Workshop15 rolling-plate

13

Click here to load reader

  • date post

    13-Sep-2014
  • Category

    Education

  • view

    727
  • download

    2

description

abaqus Workshop

Transcript of Workshop15 rolling-plate

Page 1: Workshop15 rolling-plate

Workshop 15

Single Pass Rolling of a Thick Plate

IntroductionRolling is a basic manufacturing technique used to transform preformed shapes into aform suitable for further processing. The rolling process is essentially quasi-static becauserolling is normally performed at relatively low speeds (typically 1 m/s) and, therefore,inertia effects are not significant.Representative rolling geometries generally require three-dimensional modeling, resultingin very large models, and include both nonlinear material behavior and nonlinearboundary effects (contact and friction). For this reason the explicit dynamics approach isoften less expensive computationally and more reliable than an implicit quasi-staticsolution if mass scaling is used.This workshop involves simulating quasi-static rolling of a plate using ABAQUS/Explicit.The rolling process reduces the thickness of the plate by 45% in a single rolling pass.Mass scaling will be used to reduce the solution time for analysis. For the purpose ofcomparison, the simulation will also be performed using the implicit solver available withABAQUS/Standard.This workshop is based in part on ABAQUS Example Problem 1.3.6.

Geometry and modelA half-symmetry plane strain model will be used with the plate having a length of 0.92 mand a half-thickness of 0.02 m. A 90 segment of the roller is constructed as an analyticalrigid surface.

1. Start a new session of ABAQUS/CAE from the workshops/rollingdirectory.

2. Switch to the Part module.A default model name is assigned by ABAQUS/CAE (Model-1). However, since theexplicit dynamics model will later form the basis of the implicit analysis model, youshould rename the current model to give it a more descriptive name.

3. From the main menu bar, select ModelRenameModel-1. Rename themodel Explicit.

4. From the main menu bar, select PartCreate. Name the part plate, choosethe modeling space as 2D, and set the approximate size of the sketch area to0.25. Review the other defaults, and click Continue.

5. Using the Create Lines: Rectangle tool, sketch a rectangle 0.092 m longand 0.020 m high, as shown in Figure W15–1.

Page 2: Workshop15 rolling-plate

Figure W15–1. Plate geometry

6. From the main menu bar, select PartCreate. Name the part roller, choosethe part type as Analytical rigid, the modeling space as 2D, the base feature asPlanar wire, and set the approximate size of the sketch area to 1.0. Reviewthe other defaults, and click Continue.

7. Using the Create Isolated Point, create two points with the coordinates (-0.170, 0.170) and (0, 0.170).

8. Using the Create Arc tool, sketch a 90 arc centered at the point (0, 0.170), asshown in Figure W15–2.

Figure W15–2. Roller geometry9. From the main menu bar, select ToolsReference Point and choose the

center of the arc to create a reference point for the part.

Materials and sectionThe steel plate is assumed to be elastic-plastic. Although rate-dependent plastic behavioris usually considered in rolling simulations, it is not considered here.

W15.2

Page 3: Workshop15 rolling-plate

1. Switch to the Property module. 10. From the main menu bar, select MaterialCreate. Create a material named

Steel with the following properties: · Modulus of elasticity: 1.5E11 Pa· Poisson's ratio: 0.3· Density: 7850 kg/m3

· The initial yield stress is 168.72 MPa rising to 448.45 MPa at 100% strain.The plasticity data are summarized in Table W15–1:

Yield stress (Pa) Plastic strain1.6872 E8 0.02.1933 E8 0.12.7202 E8 0.23.0853 E8 0.33.3737 E8 0.43.6158 E8 0.53.8265 E8 0.64.0142 E8 0.74.1842 E8 0.84.3401 E8 0.94.4845 E8 1.0

Table W15–1. Yield stress-plastic strain data

11. From the main menu bar, select SectionCreate and create a homogeneoussolid section named plateSection with a default thickness of 1.0.

