3 Replies Latest reply on Feb 13, 2011 8:47 PM by Jeff Byrne

    Shell element color and flipping

    Joe Rochinski

      Hello all,

       

      Solidworks Help states the following regarding shell meshes:

       

      To distinguish the top and bottom faces of the shell elements, SolidWorks Simulation assigns different colors to top and bottom faces of generated shells.


      Indeed, shell elements have a grey and an orange side. Unforunately, there are no details whatsoever which leaves me to ponder the following questions, which I hope some of you will be able to answer:

       

      • Which color is the top? Which is the bottom? Why does it matter enough to make a distinction?
      • Elements require a user-defined shell thickness. Does the software assume the element is located at the mid plane or on one of the surfaces of the simulated part? If the latter is true, does the element thickness grow out of the grey side or the orange side?
      • Under what circumstances should I use the 'Flip Shell Elements' command?

       

      Thanks in advance for any insight,

       

      Joe

        • Re: Shell element color and flipping
          Devi Prasad Samal

          Hi Joe,

           

          Though i am not a bit professional, but i have some understanding of the shell allignment.

           

          Actually shell allignment normally helps us for post processing of results. when we apply shell element and analysis them in the stress plot we can select top face , bottom face, membrane and bending stress distribution. Now again the question arise what is the use of checking top face and bottom face stress as they are always approx. equal. but if you take thickness greater sometimes the stress distribution varies from top to bottom face such as tension and compression.

           

          Actually this kind of post processing mainly helps in analysis of composite shells. you can check different layer of stress value in different type of surfaces top or bottom.

           

          Hope this info helps....

           

          and according to your question what is the use of shell mesh allignment...?  that's a big question for me also..if i find any answer, i will update u also.

           

          Regards

          Devi Prasad Samal

          • Re: Shell element color and flipping
            Joe Rochinski

            Since SW2011 added the ability to offset the shell element mesh from the actual surface bodies in your model, it becomes more important than ever to know which side of the element is the 'top' and which is the bottom'

             

            I'm not sure if this option was always present, but in Simulation --> Options -> System Options -> General there is a 'mesh colors' setting. So I can finally say with certainty that using default settings, the gray side of the element mesh is the 'top' and the orange side is the 'bottom'.

             

            Just thought I'd pass it along.

            • Re: Shell element color and flipping
              Jeff Byrne

              I've been wondering this myself. Mainly due to the enourmous difference in mesh time depending on wether "automatic shell alignment" is enabled or not. I understand that without the shell alignment, the model will have conflicting geometries in the real world, but how much would that effect a stress plot? Does the analysis just act as if an element is offset by its thickness, or does it muck up the stresses due to overlapping nodes?

               

              Reducing my mesh times from hours to seconds would be great, even If I have to manually flip the elements.