shared topology for so many contact surfaces

- June 2, 2020 at 6:44 pm
  
  ehsan120
  Subscriber
  
  Hi,
  
  I have a model that in different regions we have different materials. So, I have so many components made by patterns and other features, and corresponding materials are assigned to them. Since all of them are in contact with the neighbor surfaces (more than 2000 contact surfaces), and I don't have any relative displacement between contact surfaces, I usually have two choices: the bonded contact or the shared topology. As far as I know, the shared topology technique is the best choice to merge nodes between two shared regions and improve the mesh quality. However, whenever I want to use shared topology, it cannot find all the surfaces in contact and as a result, we still have bonded contacts automatically detected by Ansys. Do you have any solution for it? I also opened the geometry in DM and try to make a new part there but it takes forever to open the model in the mechanical. Even if I wait for a long time for mechanical to open the file, it give a funny model that has many extra lines and volumes.
  
  Oh, by the way, it seems that if we have patterned layers that are not in contact, we have no choice but to make them independent of each other, and then shared topology will find shared surfaces of these pattern instances with the surrounding. am I right?
  
  Last question: is there any way in Ansys to mesh part (component) by part?
  
  Thanks in advance for the response
- June 2, 2020 at 11:53 pm
  
  Karthik Remella
  Administrator
  
  Hello,
  
  There might be some issue with the geometry. Could you please open your geometry in SCDM and run the 'Check Geometry' option? Please select the main component, right-click, and perform the 'Check Geometry' operation in SCDM?
  
  Please let us know what you find?
  
  Thanks.
  
  Karthik
- June 3, 2020 at 12:33 am
  
  ehsan120
  Subscriber
  
  Thanks for the response. As you suggested, I have used the "check geometry" option in the SpaceClaim on the main component. It says "no geometry problems found".
  
  One question, if I couldn't find a way to solve this issue with the shared topology, can I stay with bond contact for now? Are these contact surfaces making any divergence problems?
  
  Thanks
- June 3, 2020 at 1:15 am
  
  peteroznewman
  Subscriber
  
  There is a third option that is not shared topology and not bonded contact.
  
  That is Mesh Merge. If a global element size causes all the coincident edges to have an equal number of nodes, that will create coincident nodes. Mesh Merge is very robust at eliminating coincident nodes, and in doing so, connecting elements at geometry boundaries.
- June 3, 2020 at 4:32 pm
  
  ehsan120
  Subscriber
  
  Thanks for the response. Honestly, the geometry is not that easy to define node merge easily. What I did usually for large models was to open it in DM and use "form a new part". However, this time, I don't know why, after doing so and opening the model in the mechanical (I have to wait for more than 1-2 hours for WB to transfer the data to the mechanical), some parts are disappeared and some extra lines are imported inside it. I am using Ansys 2020 R1. I have no idea whether I will get a proper result if I draw the CAD from scratch in design modeler or not.