12. From the main menu bar, select AssignSection and assign the section to thepart named plate.

AssemblyYou must now instance the parts and position the plate relative to the roller.

1. Switch to the Assembly module.13. From the main menu bar, select InstanceCreate, select both parts, and click

OK.To position the plate relative to the roller, it is necessary to identify the location on theroller where contact will first occur between the parts. Then datum geometry can be usedto facilitate the positioning. In this problem the top-right corner of the plate will first makecontact with the roller at a point that is located approximately 20% of the distance alongthe edge of the roller (relative to the bottom vertex of the roller).

14. From the main menu bar, select ToolsDatumPoint. Choose the Useparameter method, select the roller edge, and specify a normalized edgeparameter of 0.2.

W15.3

Page 4: Workshop15 rolling-plate

15. From the main menu bar, select InstanceTranslate to modify the positionof the plate. Select the starting and end points shown in Figure W15–3 todefine the translation vector.

Figure W15–3. Part positioning

Sets and surfacesTo facilitate the application of loads, contact, etc., you will create geometry sets andsurfaces.

1. From the main menu bar, select ToolsSetCreate and create the followingsets corresponding to the regions shown in Figure W15–4:

left: The left edge of the platebottom: The bottom edge of the plateplate: The entire platerefPt: The reference point of the roller

W15.4

end point start point

refPt

Page 5: Workshop15 rolling-plate

Figure W15–4. Geometry sets

16. From the main menu bar, select ToolsSurfaceCreate and create thefollowing surfaces corresponding to the regions shown in Figure W15–5:

roller: Side of the roller facing the platetopPlate: Top and right edges of the plate

Figure W15–5. Surfaces

Analysis step and output requestsThe rolling simulation will be performed using a single explicit dynamics analysis step.

1. Switch to the Step module.17. From the main menu bar, select StepCreate to create a Dynamic, Explicit

step named Single Pass Rolling with a time period of 0.1 seconds. Acceptall defaults for the time incrementation and other parameters.

Because rate effects are usually considered in rolling problems, the only method availableto speed up the simulation effectively is mass scaling.

18. Open the Mass Scaling tabbed page of the Edit Step dialog box. In this page,select Use scaling definitions below then click Create. Choose theApplication Region as Set; and from the pull down menu, select plate.Enter a scale by factor value of 1600, and click OK.

19. Accept the default field output requests. From the main menu bar, selectOutputHistory Output RequestsCreate and request stored historyoutput to the output database at 100 equally spaced time intervals during theanalysis for reaction moment RM3 at the roller reference point. Use the setnamed refPoint.

W15.5

left bottom plate

topPlateroller

Page 6: Workshop15 rolling-plate

Very large deformations are anticipated in this analysis. Use the adaptive meshingcapability available in ABAQUS/Explicit to reduce the amount of mesh distortion andmaintain a high quality mesh throughout the analysis.

20. From the main menu bar, select OtherAdaptive Mesh DomainManager. a. In the Adaptive Mesh Domain Manager, click Edit.a. In the Edit Adaptive Mesh Domain dialog box, toggle on Use the

adaptive mesh domain below. Select plate as the region. Specify afrequency of 10 and 3 mesh sweeps per increment.

b. Toggle on Adaptive mesh controls, and click Create in the right side ofthe dialog box. Define adaptive mesh controls using all supplied defaultparameters.

ContactSurface-to-surface contact will be defined between the top surface of the plate and theouter surface of the roller. Coulomb friction with a coefficient of 0.4 will be used.

1. Switch to the Interaction module. 21. From the main menu bar, select InteractionPropertyCreateContact

and click Continue. 22. Select MechanicalTangential Behavior, and choose the Penalty friction

formulation. 23. Enter a friction coefficient of 0.4. Click OK. 24. From the main menu bar, select InteractionCreate. 25. In the Create Interaction dialog box, select Single Pass Rolling as the step

and select Surface-to-surface contact (Explicit) as the interaction type. ClickContinue. When prompted for the surfaces involved in the contact interaction,click Surfaces in the prompt area to open the Region Selection dialog box.Select roller as the master surface and topPlate as the slave surface.

