Page 176 - Finite Element Modeling and Simulations with ANSYS Workbench

5

Modeling and Solution Techniques

5.1 Introduction
In this chapter, we discuss several techniques in the modeling and solution options of
using the FEM. Applying these techniques can greatly improve the efficiencies and accura-
cies of the FEA.

5.2 Symmetry
Symmetry feature of a structure is the first thing one should look into and explore in
the FE modeling and analysis. The model size can be cut almost in half and the solu-
tion efficiencies can be improved by several times. A structure possesses symmetry if its
components are arranged in a periodic or reflective manner. Types of symmetries are
(Figure 5.1):

• Reflective (mirror, bilateral) symmetry
• Axisymmetry
• Rotational (cyclic) symmetry
• Translational symmetry
• Others (or combinations of the above)

In the FEM, symmetry properties can be applied to
• Reduce the size of the problems and thus save CPU time, disk space, postprocess-
ing efforts, and so on
• Simplify the modeling task
• Check the FEM results (make sure the results are symmetrical if the geometry and
loading of the structure are symmetrical)

Symmetry properties of a structure should be fully exploited and retained in the FE
model to ensure the efficiency and quality of FE solutions.

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