2 Replies Latest reply on Mar 8, 2018 4:03 PM by John Leigh

    Elastic Support Clarifications

    John Leigh

      I work on simulations that sit on tall steel fabricated columns. This is primarily to try improving my understanding of what precisely the elastic fixture support does to help explain to my companies PE who uses a completely different analysis software. He isn't entirely comfortable with the wording SW has for inputting stiffness values and is concerned that this means the stiffness value stays normal to the face continuously as the program runs the calculation and the planar face the constraint is applied to rotates. however slight the movement may be.  He is used to seeing the following for spring supports. He isn't confident the elastic support is the equivalent to this.

       

       

      PE's Simulation elastic support input

      SW Simulation Elastic support

        • Re: Elastic Support Clarifications
          Bill McEachern

          It would seem that the other program is applying the elastic support to a node as opposed to a surface, hence the need for a rotational degree of stiffness - its a bit hard to tell though. If a surface is used roughly normal to the support, as is typically the case in SWX Sim the moment would be accounted for by the span of the elastic foundation (one side goes up and the other down). Why not run as nearly identical analysis as you can in both and see how they compared? More information about he other program might be helpful. If the analysis is linear (small displacement assumption) neither program will account for the rotations.

            • Re: Elastic Support Clarifications
              John Leigh

              We are presently running multiple analysis that are nearly identical to compare.  Hs program allow him to work from either a node or an entire surface.  The rotational stiffness is a separate option he is able to use with his software.  We are talking specifically linear stiffness at this point in time.  We do not tend to work with many torsional springs.  I would agree and he has effectively stated as much small displacement assumptions the change in the plane should not affect the current results we are working with. we are just trying to have a proactive discussion to try understanding the tool better to head off future concerns about this tool.  Which for all intents and purposes is highly likely.