Boundary conditionsThe roller spins about the global Z-axis with an angular velocity of 6.2832 radians/sec.The plate will be given an initial velocity of 1.01587m/sec in the global X-direction, whichis equal to the X-direction velocity component of the roller at the point where contact firstoccurs. This minimizes the initial transient disturbance since the initial acceleration in theX-direction at the contact point is zero.

1. Switch to the Load module.26. From the main menu bar, select BCManager to open the Boundary

Condition Manager. Create the boundary conditions listed in Table W15–2:a. Click Create in the Boundary Condition Manager.c. In the Create Boundary Condition dialog box, select

Displacement/Rotation as the type and click Continue.

BC name Step Region Boundary condition

W15.6

Page 7: Workshop15 rolling-plate

bottom Initial bottom U2=0fixRoll Initial refPt U1=U2=0

rotateRoll Single pass rolling refPt VR3=6.2832

Table W15–2. Boundary conditions

Initial conditionsAs mentioned earlier, the plate is given an initial velocity of 1.01587 m/sec in the globalX-direction.

1. From the main menu bar, select FieldCreate. 27. In the Create Field dialog box, name the field initVel, set the step to

Initial, accept the default category, and click Continue. 28. In the prompt area, click Sets, select plate, and click Continue. 29. In the Edit Field box, enter a value of 1.01587 m/sec for the velocity

component V1.

MeshThe plate will be meshed with 150 plane strain CPE4R elements.

1. Switch to the Mesh module.30. From the main menu bar, select MeshElement Type and select the plate by

clicking on it. Examine the various options available in the Element typedialog box, change the element library to Explicit and the element family toPlane Strain, and accept the default element type CPE4R.

31. From the main menu bar, select SeedInstance, select the plate, and specifya seed size of 0.002.

32. From the main menu bar, select MeshInstance. Select the plate as theinstance to be meshed, and click Done in the prompt area. The mesh is shownin Figure W15–6.

Figure W15–6. Plate mesh

W15.7

Page 8: Workshop15 rolling-plate

Analysis1. Switch to the Job Module. 33. Select JobCreate, create a job named roll-xpl, and click Continue.

Accept the default job parameters, and click OK.34. From the main menu bar, select FileSave As and save the model database as

roll.cae.35. From the main menu bar, select JobManager to open the Job Manager.

Click Submit to submit the job for analysis.36. Monitor the progress of the job by clicking Monitor in the Job Manager.

Visualization1. Once the analysis completes successfully, click Results in the Job Manager. 37. Plot the undeformed and the deformed model shapes. 38. From the main menu bar, select ViewODB Display Options and under the

Sweep and Extrude tab, set the Depth to 0.01. Turn on shaded render style,and rotate the model.

39. Plot the contours for MISES stress and plastic strain PEEQ. The contours forMises stress are show in Figure W15–7.

Figure W15–7. Mises stress contours

40. From the main menu bar, select AnimateTime History to animate thehistory of the Mises stress distribution and the resulting deformation.

41. From the main menu bar, select ResultHistory output to create X–Y plotsfor the model kinetic energy (ALLKE), external work (ALLWK), internalenergy (ALLIE), and total energy (ETOTAL). In the History Output dialogbox, click Plot to display the curves and click Dismiss to close the box. Theplot is shown in Figure W15–8.

W15.8

Page 9: Workshop15 rolling-plate

Figure W15–8. Model energies

42. Plot the history of the reaction moment RM3, and save the curve as RM3 XPL.

Implicit analysis modelNow perform the simulation using ABAQUS/Standard. From the main menu bar, selectModelCopy, and copy the model named explicit to a new model namedstandard. Make the following changes to this model:

1. Switch to the Step module, and delete the step named Single Pass Rolling.Note that this deletes all previously defined step-dependent objects such asloads, contact interactions, etc.

