Preprocessing

Preprocessing

Meshing areas, complex geometry

    • joepa_2017
      Subscriber

      I have run into the following error:


      "Unable to mesh area 1 because of shape problems.  It may help to change element size on edges of area."


      I would like to know if there is a way in APDL to change element size on edges of area.  I assume this would mean that the mesh would be much more fine at the edge of an area while interior elements may not be so refined.  However, I don't know how to implement this, aside from refining the mesh along lines after creating an initial mesh.

    • Sandeep Medikonda
      Ansys Employee

      Hello,


      Mesh Sizing on the command line or input file includes the following commands:



      • Use ESIZE to define default global mesh size applicable to regions where local mesh size controls have not been defined

      • Use KESIZE, LESIZE, AESIZE to assign local element size at keypoints, on lines and areas, respectively

      • Use EREFINE, NREFINE, KREFINE, LREFINE, AREFINE to refine existing meshes at elements, nodes, keypoints, lines, and areas respectively

      • Use KCLEAR, LCLEAR, ACLEAR, VCLEAR to clear existing meshes at keypoints, lines, areas, and volumes


      So, let's say you want to gradual size transition on let's say area 6 in your model:


      ESIZE,0.4 ! GLOBAL MESH SIZE = 0.4
      ASEL,S,AREA,,6 ! SELECT AREA #6
      ALLSEL,BELOW,AREA ! SELECT ALL ENTITIES USED BY AREA #6
      KESIZE,ALL,0.1 ! AREA #6 CORNER KEYPOINT MESH SIZE = 0.1
      AESIZE,6,0.1 ! AREA #4 MESH SIZE = 0.1
      VMES,ALL ! MESH ALL CURRENTLY SELECTED VOLUMES

      You can find some more examples here.


      Hope this helps?


      Regards,


      Sandeep


       

    • joepa_2017
      Subscriber

      Will this make all elements on Area 6 have equal size?  That is, will all of the elements in Area 6 have a maximum size of 0.1?  I would like to have a very fine mesh at one boundary of the area, for example, and then let the mesh become more coarse moving away from that boundary.

    • Sandeep Medikonda
      Ansys Employee

      Yes, this would make the elements on area 6 have a smaller size i.e, 0.1 and gradually grow to 0.4 as we move away. You can always do this with lines if you need just the boundary.

    • joepa_2017
      Subscriber

      Cool, I see that this process works for gradually changing the mesh size, thank you!

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