9 Replies Latest reply on Dec 29, 2016 6:38 PM by John Dixon

    Phantom contact sets?

    James Denney

      I have a contact set that is defined as beam joints bonded to a flat plate. Whenever I run my analysis, the beams are displacing, so I'm guessing they aren't truly bonded. Odd thing is I had this exact same contact set defined in a previous iteration of this model, and it worked fine. I do get a cryptic message "beam joint cannot be projected onto surface"...I'm guessing they are related? Anyone encountered something similar before?

        • Re: Phantom contact sets?
          John Dixon

          I have the same problem.  Did you get this figured out?

          • Re: Phantom contact sets?
            Seckin Uslu

            Could you please share some pictures about study.

             

            Did you try increase the mesh size?

              • Re: Phantom contact sets?
                John Dixon

                Image is below

                Increase in mesh fines resulted in error.

                I have used a alternative method for the simulation, due to the many hours of time spent attempting to alleviate the issue.  I am not experienced enough with Solidworks to set up contact sets that will work consistently at this time.

                Originally, I attempted to mesh "structural components" with "Extruded boss/base."  The "structural components" consisted of angles and channels that were created using the Insert--->weldment--->structural member tool.  I was able to get it to mesh by creating contact sets manually.  However, a successful mesh could only be obtained with the mesh adjustment bar (i.e.coarse to fineness) positioned mid-way.  As a work-around, I modeled all of the structural components as "solids" - see image below.  Additionally, I am using mesh control to help minimize the mesh fineness where not needed.  Although the simulation takes a little longer to run, it is working well and has produces deformations that I had expected.

                 

                 

                  • Re: Phantom contact sets?
                    Bill McEachern

                    this stuff is all trivially easy to get done if you understand how the program works:

                    1. any surface that is coincident with another surface will automatically get the default contact condition (typically bonded if you do nothing to change it).
                    2. Any small (>1e-8) gap will will have no interaction specified and will require moving it to remove the gap or a manual contact to be specified.
                    3. You can capture and specify surfaces in close proximity with the find contacts automatically option in the manual contact options.
                    4. Understand the contact hierarchy: manual contact over rides a component contact which over rides a global contact. Oh and component contacts strated to not work back in say 2008, I am not convinced they have been robustly fixed).
                    5. Solid elements mesh on solid parts.
                    6. Shell elements mesh on surfaces.
                    7. Beam elements mesh to structural members
                    8. In my experience it is hit or miss if different elements will follow the default contact condition - that is to say beams will automatically bond to say a shell surface - sometime it works, sometime it doesn't.
                    9. Beams to solids - same thing
                    10. Shells to solids - almost never works but I am still using an older release.
                    11. If you are having trouble manually connect different element types. Run a frequency analsys to see what is not bonded, use the show contact plots to see what the program thinks it should have as bonded or no penetration.
                    12. You can you the interference tool to check whether things are coincident or not.

                    I did a presentation at SWX World a few years ago on how all this stuff works. Not many people showed up and those that did needed a can of red bull to stay awake (which I brought in the vain hope that somebody might stay awake long enough to learn something).

                • Re: Phantom contact sets?
                  John Dixon

                  James, did the dialog in this discussion help you with your question?