×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Ansys Workbench Contact-problem

Ansys Workbench Contact-problem

Ansys Workbench Contact-problem

(OP)
I have a problem that requires me to do a simple simulation of a sheet metal stamping. I have access to Ansys Workbench v12 Academic version, and have familiarized myself with the program and tried to read up on its features and limitations.

The simulation is selected as a static structural.

The boundary conditions are set as:
* The lower die-tool underside is set with a Fixed Support
* The upper die-tool vertical sides are set with Frictionless support, to allow a movement in the vertical direction.
* The sheet metal plate´s long sides are also set with Frictionless support, to prevent a possible Rigid-body motion, but still allow a vertical press movement.
* The upper tool is applied with a displacement towards the second tool.
* There is a initial contact between the platesurfaces and the tool's pressure surfaces.
* There a two sets of contacts. First, the upper tool´s whole stamping-area and the surface of the plate that it intersects with. Second, the lower tool´s surface and the bottom surface of the plate.

My problem occurs when I am applying the contact conditions for the contact area. Ansys choice is initially a bonded contact, and simulations can be done. However, this does not simulate the reality as we do not allow room to stretch and slide the plate. I would therefore choose a Frictional contact and puts friction to about 0.3, just to test out. Then the simulation would not converge, and the upper tool glides right through the plate without being aware of when a contact occurs.
Could it be that Workbench is not allocated for this type of simulation, or do I choose the wrong settings?
Would any kind person be able to explain if this is not possible, and if so, what restrictions of the program that causes this?

Best regards, J-H

RE: Ansys Workbench Contact-problem

You'll need to initialise the contact in the model. You can try either telling ANSYS that you have initial contact between the parts and solve (check the gap between the parts and set the initial contact tolerance based on this value), or you can create a multi-step analysis. The first step in the multi-step case will be a small displacement applied to the part to establish initial contact, and then a second step to apply the full load on the model.


------------
See FAQ569-1083: Asking questions the smart way on Eng-Tips fora for details on how to make best use of Eng-Tips.com

RE: Ansys Workbench Contact-problem

Ansys is capable of this type of problem.  However there are a few issues that the user has to verify/check to get convergence.
- contact stiffness
- mesh size
- time step/load increments.

Ask yourself, is this problem non-linear?  Will the material encounter plastic deformation?  If so you will have to input a material curve and use a non-linear material model.  

If you are not using the correct physics for the problem your results will be meaningless.

Can you take advantage of symmetry?  At first glance it looks like you could have two planes of symmetry and thus reduce the size of your problem.

What are trying to get out of this analysis?   

____________
JohnyGluebag

RE: Ansys Workbench Contact-problem

You can also try manually setting the pinball radius in the contact settings within Ansys WB.  I have had instances in the past where the "Automatic" setting did not work and required me to manually enter the pinball radius.

Good luck,

Steve
 

Stephen Seymour, PE
Seymour Engineering & Consulting Group
www.seymourecg.com  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources