Creating Valid Sections for Cyclic Symmetry

The cyclic symmetry constraint is appropriate for simulations of models where the geometry, restraints, and loading conditions are repeated in a cyclical pattern with reference to a central axis.

To set up your model for applying cyclic symmetry restraints, you create a cut (or an assembly cut feature) to produce a section of the model that can be repeated in a cyclical pattern about a central axis of revolution. A valid cut section produces a complete part, when it is repeated with an equal spacing circular pattern feature, and there are no gaps or interferences between the sections. You cannot apply a cyclic symmetry restraint to an invalid section.

Example: Seven-blade impeller

You cut the model to produce an appropriate section that is one seventh of the original model.
impeller.png impeller_sketch.png

As the geometry, restraints, and loads are repeated cyclically about the central axis of the impeller, the cyclic symmetry restraint is appropriate for a simulation performed on a representative cut section of the impeller.

The sketch of the extruded cut has two equal radius arcs intersecting the center axis and the outer edge of the model. The position of the two arcs relative to the model and the arc radius are adjusted so that the cut fully encompasses a section of the model equal to one seventh of the original model. The angle between points on each arc located at the same distance from the center axis is 51.43 degrees, which is evenly divisible into 360 degrees (360 / 7).

impeller_cut_section.png impeller_circular_symmetry.png
Extruding the sketch creates a cut section that is valid for cyclic symmetry. Apply cyclic symmetry restraints to the cut faces. Applying cyclic symmetry restraints to a valid section creates a rendering of the whole model.
After you run the analysis, you can display results on the full model. In the PropertyManager of the desired result quantity, under Advanced Options, select Display symmetric results. Results are repeated cyclically about the defined axis of revolution.