3D Design

3D Design

Convert Multibody CAD import into Parts for improved Contact/Joint creation

    • peteroznewman
      Subscriber

      I use NX11 to prepare geometry for import into ANSYS Mechanical. The original CAD files are an assembly, but the Best Practice in NX is to create a new top level file and link only the bodies from the assembly that are needed in the analysis. When that one file with multiple solid bodies is brought into ANSYS using the NX-ANSYS geometry interface, a single multibody part is created, though the solids usually represent separate parts. This causes a problem when creating contacts or joints because the Body Views can't show two different parts for the Contact and Target side because there is only one part in the model. In the scissors mechanism example below, two faces that bond a journal bearing to the arm have a bonded contact defined. Note how the Body View on the right side is not very useful.



      I recommend after importing the NX geometry, to Edit in DesignModeler, then use the Explode Part feature to convert 1 part with 30 bodies into 30 parts with 30 bodies.  Then in Mechanical, that same contact definition (shown below) now has very useful Body Views.


    • peteroznewman
      Subscriber

      Here is the screen snapshot of the Explode Part feature in DesignModeler. I wish I could do that in Mechanical instead of having to go out to DesignModeler.


      You must do this operation at the beginning of the model building process. If you do it after creating some contacts or joints, they will all lose the selected geometry after the Explode Part and will have to be repaired.



      I expect there is similar functionality in SpaceClaim, but I have not looked for that yet.

    • peteroznewman
      Subscriber

      The benefit of better visibility of the faces during contact/joint editing after using DesignModeler to Explode Part comes with a cost.


      Without DM, updating the geometry from NX was a one step process.



      • RMB Update Geometry from Source


      After DM, updating the geometry from NX is a seven step process.



      • Switch to Project Page

      • Open DM from Geometry row

      • Pick Attach

      • Change Details for Refresh

      • Click Generate

      • Switch to Mechanical

      • RMB Update Geometry from Source

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