5 Replies Latest reply on Feb 4, 2009 10:08 AM by 19109

    Mixed Mesh Troubles

    Brendan L
      Hello all,
      I am new to using CosmosWorks (at least still green behind the ears) and I am trying to use a mixed mesh study. I am creating a wing with solid meshed structural components and a shell meshed wing skin. However, when I mesh and run the Cosmosworks, the skin and the structural components aren't interacting. I have globally bonded setup. I am at a loss as to what to do next to solve this issue


      Brendan
        • Mixed Mesh Troubles
          For the globally bond setup to actually bond the two together the the skin and the structural components have to have face to face contact. You may have to create contact sets between the components.
            • Mixed Mesh Troubles
              Why face to face only? It should work also with a border of a surface in contact with a face of a solid. I have some cases in which this work, and other ones in which it does not work and I do not know why. And if I attempt to create such a contact set I cannot because it is not posssible t select a border in the proper property manager.
              The documentation for 2009 Sp2.0 claims that the software sets automatically the contacts between solids, shells and beams. I believe that for beams this is definetely false. Moreover if I create a contact group beam/surface and the surface is not planar the program says (at resolution time!) that this is not allowed.
              For contacts shell/solid (over a border) I observe an erratical behaviour: sometimes this works and sometimes not.
              Anybody knows some more detailed and reliable documentation?
              Thanks
              Leonardo Presciuttini
            • Mixed Mesh Troubles
              From the Simulation Help file.

              Use the Global Contact PropertyManager to set the default contact condition between touching faces of different parts in an assembly document or different bodies in a multibody document. It sets the contact condition at all areas that are common to two faces. It does not set any contact conditions for two faces that touch each other along a point or edge or if the area of contact is extremely small
                • Mixed Mesh Troubles
                  Wayne,
                  I believe that the Global Contact PropertyManager is not useful at all with mixed mesh problems.
                  Simulation help file claims, if I remember well, that the program sets automatically a bonded contact between a) border of a surface (shell) and face of a solid (meshes not congruent), b) border of a surface (shell) and border of a surface (shell) (meshes congruent), c) end of a beam (from weldment) and surface (shell).
                  In my experience a) is often true (I have cases in which on the same model this works somewhere yes and somewhere no); b) is often false and c) is never true.
                  For case b) I get bad results when the topology is somewhat complicated and when I have shells crossing in a T shape (on this topic an article of the simulation help seems to me inaccurate and confusing).
                  For case c) I must always impose a local contact group, and moreover the analysis will be stopped at solve time if I have bonded contacts between beams and non-planar surfaces (see attachment).
                  Regards
                  Leonardo
                • Mixed Mesh Troubles
                  Brendan L
                  Thanks guys for all your help. When I added the contact sets it worked right.