3 Replies Latest reply on Dec 23, 2014 3:41 PM by Michael Kalin

    Simulation Pop-ups concern or ignore?

    David Hooper

      Simulation Pop-ups concern or ignore?

       

       

      My end goal is to run a dynamic analysis on a very large system.  First, I simplified the system the most that I could including making many remote masses and shells.  I started analyzing my subassemblies each individually with frequency analysis and sometimes static analysis just to check the model.  I have been combining the assemblies and adding complexity as I go.  I have had the fun of just restarting solidworks and my "errors" go away many times.  Now, that I am increasing in complexity I have the following problem.  I get several pop-up windows when I try to solve the study. 

       

      "Error in transferring special loads"

      OK

       

      "One or more selected entities of sheet metal for Connections, Fixtures, and/or External Loads cannot be mapped to midsurface entity" 

      OK

       

      I hit OK on both and the system appears to run ok, but should I be worried.  I would prefer to fix any issue prior to adding more and more complexity and definitely prior to running the dynamic analysis.    The only special loads that I can think of are my remote masses?

       

      I tried to add more complexity yesterday and got "Frequency calculation with loads is unavailable with iterative solver. use sparse solver", which was strange considering I was using remote loads on the smaller subassemblies and had no issue.  I am using iterative solver with more accurate bonding.

       

      The DOF is 1.4M, Nodes 341k, Elements are 324k.

      I am running SW 14 SP5. 32 Gig ram, Intel Xeon CPU E5-2630 v2 @ 2.6GHz Windows 7

      The path name is this long.

      C:\XXXXX\XXXXXXX\Projects\XXXXXXX XXXXXXXX XXX system 10-20-2014\XXX-Frequency Analysis Simplified

       

      Any help would be appreciated because I am very behind due to: Motherboard going bad, SSD going bad, and major difference in SW14 S2 to S5. I have recovered from them all but now am really behind.

       

       

      Note: found out that my support ran out without knowing about it until I needed it.

        • Re: Simulation Pop-ups concern or ignore?
          Michael Kalin

          When you added more complexity, did that include sheet metal parts and additional loads? The errors sound like they are telling you that some connection/fixture/load is improperly attached to a shell entity. The error for the frequency calculation has nothing to do with the bonding condition; it has to do with predescribed loads.

           

          1.4 million Degrees of Freedom is very high. For reference, the cut-off between the more accurate Sparse Solver and the Iterative solver is 100,000 DoF. Running such a complex mechanism all at once may be unfeasible. I would suggest running parts or sub-assemblies individually and recording their results on boundary conditions, such as where they are attached to another part, then inputting those results as base excitations in another study.

          • Re: Simulation Pop-ups concern or ignore?
            David Hooper

            Michael,

             

            Thank you for replying I really appreciate you taking the time to answer.  The error popped up when I added some solid parts to my assembly.

             

            All the errors went away when I removed the remote masses from the frequency calculation and I achieved the solutions I was looking for.  I did not consider the remote masses as external loads but apparently they are. 

             

            Since the frequency analysis is only used as a check on my system it served its purpose.  I am unsure on why the remote masses affected it since early in the process they seem to solve fine.

             

            Now I have moved on to using the model in my linear random vibration analysis.

             

            Thank you for your suggestion on breaking down the system I understand how it would work on a strictly vibration analysis, but unsure if it would work on the random vibration analysis.

             

            Respectfully,

             

            David

              • Re: Simulation Pop-ups concern or ignore?
                Michael Kalin

                It would be unrealistic to do it for a random vibration with a reasonable degree of accuracy. You might considering calling your VAR; they could suggest methods to cut down on the total number of features/elements. Perhaps you could also consider outsourcing it if the entire size of the assembly is too large for SolidWorks to handle.