Size (Parameter) Optimization

The properties of structural elements such as shell thickness, beam cross-sectional properties, spring stiffness, and mass are modified to solve the optimization problem.

OptiStruct has the capability of performing size optimization simultaneously with the other types of optimization.

Defining size variables in OptiStruct is similar to other size optimization codes. Each size variable is defined using a DESVAR Bulk Data Entry. If a discrete design variable is desired, a DDVAL Bulk Data Entry needs to be referenced for the design variable values. The DESVAR cards are related to size properties in the model using a DVPREL1 or DVPREL2 Bulk Data Entry. Each DVPREL Bulk Data Entry must reference at least one DESVAR Bulk Data Entry to be active during the optimization. HyperWorks includes a pre-processor called HyperMesh that can be used to set up any number of size variables for the properties.

The following responses (see Responses for a description) are currently available as the objective or as constraint functions:

Mass	Volume	Center of Gravity
Moment of Inertia	Static Compliance	Static Displacement
Natural Frequency	Buckling Factor	Static Stress, Strain, Forces
Static Composite Stress, Strain, Failure Index	Frequency Response Displacement, Velocity, Acceleration	Frequency Response Stress, Strain, Forces
Weighted Compliance	Weighted Frequency	Combined Compliance Index
Function	Temperature