Remeshing Method in Dynamic Mesh


I'm about to simulate a rotary compressor part with air in between. Below you will see the picture of the part that is being compressed with air. I am using the dynamic mesh with remeshing to simulate the compressing process of this part.

Zones of object

The zones are defined in Dynamic Mesh as:

  • Wall-top and Wall-bot as Deforming with geometry definition of cylinder
  • Wall-back and Wall-front as Deforming with geometry definition of plane
  • Wall-left, Wall-bot-left, Wall-right and Wall-bot-right as Rigid Body with UDF Define_CG_Motion (a sinusodial function)

I used time step size of 0.01s with 100 number of time steps but the simulation stops at 0.35s as a problem with 'negative cell volume detected' occurs. I would like to simulate the process till the ends where the bottom part becomes almost a sharp edge. Below shows the end results of the simulation.

End of Preview Mesh Motion

Following are my questions:

  • Is there a way that I can make the wall-bot-left and wall-bot-right to also deform and acts as a rigid body?
  • Can I make the wall-bot to be deleted when a certain minimum value achieved?
  • Is there an alternative way to solve the problem faced?

Thank you in advance for you help.



  • Ray5049Ray5049 Member
    edited January 23

    The part should be compressed from 33degree to 9 degree.

  • RobRob UKForum Coordinator
    edited January 23

    You can't change topology in a model so you may need to rethink the approach. You can make any/all faces deform, you just need to set them up to do that. 

  • Ray5049Ray5049 Member
    edited January 27

    Thank you for your reply.

    So another question from me is, is it possible that at this point I want to make the part to go back to its original shape after reaching the maximum deforming of the bottom part as shown in the picture? Is it possible to write this condition in udf?

  • RobRob UKForum Coordinator
    edited January 27

    You can write position data into UDM, but if you remesh I'm not sure how well that will work. 

    If it's a cyclic motion you can easily return to the starting shape, otherwise you'll probably have to reload the model. You may be able to reload the mesh to avoid needing to set up again if you didn't save the case before checking the motion. 

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