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For each scenario and iteration a failure criterion is calculated and based on this value the design is formed. Which failure criterion can be used depends on the material properties, manufacturing method and the optimisation intention.
Von Mises Stress*
The equivalent von Mises Stress is the default Failure Criterion. It can be used for all material properties (Isotropic, 3D Transversely Isotropic and 3D Orthotropic). The Stress Goal is calculated with the chosen Safety Factor and the tension strength in axis direction (build direction) of the entered material. For directional dependent stress limits, the von Mises Stress is not suitable and one of the following Failure Criteria should be used.
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Directional Dependency (Tsai-Hill)*
The directional dependent Tsai-Hill Failure Criterion allows to set-up different Tension Strength for the build direction (axis) and the In-plane directions as well as the Shear Strength. The FFF Thumb Rule is based on it, in contrast to it the Shear Strength isn’t calculated automatically based on the Thumb Rule.
Directional Dependency (Tsai-Wu)*
With the directional dependent Tsai-Wu Failure Criterion the difference between Tension and Compression Strength can be considered besides the directional dependency.
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