Contact Analysis Tutorial _Block With Pin_20.09.14

8/10/2019 Contact Analysis Tutorial _Block With Pin_20.09.14

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9/19/2014 Print F-F Contact

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Interference Fit and Pin Pull-Out Contact Analysis

Problem Specification

Problem Description

Build Geometry Steps

Define Material Property and Element Type Steps

Generate Mesh Steps

Specify Solution Criteria Steps

Load Step 1 Steps

Load Step 2 Steps

Postprocessing Steps

Problem Specification

Applicable ANSYS Products: ANSYS/Multiphysics, ANSYS/Mecha nical , ANSYS/Structural, ANSYS/ED

Level of Difficulty: moderateInteractive Time Required: 75 to 100 minutes (includes 45 to 50 minutes for solution)

Discipline: structural

Analysis Type: nonlinear quasi-static

Element Types Used: SOLID92, TARGE170, CONTA174

ANSYS Features Demonstrated: solid modeling, Boolean operations, symmetry boundary conditions, coupling, flexible-to-flex ible surface contact, contact wizard,

automatic time stepping, multiple load steps, symmetry expansion, animation, time history postprocessing

Problem Description

This is a 3-D analysis of a s teel pin contacting a smooth pinhole in a block. Because of the inherent symmetry of the model, the analysis is performed on a quarter symmetry model. Two

different load steps are defined. The objective of the first load step is to observe the interference fit stresses of the pin which is geometrically thicker than its pinhole. The objective of the

second load step is to observe the stresses, contact pressures and reaction forces due to the motion of the pin being pulled out from the block.

Given

The dimensions of the model are as follows: PIN radius = 0.5 units, length = 2.5 units. BLOCK width = 4 units, length = 4 units, depth = 1 unit. P INHOLE radius = 0.49 units, depth = 1 uni

Both solids are made of structural s teel (stiffness = 30e6) and are assumed to be flexible.

Approach and Assumptions

A quarter symmetry model is appropriate to simulate the contact phenomena. Two load steps are used to set up the analysis :

Load Step 1: Interference Fit -- solve the problem with no additional displacement constraints. The pin is constrained within the the pinhole due

to its geometry. S tresses are generated due to the general misfit between the target (pinhole) and the contact (pin) surfaces.

Load Step 2: Pull-out -- move the pin by 1.7 units out of the block using DOF displacement conditions on coupled nodes. Explic itly

invoke Automatic Time Stepping to guarantee solution convergence. Read results for every 10th substep during solution.

Summary of Steps

Use the information in the problem description and the steps below as a guideline in solving the problem on your own. Or, use the detailed interact ive step-by-step solut ion by choosing the

link for step 1.

NOTE: To run this tutorial, a total workspace memory of at least 64MB is required, preferably higher (100-200 MB). Before starting the tutorial, check your workspace memory as follows:

1. Utility Menu: List

Status

Configuration

2. Scroll down to the MEMORY STATISTICS heading and read the number of MB for Requested Work Space

If this number is acceptable, proceed with the tutorial. If the number is t oo low, quit ANSYS without saving changes, re-start ANSYS and, in the ANSYS 5.5 Interactive dialog box, enter th

appropriate number in the Memory requested for Total Workspace field before choosing Run.

Build Geometry

1. Create block.

2. Create target surface.

3. Create pin.

4. Create quarter symmetry model.

Define Material Property and Element Type

5. Define material.

6. Define element type for solid volume.

Generate Mesh

7. Mesh solid volume.

8. Smooth element edges for graphics display.

9. Create contact pair using Contact Wizard.

Specify Solution Criteria

10. Apply symmetry constraints on (quartered) volume.

11. Define boundary constraints on block.

12. Turn on large deformation effects.

13. Define coupled nodes.

Load Step 1

14. Define interference fit analysis options.

15. Solve load step 1.


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http://www.ansys.stuba.sk/html/tutor_55/print_ffcontact.htm 2

Load Step 2

16. Set DOF displacement for pin on master node.

17. Define pull-out ana lysis options.

18. Write results to file.


Postprocessing

20. Expand model from quarter symmetry to full volume.

21. Observe interference fit stress state.

22. Observe intermediate contact pressure on pin.

23. Observe pulled-out stress state.

24. Animate pin pull-out.

25. Plot reaction forces for pin pull-out.

26. Exit the ANSYS program.

Build Geometry

1. Create block.

Create rectangular solid block by specifying XYZ

coordinates.

1. Main Menu: Preprocessor

-Modeling-Create

-Volumes-Block

By Dimensions

2. Enter X1 = -2, X2 = 2, Y1 = -2, Y2 = 2, Z1 =

2.5, Z2 = 3.5 -

3. OK -

4. Utility Menu: Plot Ctrls

Pan, Zoom, Rotate

5. Click on ISO button -

6. Close -

2. Create target surface (hole in block).

Create cy linder by specifying the radius and depth.


