Contact Simulation involving Soft Tissue

- December 30, 2019 at 9:41 am
  
  SAM3185
  Subscriber
  
  Hi Everybody,
  
  I'm simulating a hard-to-converge contact between a device and soft tissue. Now as part of my study I should develop some user-defined contact subroutines in ANSYS. I have no clue how I should proceed as I couldn't find a useful example. Is there any person who has experienced using user defined contact specifications in ANSYS? I'm in a dire need of help. So please share your experiences with me.
  
  Thanks in advance
- December 30, 2019 at 6:31 pm
  
  peteroznewman
  Subscriber
  
  Contact can be hard to obtain convergence, but there are many paths to success. I have never taken the user-defined contact subroutine path, I doubt that is necessary.
  
  Can you share your model? If so, do File > Archive... and save a .wbpz file. If the file is < 120 MB, then you can use the Attach button that appears after you post a reply. Put the version of ANSYS you are using in your reply.
  
  If the file size is > 120 MB, clear the mesh, and make a new archive.
- February 3, 2020 at 11:14 am
  
  SAM3185
  Subscriber
  
  Hi peteroznewman
  
  Thanks for your reply and sorry for my late follow-up.
  
  Actually apart from convergence issues I faced during my many many simulations, I should study these user contacts anyway. So I appreciate any further help in this regard.
  
  Is it possible to share the model with you directly, like sending to your email or another way?
  
  thanks in advance.
- February 3, 2020 at 2:09 pm
  
  peteroznewman
  Subscriber
  
  Hi Sam,
  
  I only use this site to share models. I understand a model may be proprietary. Others in that situation have made surrogate models that display the same problem, but contain no proprietary geometry, then they can share on this public website.
  
  Or if you just want to limit the exposure it has, you can post a reply with the attachment or link when you see I am online, and I can delete the attachment or link after I download it.
  
  Regards,
  Peter
- February 3, 2020 at 2:46 pm
  
  SAM3185
  Subscriber
  
  Thanks for your response Peter,
  
  To be honest, I didn't understand the surrogate idea. My problem is geometry dependent and If I change the geometry of the model the convergence issues would be changed as well.
  
  but for the second way can I send it now and delete very quickly right after?
- February 3, 2020 at 3:41 pm
  
  peteroznewman
  Subscriber
  
  The recommended way is to have the file open in Workbench and use File, Archive and create a .wbpz file that you can Attach.
- February 3, 2020 at 4:07 pm
  
  peteroznewman
  Subscriber
  
  The website allows .zip files to be attached.
- February 3, 2020 at 4:09 pm
  
  peteroznewman
  Subscriber
  
  I'm a bit of a novice in the Mechanical APDL interface. I'm good at Workbench/Mechanical. I think I can import the model into Workbench using External Model.
- February 3, 2020 at 4:15 pm
  
  SAM3185
  Subscriber
  
  Ok. I attached the cdb and iges of the model which is a 2D Axisymmetric version of a 3D model.
- February 3, 2020 at 4:49 pm
  
  SAM3185
  Subscriber
  
  Did you download the files?
- February 3, 2020 at 6:24 pm
  
  peteroznewman
  Subscriber
  
  I have the cbd and iges files now.
  
  You can delete the attachment.
- February 3, 2020 at 7:42 pm
  
  SAM3185
  Subscriber
  
  I normally use ANSYS 18.0.
  
  Yes you are right. I have tried for other finer and probably better meshes. But sometimes having larger mesh sizes helps reduce error in element formulation due to distortion of element. If you could manage to delete pics it is better. Did you try with this improved mesh sizes?
  
  thanks a lot
- February 3, 2020 at 8:47 pm
  
  peteroznewman
  Subscriber
  
  Loads and boundary conditions didn't import into the External Model so I don't know what they were and so it is not ready to solve.
  
  Maybe I could see that in APDL, but I don't know how to navigate there.