6 Replies Latest reply on Jun 12, 2008 10:47 PM by Bill McEachern

    Best way to Model Simply supported beam?

    Pete Swift
      What is the best way to analyse a simply supported shaft with a couple of loads on it? It is supported on spherical bearings.

      I have tried a couple of strategies

      1 drill a hole though the neutral axis and apply the load. I believe that you an use split face but have not done this.

      2 model it as half a beam cantilevered from the middle but this only works with a symmetrical loads and supports.

      What does everyone else do?
        • Best way to Model Simply supported beam?
          Basil Gello

          what types of loads do you want to model? If the problem is to investigate the bearing behavior, why not to use CosmosMotion with Toolbox bearing calculator? Refer to similar CM posts... and when you get the reaction forces, perform a nonlinear or any other analysis you want

            • Best way to Model Simply supported beam?
              Pete Swift
              A shaft was probably a bad example.
              I it really a simply supported beam question regarding pin jointed supports. Does restraining the ends via a hole allow the centres to move together?

                • Best way to Model Simply supported beam?
                  Martin Stokes
                  Have you tried using the beam elements in COSMOS?

                    • Best way to Model Simply supported beam?
                      Vince Adams
                      Hi Peter, this is a tricky restraint but an important one to know. The problem comes from the difficulties in controlling both translations and rotations on a solid face.

                      If you are in SW/CW 2008, open up the Design Library (Task Pane) and open the Examples folder in the Analysis Library branch. If you open the Crankshaft model, you can see a couple of ways to set this problem up.

                      As an FYI, these examples have several studies in each with different ways of attacking the same problem. Each study has some discussion of its validity in the Study-Properties-Remarks tab. The fourth case, Remote Load, is relevant to your question. By using Remote Load-Displacement, you can control the behavior of a face as if it is a point, thus enabling rotations as if it was a sphere or a cylinder while enabling longitudinal translations (Z translation in this case.)

                      This is a pretty powerful tool in CW and I've talked about it in 2-3 COSMOS Companion sessions. Let me know if that makes sense. If you aren't in 2008, browse the COSMOS Companion on Loads & Restrants Part 2.

                      I'd be interested to get the whole group's feedback on these examples and this method for delivering tips (Library parts with pre-configured studies.) Did anyone know they were there? What other techniques should be included?


                    • Best way to Model Simply supported beam?
                      Bill McEachern
                      solid elements have no rotational degrees of freedom so you need to do it with geometery or use a remote load/restraint to get the object to have free ends or whatever you want.

                      punch two holes in the ends and apply pin restraints or do the same thing without changing hte geometry with a remote load. Hope that helps. See the help file for how to work the remote load/restraint command.
                  • Best way to Model Simply supported beam?
                    Francesco Rustichelli
                    Vince, what I really dream of is a connector working like a remote load:
                    it could let me manage everyone of the 6 DOF.

                    It could allow the creation of a spherical joint, or of a pin between any couple of surfaces (not just cyl's)

                    If it worked with shells too, it would be wonderful :-)