6 Replies Latest reply on Apr 10, 2009 8:32 AM by Ameer Chilakala

    Sheet Metal Parts in Simulation Not Working Anymore

    Mike Lowinske
      Hi,

      I have a model consisting of some sheet metal, some surfaces, and some regular solid parts. In my static and frequency analyses cosmos will mesh those sheet metal parts and surfaces as shells (which is desirable) and of course the other solid parts as a solid mesh.

      Trying to do a linear dynamic analysis of the model now, however, cosmos will no longer treat those sheet metal parts with a shell mesh and it wants to mesh them as a solid, which of course I don't want because I can't get enough elements across the thickness to make the results accurate without cosmos generating nearly a million elements which takes too long. If I right click on the sheet metal part in the parts list it gives me a "Treat as sheet metal" option, but selecting it does nothing. Can anyone tell me why I cannot use a shell mesh like normal on those sheet metal parts in the dynamic analysis?


      PS I using SW2009 SP0
        • Sheet Metal Parts in Simulation Not Working Anymore
          Anthony Botting
          Hi Mike: As you probably found out, the shell modeling process is re-defined in 09, compared to 08. In 09, you have to explicitly create surface bodies (such as using 'offset surface' command), and explicitly add a "delete" feature to the solid bodies that you do not intend to be meshed with solid elements (alternatively after creating a study you can right click on the solid bodies and choose "exclude from analysis"). The study is supposed to automatically detect all surface and solid bodies and assign a mesh type based on its discovery. It has been a bit of a pita transition. It appears the "treat as sheet metal" command is not working on your model or due to some glitch in the body that won't let it complete. Good luck. Tony
          • Sheet Metal Parts in Simulation Not Working Anymore
            Mike Lowinske
            The treat as sheet metal command does not work for any sheet metal parts I have or even create brand new when doing a linear dynamic analysis. Can anyone else confirm this as happening under only linear dynamic?
              • Sheet Metal Parts in Simulation Not Working Anymore
                It is not dependant on the study type. When the sheet metal body is not created using sheet metal features or if the thickness is not uniform then the body cannot be treated as sheet metal. In 2010, we have a new command called define shell using selected surfaces similar to 2008. This command will solve your problem.
                  • Sheet Metal Parts in Simulation Not Working Anymore
                    Hi Mike,

                    Original post:

                    You might want to find out if Linear Dynamic analysis supports shell elements. For example, "Drop Test" in SW Premium with Simulation Professional doesn't support shell elements.

                    Update:

                    I found this in "help":

                    " To perform modal time history analysis:

                    Create a linear dynamic study. Right-click the top icon in the Simulation study tree and select Study . You can define a solid, shell, or mixed mesh study. Beams are not supported.
                    "

                    I don't have Simulation Premium, so I am unable to test, but it looks like shell elements are supposed to be supported for Linear Dynamic Analysis.

                    Hope this helps,

                    Dave.
                    • Sheet Metal Parts in Simulation Not Working Anymore
                      Mike Lowinske

                      jeyakumar krishnakumar wrote:

                       

                      It is not dependant on the study type. When the sheet metal body is not created using sheet metal features or if the thickness is not uniform then the body cannot be treated as sheet metal. In 2010, we have a new command called define shell using selected surfaces similar to 2008. This command will solve your problem.

                      That is good to know. I always had a better time meshing things in 08 than in 09