2 Replies Latest reply on Aug 13, 2013 1:20 PM by Chris Michalski

    Displacement visualization not matching scale

    Chris Michalski

      Okay, I have a flat 3-layer laminate being put into 4pt bending.  Defined vertical displacement of the ends of the 2 center rolls is 5mm, end rolls constrained by a bearing support at the ends.  For reference, the laminate is 6mm thick and the rolls are 8cm diameter.  The 2 center rolls are on the top plane initially and their displacement is defined relative to the top plane.

      5mm setup.jpg

      Resulting displacement colors indicate 5mm displacement.  Deformed model  set to Truescale (also tried scale of 1 just to be sure) is hugely exaggerated.

      5mm displacement.jpg

      So those deflections are NOT truescale.  If I run a video it is not even starting at the starting point shown in the first picture, it has a major initial displacement.

       

       

      Any hints as to what is going on?  Why does it appear to start with a wildly deformed model before implementing the 5mm displacement?

      I'm not extremely experienced with mechanical simulations so either I've overlooked something or SW has an attitude this morning.  I'm willing to accept either answer, but right now I'm clueless as to which of us is crazy.

        • Re: Displacement visualization not matching scale
          Jared Conway

          hi Chris, your video got deleted.

           

          if you've got not error messages my first thought is to check the settings for the bearings and to check if soft springs is enabled.

           

          also assuming here you don't have gravity or anything enabled.

           

          what constraints the out of plane motion?

           

          first thing i might suggest is eliminating the bearings and making them fixed just to see what happens.

            • Re: Displacement visualization not matching scale
              Chris Michalski

              Jared -

               

              I ended up creating a duplicate of that model that ran fine.

              I tried both with and without soft springs and that didn't change it.

              I don't have gravity included (although I should have).

              There are 2 points on the laminate that are restricted in the plane (green dots at ends of laminate in 1st picture).

              There were never any errors or warnings during solving.

               

              The most bizarre part is that the stresses and forces are the same.  It is like it somehow simply got confused in the post processing portion and used a bogus picture.  For good or bad, as soon as I saw the duplicate was correct I deleted the original to avoid confusion so I can't investigate further.

               

              I had defined the displacements on the OD surface using the same split lines as for the bearings originally.  But in testing that variation again it does not recreate the unexpected graphics.  I'm not as concerned because the stress and displacement data are consistent, I'm willing to accept a graphics glitch.

               

              Thanks for the suggestions.