7 Replies Latest reply on Jul 15, 2013 4:19 PM by Mike Pogue

    Solidworks Simulation query!

    David Flemming

      hey guys, how are you all? I'm new here and have a question as I have recently started using Solidworks Simulation...when i run an analysis in solidworks and the FOS is above 1, why does it still show me a displacement in the animation feature. I think that if the FOS is greater than 1 then the product wont fail of have any displacement (wobbling or bending). But on matter how small a force i use it still shows me a movement. Can someone answer WHY?

       

      Thank you all in advance

      David

        • Re: Solidworks Simulation query!
          Mark Kaiser

          Depends on a lot of factors, but, materials yield before breaking, and move during yielding.  Not a sw simulation problem you're having.

          • Re: Solidworks Simulation query!
            Shaun Densberger

            Is it that the defelction looks too big or that the values given are too big/non-zero?

             

            If it the the former, then Mark has the right answer; the visual deflection is almost always scaled up so that the user can see it.

             

            If it is the latter, then it depends. If your issue is that the numbers are too big (larger than what you would expect), then that could be from a number of issues. I'd start off with checking the units on your loads an materials. If you applied a load to multiple surfaces, then make sure that it is set to total load and not load per surface.

             

            If your issue is that the deplacements are non-zero, then you don't have anything to worry about. Any material (regardless of how stiff it is or what shape it is in) will deflect under any load (regardless of how small it is).

            • Re: Solidworks Simulation query!
              Anthony Botting

              Hi David:
              Everyone is correct.

              To answer your question directly, there is a setting in menu item "Simulation...Options" that should reveal why you are 'seeing' a movement regardless of stiffness or load values. See image below. The software is set from the factory to automatically show a 'deformed shape'. This image shows the global control for default behavior of generated plots. You can also set a local control (for a particular plot) by right-clicking on the plot icon in the tree, and choose 'edit definition'. There you should see a panel with "Deformed Shape" controls. Hope that helps. SimulationOptions.png

              • Re: Solidworks Simulation query!
                Mike Pogue

                I think one thing needs to be emphasised. Any force applied to any structure in FEA will cause finite deflection. This is true by definition, and you should clearly understand it. For instance, if you simulate an ant walking across a 2 ft tall titanium I beam, the ant will cause a small deflection in the I beam. This is a direct consequence of the elastic material model.

                 

                The factor of safety is based on the yield stress. This is not the stress at which the part begins to flex, but the stresss at which the part begins to take on permanent (i.e., plastic) deformation. It is closely related to the proof strength.