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Symmetry Plans

By using the (symx), (symxdir), and (symx2) parameters in GridHoriz command (and analogous paramaters in the GridVert and GridDepth commands), you can create one or two symmetry planes along each axes. For one symmetry plane, the plane is located at x = (symx). If (symxdir) = -1 (or is omitted), the plane is at the minimum edge for the coordinate; if (symxdir) = +1, the plane is at the maximum edge. To create two symmetry planes, create the first one using (symx) and (symxdir) and then use (symx2) for the location of the other plane. The second plane will be on the opposite side as the first plane (e.g., maximum edge if first was minimum or minimum edge is first was maximum). Plane locations are entered in length units.

Symmetry planes should used whenever the planes exist in a model (e.g., when modeling half the specimen). These planes automatically insert zero velocity boundary conditions over the entire plane, and thus are the easiest way to create a plane of boundary conditions. Furthermore, the velocity conditions are special reflective conditions that give improved results by making use of symmetry. You can track total reaction force on symmetry planes using global archiving of reaction forces along with symmetry plane IDs.

Symmetry planes are essential whenever multimaterial contact occurs at the plane. The use of a symmetry plane is used to help in finding multimaterial normals that are crucial to accurate calculations.

More details on symmetry planes can be found on the OUSPDocs wiki.