-Modeling-Create

-Volumes-Cylinder By Dimensions

2. Enter RAD1=0.49, Z1=2.5, Z2=4.5 -

3. OK -

Subtract cylinder from block.


-Modeling-Operate

-Booleans-Subtract

Volumes

5. Pick the block, Volume 1 as base

volume from which to subtract

6. OK (in picking menu)

7. Pick the cylinder Volume 2 (created in

the first part of this step above) as the

volume to be subtracted


9. Utility Menu: Plot

Replot


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3. Crea te pin.

Create cy linder by specifying the radius and depth.


-Modeling-Create

-Volumes-Cylinder By Dimensions

2. Enter RAD1=0.5, Z1=2, Z2=4.5 -

3. OK -

4. Utility Menu: Plot Controls

Numbering

5. Turn on Volume numbering -

6. OK -


Replot

4. Create quarter symmetry model.

1. Utility Menu: WorkPlane

Display Working Plane (toggle on)


WP Settings

3. Choose Grid and Triad -

4. OK -

Rotate Working Plane by 90

o

in Y direction anddivide volumes into two halves.


Offset WP by Increments

6. Slide bar to 90ofor Rotation Angle -

7. Click once on Rotate +Y direction -

8. OK -


-Modeling-Operate

-Booleans-Divide

Volu by WrkPlane

10. Pick All (in picking menu)


Replot

12. Toolbar: SAVE_DB

Rotate Working Plane by 90oin X direction and

divide volumes into four quarters.


Offset WP by Increments

14. Click once on Rotate +X direction -

15. OK -


-Modeling-Operate

-Booleans-Divide

Volu by WrkPlane




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Display Working Plane (toggle off)


Replot


Delete volumes to create quarter symmetry model.

21. Main Menu: Preprocessor -Modeling-Delete

Volume and Below

22. Pick volumes on 3/4 of the model

Volume numbers 1, 3, 8 for the pin; and

10, 11, 12 for the block



Replot


Define Material Propertyand Element Type.

5. Define material.


Material Props

-Constant-Isotropic

2. OK to define materia l 1 -

3. Enter 36e6 for EX (Young's modulus) -

4. OK

6. Define element types.


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Element Type

Add/Edit/Delete

2. Add an element type -

3. Choose Structural Solid family of

elements -

4. Choose Tet 10 node 92 (SOLID92) -

5. OK to apply this element type -

6. Close the element type dialog box -

Generate Mesh

7. Mesh solid volume.


Mesh Tool

2. Turn on SmartSizing -

3. Move slider to level 8 -

4. Choose Volume meshing -

5. Click on Tet -

6. Click on Free -

7. Click on Mesh -

8. Pick volume 7 (cylinder)



Volumes

11. Click on Mesh -

12. Pick volume 9 (block)


14. Close the Mesh Tool

8. Smooth element edges for graphics display.


Style

Size & Shape

2. Choose 2 facets/edge -3. OK -


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9. Create contact pair using Contact Wizard.


-Modeling-Create

Contact Pair

Contact Wiza rd

2. Choose Areas -

3. Choose Flexible -

4. Choose Pick Target -

5. Pick Area 24 (surface of pin hole in

block) as the target


7. Choose Next -

8. Choose Areas -

9. Choose Pick Contact -

10. Pick Area 20 (surface area of pin) as the

contact


12. Choose Next -

13. Enter 1 for Material ID -

14. Enter 0.2 for Coefficient of Friction -

15. Choose Initial Penetration -

16. Choose Create -

17. Choose Finish -


-Modeling-Create

Contact Pair

View Pair

19. Choose Contact pair -

20. Choose normals shown -

21. Choose Display -

22. Make other viewing choices as desired

with each followed by Display

23. Choose Close when you are done -


Areas


Specify Solution Criteria

10. Apply symmetry constraints on (quartered)

volume.

1. Main Menu: Solution

-Loads-Apply

-Structural-Displacement

-Symmetry B.C.-On Areas

2. Pick interior area s that were exposed

when original model was quartered --

Area numbers 4, 14, 26, 39.


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11. Define boundary constraints on block.


-Loads-Apply


On Areas

2. Pick left side of block -- Area number 38

3. OK (in the picking menu)

4. Choose All DOF for DOFs to be

constrained -

5. Enter 0 for Displacement value -

6. OK to apply the constraints -

12. Turn on large deformation effects.

1. Main Menu: Solution -Analysis Type-Analysis Options

2. Turn on Large deformation effects -

3. OK to apply the options -

13. Define coupled nodes.


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Coupled nodes are defined in order to apply DOF

constraints to one node, called a "master" node,

which is coupled to all the nodes on the front

surface area of the pin. All coupled nodes are

forced to assume the same displacement value in

the specified UZ nodal coordinate direction. In the

first load step to investigate the results of an

interference fit problem, the displacement is zero.

In the second load step the master node (and all

coupled nodes associated with it) is given a

displacement value of 1.7 to observe the effects of

pulling the pin out of the block.

