2 Replies Latest reply on Oct 31, 2017 10:52 AM by Alfons Schure

    rotation fixture

    Alfons Schure

      Simulation Question: How can I fix a rotation of a plane, without fixing any translations.

       

      Goal:

      A hollow cylinder static simulation. The faces of the hollow cylinder (or a part of a cone to be more precise) need to be fixed parallel, while a force is pushing on the side of the cylinder. I want to study the deformation of this cylinder.

       

      What I did: Modeled a quart of the cylinder and put a roller slider fixture on all the sides. At one of the sides that cuts the cylinder a force is applied. This almost is what I want, but it prevents the cylinder from getting slightly longer, which caused unwanted stresses and behavior. Therefore I want one of the sliding fixtures to only keep the plane straight, but allows movement orthogonal to this plane. In the figure I've attached to this post: The sliding fixture at the left (or right) must allow axial movement, but keep the plane straight and still allowing the round shape to become an oval shape because of the force.cylinderquestion.png

        • Re: rotation fixture
          Keith Frankie

          Interesting problem.  I think I follow what you're trying to do.

           

          I modeled a big cube on the far wall.  I restrained it to move along the axis of the cone.  I made it rigid, which means it can't deform.  Making it rigid also makes SW mesh the exterior as a shell, which means its not very computationally expensive.

           

          I put a spring between the cube and the cone face.  I made the 'normal stiffness' super high, so the cone face can't move toward or away from the cube.  The tangential stiffness is 0, so it can slide (translate) freely.

           

           

           

          I used a displacement plot to help verify the constraints are working.  The plot is for UX, the direction parallel to the axis of the cone.  I set the min and max values to bracket the values shown on the cone face edge.  The uniform color indicates they are all moving the same distance, hence they are moving together.  They are non-0, indicating the face is indeed translating.

           

           

           

          I think you're making a quarter section of the cone; you might use the symmetric fixture instead of 'on plane'.  They are equivalent, but with the symmetric fixture you can mirror results.