9 Replies Latest reply on Oct 4, 2017 12:19 AM by Ryan Dark

    Fixture for bolts?

    Eddie Chua

      Hi all. Is there anyway I should apply fixture to this cover for my pressure simulation?

       

      This cover here: https://imgur.com/M30hr8m is to be bolted onto this chamber: https://imgur.com/SXef2uV  (which I'm using inertial relief).

       

      So if I were to do an independent simulation for this ctover , what type of fixtures do I apply onto this?

       

      Thanks

        • Re: Fixture for bolts?
          Ryan Dark

          Hi Eddie,

          If you want to analyze your lid in isolation from the chamber you may want to make use of 'Foundation Bolts' (SOLIDWORKS Help - Connector - Bolt) as a means of fixing the model in space while you apply pressure to it.  This would require that you make a Virtual Wall (SOLIDWORKS Help - Contact Sets) for the bolts to bolt into.  The Virtual Wall in this case will represent the non-modeled chamber to bolt your foundation bolts into.

           

          Getting the stiffness right on the Virtual Wall so that it is representative of your chamber will probably be pretty tough.  For that reason you may want to analyze the lid-chamber as multi-body analysis with Bolt Connectors and a No Penetration contact between the two.

            • Re: Fixture for bolts?
              Eddie Chua

              Hi Ryan, thanks for the help.

               

              I've set the front plane as the virtual wall. Do I set the bottom face of the lid as the 'bonded contact'?

               

              Also, I did the bolt foundations for each of the 38 holes. However I could only select the circular edges on each side of the hole for the bolt head and nut position - there was no relation directed toward the virtual wall. Is that supposed to be it?

               

              Thank you.

                • Re: Fixture for bolts?
                  Ryan Dark

                  Eddie,

                  When defining the foundation bolt you should only have to select the hole edge on the nut side of the model (blue box below) and the plane that is your virtual wall (purple box below) like you see below.  These two selections, and some torque value should be all you need for the foundation bolt.

                    • Re: Fixture for bolts?
                      Eddie Chua

                      Thank you very much for the help. I seem to have managed to proceed with the simulation.

                       

                      Just some final questions for a double-check:

                       

                      1) Are these settings for the virtual wall correct? https://imgur.com/aO6J2m7 I'm concerned about the 'Faces, Edges... for Set 1' part, where I selected the bottom face of the lid. I hope it doesn't mean that I've made the entire lid connected to the Plane 1 (virtual wall)

                       

                      2) Bolt settings I'm quite confident there's no mistake, but here's a picture: https://imgur.com/mGoVOyh

                       

                      3) This warning came out when I run the study (Preload in at least one connector is zero. Do you wish to continue?): https://imgur.com/MHyXoas  . I just selected 'Yes' without any idea what it is.


                      Once again, thanks a ton for the help!

                        • Re: Fixture for bolts?
                          Ryan Dark

                          Eddie,

                          1. In the definition of the virtual wall the blue box is determining which faces/edges of your model interact with the plane in a No Penetration contact.  You will still be able to have lift off from the plane; it is not a bond from the face to the plane.
                          2. The bolt settings you show don't seem out of the ordinary.  They are not all shown
                          3. At least one of your bolts has no preload applied.  This would invalidate your results as Bolt Connectors in Simulation are only valid when the bolt is put in tension.  If it is zero preload or allowed to lift off then the formulation for the theoretical Bolt Connector is invalid.  You would want to inspect all your bolts and make sure non-zero preload values are applied to all.