10 Replies Latest reply on Nov 4, 2013 11:12 AM by Jared Conway

    Multi body part simulation

    Doug Rawlings

      Hi,

       

      It seems that all I do at the moment is ask awkward questions abot SolidWorks. Here's another one.

       

      I've got a thermal Simulation task for which I'm using a multi-body part.

       

      It was going fine, seemed to work OK. But then I added another two bodies and it has stopped working. Every time I try and run it tells me "Please define Thermal conductivity in material properties". But I can't find which material is missing this.

       

      I've tried a few things like excluding nodies from the analysis or setting the material in Simulation but I can't find any pattern to what's happening.

       

      I've even tried deleting the bodies that I'd added when it first started to fail, but I can't get it to go back to where I was. Unfortunately I didn't back up adequately. I thought I heard of a way of stripping Simulation data from a part file, but I've tried the way it worked for me before and it's not working this time.

       

      Is there some limitation on the number of different materials you can have in a multi body part for Simulation? Or am I doing something else wrong?

       

      When I tried running a Static load case on the same part it told me that an Elastic Modulus was missing.

       

      The study was initially done as 2D simplification axisymmetric but I've tried full 3D without any improvement.

       

      SolidWorks Premium 2012 x64 Edition SP2.0

      (Simulation Professional)

       

      Any suggestions would be appreciated,

       

      Regards,

       

      Doug.

        • Re: Multi body part simulation
          Jared Conway

          if you're creating a new study, the bodies should all inherit the part material. if you have an existing study, you may need to apply the materials manually. i'm assuming you've checked the material but if you haven't make sure to do that because you're seeing a problem at the static and thermal level.

           

          my guess would be a geometry or study issue so here's a few things to check:

           

          if it is an imported part, does it survive an import diagnostic?

          does it survive a ctrl-q with verification on rebuild?

          export the model as a parasolid and reimport and apply the material, see if that fixes the problem

           

          if any of those come up with issues, make sure those are fixed before you move on.

           

          for the study, make a new study, see if that fixes the problem

          in the new study apply alloy steel or similar and make sure that works. (could be the material you are using)

          if you have this part inside another assembly, check what happens at the part level

           

          if all of this fails, post your model, this could just be a 2012 sp2.0 issue. that is 9 service packs ago.

            • Re: Multi body part simulation
              Doug Rawlings

              Jared Conway wrote:

               

              if you're creating a new study, the bodies should all inherit the part material.

              yes, that's what I initially had.

              if you have an existing study, you may need to apply the materials manually. i'm assuming you've checked the material but if you haven't make sure to do that because you're seeing a problem at the static and thermal level.

              when I had problems with the inherited materials I tried applying them manually in the study. If I tried to apply one with no thermal conductivity defined it warned me at that stage - but all the materials I used did have this property

              my guess would be a geometry or study issue so here's a few things to check:

               

              if it is an imported part, does it survive an import diagnostic?

              No, it's not an imported part

              does it survive a ctrl-q with verification on rebuild?

              Yes, no problem

              export the model as a parasolid and reimport and apply the material, see if that fixes the problem

              Exported, imported (passed Import Diagnostics no problem) applied materials in SW and no difference

               

              if any of those come up with issues, make sure those are fixed before you move on.

               

              for the study, make a new study, see if that fixes the problem

              I've tried a variety of new studies.

              in the new study apply alloy steel or similar and make sure that works. (could be the material you are using)

              If I apply a material using “Apply Material to All Bodies…” it'll run. I've tried that for each of the materials I'm actually using. If I apply Alloy Steel to each body individually.

              if you have this part inside another assembly, check what happens at the part level

              It's just a part

               

              if all of this fails, post your model, this could just be a 2012 sp2.0 issue. that is 9 service packs ago.

              The place I'm currently working (I'm a contractor / consultant) has chosen not to maintain their SW (I have my own licence) for various reasons.

