4 Replies Latest reply on Oct 2, 2008 5:01 PM by Vince Adams

    Symmetry question

    Jim Wisén
      Can I use the symmetry constraint as shown in the picture to make a simulation instead of adding twice as many components to build another "module" that looks exactly the same?

      Does symmetry work on all parts (shell and solids), restraints, loads etc?


      Best regards
      Jim Wisén
        • Symmetry question
          Steven Dinsdale
          If the second half is identical (mirror image) then you can use symmetry.

          Do note that you have applied a "fixed" restraint to the end, not symmetry, which is far different.

          -Steven
            • Symmetry question
              Vince Adams
              Additonally, symmetry is valid only when the loads and restraints on both halves are identical as well.

              The Symmetry restraint "shortcut" only works for solid faces. To model symmetry for a shell edge or beam joint, choose a "Use Reference Geometry" restraint type. The Direction Plane must be parallel to the symmetry cut plane. Restrain to "0" the translations normal to this plane and the other two Rotations.

              Unlike the "Symmetry" restraint, you must create a completely new restraint for each symmetry cut, or direction you are using (remembering that you can only use 3 symmetry planes.) The shell edges or beam joints chosen for a symmetry restraint in this manner MUST be co-planar. If any are out of plane, your results may get skewed.

              -- Vince
                • Symmetry question
                  Jim Wisén
                  Thanks for your great answer!

                  As seen in the picture above the symmetry is on a shell face (not shell edge), is that valid? The results seams ok. Does this define the symmetry cut plane and include both shells and solids?


                  //Jim Wisén
                    • Symmetry question
                      Vince Adams
                      A "Symmetry Restraint" using the shortcut can be applied to a shell face. Remember that by using this, you are telling the Simulation that the actual shell is twice the thickness used since you are 'virtually' slicing the plate down its mid-surface. This may or may not matter depending on the response in that area.

                      Symmetry works for all element types but you need to be careful when mving past solids.

                      Vince