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General Mechanical

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How to get cavity volume in structural?

    • ansysuser
      Subscriber

      I am doing a simulation where a hollow object is compressed from external pressure.  I want to find out how much the volume inside has changed, but there appears to be no way to do this in mechanical.  In Fluent, for example, I would simply insert a plane and the look at the area of the plane to get an idea, since the object is axis symmetric.  But there is no way to insert a plane through the object in mechanical.  I thought perhaps I could insert two section planes very close to each other to look at the cross sectional area in between them and then use an image processor to get the area change, but the section planes do not work like this when showing total deformation.

      Is there any way to get the volume change of the internal cavity after compression?


       


      Thanks

    • dinhan0394
      Subscriber

      when solution done, you can export the deform geometry as 3D model. Then import to Finite Element Modeler or DesignModeler and get volume inside model

    • ansysuser
      Subscriber

      Thank you for the suggestion, but that did not work either.  I exported the deformed geometry and when I imported it into DM the cavity was still there with no way to determine the volume.  Instead I put a very thin material (density: 0.1 and Poissan's ratio: 0.01) inside, which will hopefully not change the solution much.


      If anyone else has a suggestion, please let me know.


       

    • ansysuser
      Subscriber

       That solution is still not satisfactory, as now the solution will not converge.


       


       


      Please, someone, anyone suggest a way to get the cavity volume for a deformed object!


       


      Thanks!

    • dinhan0394
      Subscriber

      when imported into DM, you can fill inside the model then determine volume of the solid inside the model.

    • ansysuser
      Subscriber

      No, that is not possible.  When I opened the geometry in DM, it had created 600+ different bodies and surfaces, like it took apart the some of the mesh and imported them as different pieces, some solid some surfaces.  I tried to do a "Unite" Boolean, but that failed.  Here is the error message on the import.


    • ansysuser
      Subscriber

      I tried merging in SpaceClaim but it says, "Cannot Merge Bodies".  Can someone please offer some advise?  This is very frustrating to do such a simple thing!


      I have attached the STL file I exported. I need the internal volume.  I thought SpaceClaim Volume tool could get it but it dies on Merge Bodies.


       


      PLEASE tell me how to get the internal volume. 


       


      Thanks!


       


       

    • jj77
      Subscriber

      I brought this in and meshed it in Strand7. If the units where in m, then it is 0.000059 m3.


       


      If you measure it in space-claim it is the same, but i n mm3.


       


       

    • ansysuser
      Subscriber

      Hey, that is great jj77.  I wish it were so simple in ANSYS!   I very much appreciate your help.  Unfortunately I need to do several of these so I still need a solution that uses ANSYS :-(


      Thanks again.

    • zjuv9021
      Subscriber

      I am also struggling with simple geometrical calculations such as area and volume changes over time.


      Does anyone have experience in this area?


      Thank you,


      Zach

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