               

              Since the job is axi-symmetric I've tried using just sketches and running those. But in that case Simulation doesn't let me assign materials correctly. I'll assign a few and then it gets to a stage where I try to assign a material to a body and it either assigns it to a different body or doesn't assign it at all. Then when I run it the results omit the parts that it wouldn't let me assign a material to. Again, if I use the “Apply Material to All Bodies…” then it works fine, but that's nothing like the actual simulation I need to run.

                • Re: Multi body part simulation
                  Jared Conway

                  in 2d simulation you still use the solids (not sketches)

                   

                  sounds like a software specific issue, if you want to post the model others cna check in later versions

                   

                  workaroud for now, take your multibody part and save the bodies as an assembly

                    • Re: Multi body part simulation
                      Doug Rawlings

                      Actually you can go straight to a 2D simulation from sketches. I've got an axis defined at the intersection of Front and Right planes, then several sketches on the Front plane. 'New Study' -> axisymmetric -> Front plane -> Axis1 and there's the study. You can sometimes (!!) do it with one sketch with multiple regions but it doesn't always recognise the regions correctly.

                       

                      But that's giving me problems as well... I've got all the materials applied to the right parts and it runs but for some reason it applies the loads to the wrong entities. When I show the load you can see it's clearly applied to a different entity to the one I'd selected. when I edit that load it sometimes shows the load markers in the correct place but sometimes (just to wind me up) it highlights the entity I want and shows markers on the other entity.

                       

                      I'm going to try a different PC, the one I've been suing so far doesn't have much memory but other than that I'll try the assembly route.

                        • Re: Multi body part simulation
                          Jared Conway

                          i suspect a 2012 issue here. posting an example will help you confirm this if someone else is able to run it.

                           

                          good tip about 2d simplification and sketches, in the 3-4 vesrions that we;ve had that functionality, i've never seen someone use it! most people model in 3d and then simulate based on 3d.

                  • Re: Multi body part simulation
                    Doug Rawlings

                    Well, I've made some progress to the original problem; it's not a nice solution but it works and that's the main thing for now.

                     

                    1. Take the study that complains of "Please define Thermal conductivity in material properties"
                    2. Assign materials through Simulation but only using standard SolidWorks materials
                    3. Try running the study
                    4. Re-assign the custom materials to the parts that need it
                    5. Try running the study
                    6. If it works, great; if not repeat from step 2.

                     

                    Sometimes it takes a couple of cycles through to get it to work.

                     

                    Doesn't make any sense to me but at least I can get some results. But having to go through this sort of procedure always makes me concerned about the quality of the results.

                     

                    Regarding the other problems, I contacted my VAR (I have a seperate licence). Unfortunately all they suggested was to revolve the sketches and makes bodies from them! I can't get the 3D model to mesh so have to use 2D simplification which brings me full circle to the problem I had in the first place.

                     

                    I'll keep going and post any developments.

                      • Re: Multi body part simulation
                        Jared Conway

                        "Doesn't make any sense to me but at least I can get some results. But having to go through this sort of procedure always makes me concerned about the quality of the results."

                         

                        having a good idea of what the results should be should help here. also, you could use the report function to check the applied materials. you may even consider some point tests on individual parts (the rest excluded) to test that they work the way you expect.

                         

                        if you've got a separate license, why not run this analysis with the latest and greatest version to see if it is a software issue or to get some support on it? seems like even if your client doesn't have subs, it would have paid for itself with the troubleshooting you've done so far and your concerns with the results.

                          • Re: Multi body part simulation
                            Doug Rawlings

                            Yes, I've got a reasonable idea of what the results should look like but I'm looking for details in the model.

                             

                            It seems to be running rerasonable reliably at the moment. It's just that every now and again I have to re-apply materials.

                             

                            My licence is for SolidWorks Standard, so doesn't cover Simulation. I tihnk the only reason the VAR has agreed to look at it iss to try and win back the business, but it's not looking good so far since most progress has been made through this forum or my repeated experiments. I don't know if they're having the same issues as I do if they run it on SW2013, I think they have a couple of issues.