12 Replies Latest reply on Jan 24, 2016 12:47 AM by Shawn Murphy

    Spot Weld Error (Sheet Metal Analysis)

    Kanisius Raychitra

      Hi. I am studying Car Body Structure that consists of multiple sheet  metal parts. All of the parts are in sheet metal form and they are connected by spot welds.

      It can mesh properly. However, when I run the analysis, it has error like this:

       

      " Cannot build Spot Weld. Check for gaps"

       

      I recognize that in Sheet Metal form, it will mesh at mid surface,. This will leave gap about 1/2 thickness of the sheet metal when it meshed.  On the other hand, the spot weld location is specified at the intersecting surface not at mid surface.

       

      COSMOS Companion told that I need to specifiy the surface location, but I think in Sheet Metal everything is fixed at Mid Surface. I tried changing it but it has no effect.

       

      Anyone can help me to get rid of this error? Thanks!

        • Re: Spot Weld Error (Sheet Metal Analysis)
          Jared Conway

          version/service pack?

           

          cosmos companion is back from like 2004/2005, there have been a lot of changes since then

           

          your parts should basically be resting on each other for the spot weld to work

           

          maybe you aren't selecting the appropriate faces?

           

          please post your model

          • Re: Spot Weld Error (Sheet Metal Analysis)
            Rajesh Raj

            check list

            1) treat as sheet metal

            2) welding face must be in no penetration

            3)no gap allowed in mate

            4) check weld dia like that properties

              • Re: Spot Weld Error (Sheet Metal Analysis)
                Kanisius Raychitra

                Hi Rajesh,

                 

                Can I ask you if you are able to make and analyse this simple model? Solidworks does not allow me to make spot weld because of the same error.

                 

                Two sheet metal that is spot welded among each other.

                 

                1. Both of them is treated as sheet metal (mid-surface meshed)

                2. No penetration is applied.

                 

                If you are able to do it, may i ask if you can provide step to step about it?

                 

                Thanks!

                 

                UPDATE: Somehow, I manage to correct the error by adding split lines.

                  • Re: Spot Weld Error (Sheet Metal Analysis)
                    Jared Conway

                    post your simple model and the one you fixed so that people that have this problem in the future can take a look

                     

                    it sounds like maybe there were too many contact elements? i'm not really sure i'm clear on what a split line would do to fix the issue

                      • Re: Spot Weld Error (Sheet Metal Analysis)
                        Kanisius Raychitra

                        Dear Jared,

                         

                        Ok I'll post the model soon. But, tbh, I really dont know why the problem is gone.

                         

                        Now my concern is:

                        The solver stuck on "Solving Contact Constraints" in 20% progress. Meanwhile the overall study progress stuck at 27.3%.

                        As you have said,  my model has too many No Penetration contact sets among each panel parts which cause this problem.  The number of D.O.F is quite large (about 3 Million D.O.F). I have searched on the forum, and they stated to check if there is anything that cause the problem using draft-quality mesh. The run using the draft-quality mesh can be finished and the results is out. (So, I assume that it is because too many DOFs)  I also know that the draft mesh results wont be accurate.

                         

                        Hence, do you have any suggestion to handle this problem (maybe the meshing etc)? I dont know any method to reduce the D.O.F anymore because I have used shell-meshed, half-model, etc. and the D.O.F is still high. I also tried adding split lines and use Control Mesh for crucial area only (like the contact points) in order to reduce number of elements . But the problem persists. I really need your help and I cannot afford switching to other softwares.

                         

                        Also, I am not allowed to alter No Penetration contact because it won't be a proper modelling. Basically, this is for the university's final year project.

                        Thank you.

                  • Re: Spot Weld Error (Sheet Metal Analysis)
                    Shawn Murphy

                    I'm having a similar problem on using the on-line tutorial "Spot Weld Connectors".

                    1) If I run the simulation as the tutorial states. I get this gap alert.

                    Gap alert.jpg

                    It allows me to continue and get the this result which closely matches the tutorial results.  See screen shot for notes.

                    Spot Weld of Automobile Parts-4.jpg

                    2) I reset up the simulation per the following, see screen shot for notes.  Here I did not get the "Gap alert", but the welds are not stressed at the end like I would expect.

                    Spot Weld of Automobile Parts-4a.jpg

                    Questions:

                    1) Which one is to correct set-up?

                    2) Is this gap alert normally ignored?

                    3) Is there a different setup to avoid this gap alert.

                     

                     

                    Software is SW2014