3 Replies Latest reply on Aug 29, 2018 12:37 PM by James Riddell

    fix an edge in one direction

    Sean Johnson

      I've done some searching, and haven't found the answer to what should be a simple question:

       

      lets say I have a beam I'm modeling.  I have a symmetric situation, so I cut the beam in half and put a roller/slider fixture at the cut end.

       

      The other end I want to be supported against vertical deflection, but not against deflection along the axis.  I'm going to put a distributed load on the beam.

       

      How in the heck do I support that edge?  Every time I try to put a constraint on, Simulate wants to fix it completely

        • Re: fix an edge in one direction
          Alex Burnett

          This sounds like a good use for an advanced fixture.  Fix the flat face selected with respect to its normal only. As long as you have the rest of the model fully constrained, it sounds like this will give you what you are looking for.

           

          Edit: The other two toggle options for the translations will affect the other two axis directions which typically line up with the global coordinate system.

            • Re: fix an edge in one direction
              Sean Johnson

              Alex, you're right about that.  My confusion was in that the other two directions aren't blank; they "0", but it's greyed out.  If I leave those alone though, and complete the fixity, it only shows a green arrow in that one direction.  Guess I should have done that...

              • Re: fix an edge in one direction
                James Riddell

                Be very careful, check the reaction forces on the surface after running to verify that you end up with very small orthogonal forces - and they will be there - when you apply this (essentially) roller-slider constraint.

                 

                Over constraint is, IMHO, the single most severe error an analyst can make.  You'll be blindsided when it breaks.