mechanical nonlin 13.0 ws 03a contact stiffness

8/12/2019 Mechanical Nonlin 13.0 WS 03A Contact Stiffness

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Customer Training Material

or s op

Contact Stiffness Stud

Structural Nonlinearities

WS3A-1ANSYS, Inc. Proprietary

2010 ANSYS, Inc. All rights reserved.Release 13.0

December 2010


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ANSYS Mechanical Structural Nonlinearities

Customer Training MaterialWorkshop 3A Contact Stiffness Study

Goal:

Perform a convergence study on contact stiffness



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Customer Training Material Workshop 3A: Contact Stiffness Study

Steps to Follow:

Restore Archive browse for file W3a-stiffness.wbpz

Save as

File name: W3a-stiffness

*



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Customer Training Material Workshop 3A Contact Stiffness Study

Return to Project Schematic

Utility Menu > Return to Project

Double click on the Model ell to open the FE Model Mechanical ession

(or RMB=>Edit)



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Geometry is 2D Axisymmetric. Lower plate is rigidly constrained. Upper

plate is a flexible body with a crowned contour along bottom face. The upper

plate is under a 5MPa pressure load acting downward.

.



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A single contact pair has already been set up with the following

specifications:



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This workshop will focus on a study of the contact stiffness and its influence

on results (surface pressure and penetration).


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eri y the working unit system

Unit > Metric (mm,kg,N,s,mV,mA)

Open the folders beneath the model branch to become familiar with the

- .

Highlight Geometry and refer

to the details window to verify

that this is a 2D axisymmetric

model.

Inspect the predefined

asymmetric frictionless contact

region between the two plates.

Inspect the Analysis Settings.

Autotime stepping = ON

=



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Max substeps = 100

Large deflection = ON


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Highlight the contact region and set

Normal Stiffness to Manual and define

the Normal Stiffness Factor to 1e-002.

Execute the Solve



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Post process the Total Deformation:



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Post process the contact results:

Contact Pressure

Contact Penetration



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Record the results in Table below.

Repeat analysis with Normal Stiffness factors 0.10, 1.0, and 10.0.

For further comparison, change the contact formulation to Normal

agrange.

Contact

Formulation

Normal

Stiffness

Total

Deform

Contact

Pressure

Penetration # of iterations

actor

Aug Lagrange 0.01

Aug Lagrange 0.10

Aug Lagrange 1.0

Aug Lagrange 10.0

Norm Lagrange N/A

Experiment also with Update Stiffness between iterations and substeps

for comparison.



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c com na on o ers e es resu s n erms o accuracy an o

iterations)?


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Conclusions

Notice that as stiffness increases, contact penetration decreases while

maximum pressure increases. Notice also the general trend toward

more era ons an onger run mes. s a so wor no ng e ene

of using the automatic stiffness updating tool.

,

the overall total displacement of the assembly changes very little. This

underscores the need to know your engineering objectives.

Specifying the right contact stiffness is highly problem dependent and is

always a balance between quality of results (accuracy) and cost (run

time). Based on this study, a normal stiffness factor of 1.0 would be

satisfactory.



December 2010

mechanical nonlin 13.0 ws 03a contact stiffness

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