4 Replies Latest reply on Mar 2, 2018 4:17 PM by Keith Frankie

    Unknown Mesh Icon

    Aaron Gradeen

      Hey Guys,

      I've been fiddling with thermal loading on a very simple cylindrical rod representing a cable. If I apply a temperature decrease of say, 100 K, I know what strains should show up in the cable as it's fixed at both ends. I ran the study and got much smaller reaction forces at the two fixed ends. After pulling my hair out over it for a couple hours, I started another study from scratch and got the expected results. Looking back on all the other incorrect studies, the only difference I could see was an icon beside the part in the simulation feature tree. Check out the picture below. Mesh shows up fine on all four solid bodies. But that icon looks incorrect. Isn't that the icon for a remote mass? Any idea why that icon is there? Typically that blue cube represents an icon for a solid body.

       

      When I recreated the study from scratch, I got the correct icon beside the solidbody.

      here's a snapshot of the mesh of the cable for the study with incorrect results. Each solid body just represents a quarter slice axially down the cable.

      All loads, fixtures and materials are identical between the two studies. I apply the temperature to each of the four solid bodies. Does anyone have a clue about what's going on?

      Thanks

        • Re: Unknown Mesh Icon
          Ryan Dark

          Hi Aaron,

          These mesh icons represents a body that has been rigid in your analysis.  So, you might expect that these bodies will not deflect and cause the overall analysis to be more rigid and have smaller then expected displacements.  Typical icons for solid bodies you see on the two bodies above these; the ones with yellow cube icons.  If you right click those bodies in the list and select "Make Deformable" you will probably get some better results.

           

            • Re: Unknown Mesh Icon
              Aaron Gradeen

              Thanks for the input, Ryan. I think it's a bug in the program. I don't actually have that option. And I never made those rigid in the first place. I did temporarily switch them to beam elements though so maybe the issue lies there. I think that's the best answer I can get.

                • Re: Unknown Mesh Icon
                  Ryan Dark

                  It is odd this command is missing.  As you already found though (and I agree) it is probably the source of your odd results.  I'm not sure why it would not let you pop those out of rigid mode though.

                    • Re: Unknown Mesh Icon
                      Keith Frankie

                      When the 'make rigid' option is selected SW turns the exterior faces of the body into a shell mesh and fixes everything.

                       

                      Here's an experiment: draw two rectangles on the front plane, extrude that.  In simulation turn one of the bodies into a rigid body.  Mesh using default settings.  Create a mesh plot of the mesh itself.  Choose 'mesh sectioning'.  You can verify that the mesh section shows up on the solid body, but not on the rigid body (since it's actually a shell mesh, and there's no mesh to section).

                       

                      So the question then becomes, on the file you were having trouble with, is the 'make rigid' option actually taking effect?  Check to see if there is a mesh in the middle; if not, then indeed the option got toggled on somehow.

                       

                      Also, if you copy your known good study and make the bodies rigid (as seems to be occuring in the problematic study) do your results look the same as the problematic study results?

                       

                      In my experience with SW sim this kind of GUI / interface error does occur occasionally, and of course it's always frustrating.