1. Utility Menu: Se lect

Entities

2. Choose Areas -

3. Choose By Num/Pick -

4. Select From Full -

5. Apply

6. Pick front surface of pin head (z=4.5) --

Area number 13


8. Choose Nodes -

9. Choose Attached to -

10. Choose Areas, all -11. Choose From Full -

12. OK -


Nodes


Coupling/Ceqn

Couple DOFs


16. Enter 1 for Reference number -

17. Choose UZ for Degree-of-freedom label

-18. OK -

Note: observe which node is the master node (the

one that all arrows are directed towards). The

master node number will vary depending on the

mesh.

19. Utility Menu: Select

Everything


Areas

Load Step 1

14. Define interference fit ana lysis options.


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-Load Step Opts-Time/Frequenc

Time and Substps

2. Enter 100 for Time at end of load step

-

3. Enter 1 for Number of substeps -

4. Choose Ramped B.C. -

5. Turn off Automatic time stepping -

6. OK -

7. Toolbar: SAVE_DB



-Solve-Current LS

2. Review the information in the status

window, then choose File

Close (Windows NT/Windows 95), or

Close (X11/Motif), to close the window

-

3. OK to begin the solution -

4. Close the information window when

solution is done -

5. Utility Menu: Plot Replot

Load Step 2

16. Set DOF displacement for pin on master

node.


-Loads-Apply


On Nodes

2. Pick master node (lower right corner of

the pin)


4. Choose UZ for All DOFs to be

constrained -

5. Enter 1.7 for displacement value -

6. OK -

17. Define pull-out analysis options.


-Load Step Opts-Time/Frequenc

Time and Substps

2. Enter 200 for Time at end of load step -

3. Enter 100 for Number of substeps -

4. Choose Ramped B.C. -

5. Turn Automatic time stepping On -

6. Enter 10000 for maximum number of

substeps -

7. Enter 10 for minimum number of

substeps -

8. OK -


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18. Write results to file.


-Load Step Opts-Output Ctrls

DB/Results File

2. Choose Every nth substep for File write

frequency -

3. Choose -10 for N -

4. OK -

5. Toolbar: SAVE_DB



-Solve-Current LS

2. Review the information in the status

window, then choose File

Close (Windows NT/Windows 95), or

Close (X11/Motif), to close the window

-

3. OK to begin the solution -

4. Close the information window when

solution is done -

Note that this solution takes approximately 30

minutes.

Postprocessing

20. Expand model from quarter symmetry to

full volume.

1. Utility Menu: PlotCtrls

Style

Symmetry Expansion

Periodic/Cyclic Symmetry

2. Select 1/4 Dihedral Sym -

3. OK -


Elements

5. Toolbar: SAVE_DB

21. Observe interference fit stress state.

1. Main Menu: General Postproc

-Read Results-By Load Step

2. Enter 1 for Load step number -

3. OK -


Plot Results

-Contour Plot-Nodal Solution

5. Choose Stress as item to be contoured


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-

6. Scroll down and choose von Mises

(SEQV) -

7. OK -

22. Observe intermediate contact pressure on

pin.


-Read Results-By Time/Freq

2. Enter 120 for value of time/freq -

3. OK -


Entities

5. Choose Elements -

6. Choose By Elem Name -

7. Enter 174 for Element name -

8. OK -

9. Utility Menu: Plot Elements


Plot Results

-Contour Plot-Nodal Solu

11. Choose contact -

12. Choose pressure -

13. OK -

23. Observe pulled-out stress state.


Everything


-Read Results-By Load Step

3. Enter 2 for Load step number -

4. OK -


Plot Results -Contour Plot-Nodal Solution

6. Choose Stress as item to be contoured

-


(SEQV) -

8. OK -

24. Animate pin pull-out.


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Animate

Over Results

2. Choose Load Step Range for Modal

result data -

3. Include last substep for each load step

-

4. Turn Auto contour scaling on -

5. Choose Stress as Contour data for

animation -


(SEQV) -

7. OK -

For Windows NT/Windows 95 systems only: the

Media Player appears. Make sure the AutoRepeat option is selected before viewing the

animation.

For UNIX systems only: make choices in the

ANSYS Animation Controller before viewing the

animation.

25. Plot reaction forces for pin pull-out.


Volumes

2. Main Menu: Time History Postpro

Define Variables

3. Add a variable -

4. Choose Reaction forces for Type of

variable -

5. OK -

6. Pick master node


8. Enter 2 for Reference no. of variable -

9. Enter node number -

10. Enter FZ for data item -

11. OK -

12. Close -

13. Main Menu: Time History Postpro

Graph Vars

14. Enter 2 for First variable to graph -

15. OK -

26. Exit the ANSYS program.

1. Toolbar: Quit

2. Choose Quit - No Save! -

3. OK -

Congratulations! You have completed this

tutorial.


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Documents

Contact Analysis Tutorial _Block With Pin_20.09.14