For the implicit analysis, the static analysis procedure will be used. Note, however, thatthe simple analysis technique used earlier (whereby the initial plate velocity wasprescribed and a single analysis step was used) will not yield the desired results inABAQUS/Standard. The reason is that, in a static step material, inertia is neglected. Thus,two steps are needed to perform the simulation. In the first step firm contact must beestablished between the plate and the roller. This then allows the roller to draw the plate inthe second step, where the roll pass event will be simulated.

43. Create a Static, General step named Establish Contact with thefollowing parameters:· Total time period = 0.001 sec· Maximum number of increments = 100 · Initial time increment size = 0.0001 sec· Minimum increment size = 1E-8 sec· Maximum increment size = 0.001 sec· NLGEOM toggled on

W15.9

Page 10: Workshop15 rolling-plate

44. Create a second Static, General named Roll Pass with the followingparameters:· Total time period = 0.099 sec· Maximum number of increments = 500· Initial time increment size = 0.0001 sec· Minimum increment size = 9.9E-7 sec· Maximum increment size = 0.099 sec

45. Create a history output request for reaction moment RM3 for the set refPt.46. From the main menu bar, select OutputRestart Requests and specify a

restart frequency of 250 for each step. For problems dominated by highly discontinuous nonlinearities (such as contact andfriction), nondefault analysis controls may aid the convergence behavior. In this problemallow extra equilibrium iterations for the resolution of these discontinuities, as describedbelow.

47. From the main menu bar, select OtherSolution ControlsEdit RollPass to edit the solution controls for this step.

48. In the solution controls editor, select Specify. In the Time Incrementationtabbed page of this dialog box, select Discontinuous analysis. Click OK toclose the dialog box.

49. Switch to the Interaction module. a. From the main menu bar, select InteractionCreate. d. In the Create Interaction dialog box, select the step Establish Contact,

accept the default Surface-to-surface contact (Standard) type, and clickContinue.

e. In the prompt area, click Surfaces; use roller as the master surface, andtopPlate as the slave surface.

50. Switch to the Load module. a. From the main menu bar, select BCCreate. f. In the Create Boundary Condition dialog box, select Velocity/Angular

velocity as the type and click Continue. g. Create the following velocity conditions for the sets as shown in

Table W15–3.

BC name Step Region Boundary conditionfeed piece Establish Contact left V1=1.01587

roller Establish Contact refPt VR3=6.2832

Table W15–3. Boundary conditions

h. From the main menu bar, select BCManager, select the feed pieceboundary condition in the Roll Pass step, and Deactivate it.

51. Switch to the Mesh module.

W15.10

Page 11: Workshop15 rolling-plate

a. From the main menu bar, select MeshElement Type. i. Select the plate; and, in the Element type dialog box, change the element

library to Standard and click OK.52. Switch to the Job module.

a. Select JobCreate, and create a job named roll-std.b. Save the model database.j. Open the Job Manager, and submit the job roll-std for analysis.k. Monitor the progress of the job by clicking Monitor in the Job Manager.

W15.11

Page 12: Workshop15 rolling-plate

Visualization1. Once the analysis completes successfully, click Results in the Job Manager. 53. Plot the undeformed and the deformed model shapes. 54. Plot the contours for MISES stress and plastic strain PEEQ. 55. Resize the viewport by clicking on its lower right corner and dragging it so that

it covers the top half of the canvas area. Create a second viewport by selectingCanvasCreate Viewport from the main menu bar, and draw a rectangle bydragging the mouse across the lower half of the canvas area.

56. Switch to the output database file roll-xpl.odb, and plot the contours forPEEQ. The contours for PEEQ for both analyses are shown in Figure W15–9.

Figure W15–9. PEEQ for the implicit and explicit solutions

57. Save the time history for the reaction moment RM3 as RM3 STD. Plot bothcurves as shown in Figure W15–10.

W15.12

implicit solution

explicit solution

Page 13: Workshop15 rolling-plate

Figure W15–10. Comparison of the reaction moment history

W15.13