

12、Interaction dialog box, select noFric from the list of available Global property assignment options. c. In the interaction editor, click Create next to Initialization assignments. d. In the Edit Contact Initialization dialog box that appears, name the property fit-1. In the Initial Overclosures regi

13、on of the dialog box, select Treat as interference fits, as shown in Figure W52. e. Click OK to accept the selection and close the contact initialization editor. Figure W52. Contact interference option8. In the interaction editor, click Edit next to Initialization assignments. Select the surface pai

14、rs that will be adjusted, as indicated in Figure W53. Note that after selecting an item in each column on the left side of the dialog box, you will need to click in order to add the selections to the table on the right side of the dialog box. This assignment will cause all initially overclosed nodes

15、 to be resolved using an interference fit.Figure W53 Initialization table.9. Click OK to accept the selections and close the initialization assignment editor.10. In the interaction editor, switch to the Surface Properties tabbed page. Click Edit next to Surface smoothing assignments, as shown in Fig

16、ure W54.Figure W54 Surface property options.11. In the dialog box that appears, note that the option to smooth the surfaces is selected by default, as shown in Figure W55.Figure W55 Surface smoothing options.12. Click OK to accept the selection and close the surface smoothing assignment editor.13. C

17、lick OK to close the interaction editor.The contact interactions are now complete.Defining constraints and boundary conditionsYour next task is to define the constraints and boundary conditions that will act on the assembly. In the first step of the analysis, both rings are held fixed; in the second

18、 step, the outer ring is held fixed while the inner one is rotated. A distributing coupling constraint is used to transmit the rotation to the inner ring.Defining a distributing coupling constraint1. In the Interaction module toolbox, click the reference point tool to create a reference point. Locat

19、e the point at the origin (0,0).This point will be used to apply the rotation to the inner surface via a distributing coupling constraint.14. In the Model Tree, double-click Constraints to create a new constraint.15. In the Create Constraint dialog box that appears, select Coupling as the type and c

20、lick Continue.16. In the viewport select the reference point created earlier as the constraint control point; select the inner surface of the inner ring as the surface to be constrained.17. In the constraint editor, set the coupling type to Distributing. Accept all other defaults and click OK.Defini

21、ng the boundary conditions18. In the Model Tree, double-click BCs to create a new boundary condition. 19. In the Create Boundary Condition dialog box, select Displacement/Rotation as the boundary condition type and Initial as the step in which to apply the boundary condition. Name the boundary condi

22、tion fix-y and click Continue. 20. Click Sets in the prompt area to access the Region Selection dialog box. Select Fix-y. 21. In the Edit Boundary Condition dialog box, select U2 click OK to close the dialog box.22. Using a similar technique, define a boundary condition in the Initial step named fix

23、-x to the set Fix-x (select U1).23. Using a similar technique, define a boundary condition in the Initial step named refPt to the reference point (click Select in Viewport in the prompt area to select the point directly; select U1, U2, and UR3).24. Edit the refPt boundary condition in the second ste

24、p and set the value of UR3 to 2*pi.Creating and submitting a job for analysisNow you are ready to create and submit the model for analysis. 25. Create a job named interf-smoothing. Enter any suitable job description. Accept all other default job settings.26. Submit the job for analysis. While the jo

25、b is running, monitor its progress. Visualizing the analysis resultsAfter the analysis is complete, you will review the results in the Visualization module.27. Switch to the Visualization module, and open the output database file interf-smoothing.odb.28. Click to plot the Mises stress, as shown in F

26、igure W56. In this figure some nodes on the inner ring have been highlighted to allow us to track the rotation. Figure W56. Mises stress distribution with smoothing at end of interference fit step29. Animate the solution history. Figure W57 shows the configuration when 25%, 50%, and 75% of the rotat

27、ion has been applied. Note the position of the highlighted nodes in each case and how the contours of Mises stress remain smooth and constant throughout the entire simulation. This is the expected result since the sliding between the surfaces occurs in the absence of friction. Figure W57. Mises stre

28、ss distribution with smoothing at three different configurations during rotation stepPart 2: Analysis without surface smoothingHere general contact will be used as before. This time, however, the default option to smooth surfaces will be toggled off.30. Copy the model named smoothing to one named no

29、-smoothing.31. Edit the general contact interaction to toggle off the surface smoothing option.32. Create a job named interf-no-smoothing. Enter any suitable job description. Accept all other default job settings.33. Submit the job for analysis. While the job is running, monitor its progress.34. Aft

30、er the analysis is complete, evaluate the results in the Visualization module. The Mises stress at the end of the first step is shown in Figure W58. Note the noise in the solution. The beneficial effects of geometric surface smoothing are clearly evident when compared to the earlier solution.Figure

31、W58. Mises stress distribution without smoothing at end of interference fit stepPart 3: Analysis using contact pairs with precise adjustmentsHere contact pairs will be used instead of general contact. A combination of strain-free initial adjustments plus direct user specification of the interference

32、 distance will be used. This technique is particularly useful when you are not sure of the interference required or wish to perform a parametric study. Rather than create a distinct mesh for each value of interference, the same mesh is re-used and the overclosure value is specified directly. 35. Copy the model named smoothing to one named adjust.36. Delete the general contact interaction created earlier.37. Define the following surfaces: