...
A Failure Criterion value of 1 is always the objective of the optimisation. Four different types of Failure Criteria are available (von Mises Stress, FFF Thumb Rule, Directional Dependent Tsai-Hill or Tsai-Wu). More information regarding the Failure Criteria here.
The Safety Factor calculates the goal for the optimisation in regard to the material properties (material limits) for the chosen Failure Criterion. As a second option, a stress goal can directly be defined. This should be a value, that is fitting to the material and LBCs. The following two examples show how the goal for the optimisation is calculated:
...
In one optimisation several Events (load cases) can be considered. Each Event is calculated by itself and the stresses / Failure Criteria of all Events are enveloped and the highest value for each area is considered. For information regarding the Event Specific Safety Factor have a look here.
The Stress / Failure Criterion calculation is from an FE point of view an estimation. That’s why we recommend a FE-Reanalysis using Apex Structures/Nastran to verify the results regarding all boundary conditions. For the reanalysis the Nominal-Geometry should be chosen which will be used after manufacturing and post manufacturing processes. The Reanalysis can also take dynamic loading & other boundary conditions into consideration that are not considered in the design process.
...