Defining design variables – Geometry Optimization

Design variables define those aspects of your design that you allow the optimization to modify for the redesign.

Depending on your model and solution type, you can define the following values as design variables:

• Beam section properties

• Shell element properties

• Feature dimensions

• Sketch dimensions

• Expressions

Updates to CAE polygon geometry when design variables are based on CAD features

If you define a design variable for a CAD feature dimension, be aware that when you make changes to the CAE model’s polygon geometry—such as splitting, stitching, or merging bodies, faces, or edges—the CAE polygon geometry and the CAD model may become out of sync. As a result, design variables that are based on CAD features may no longer be associative to the CAE model. If this is the case, when the  optimization updates these design variables, the changes may not be propagated to the polygon geometry, and the mesh may not be updated.

When a body’s edges and faces do not have an exact, one-to-one correspondence between the CAD model and the CAE polygon body, the following warning appears.

Geometry optimization model check warnings: Polygon geometry does not have one-to-one conformity to the original cad geometry. Optimization updates to CAD feature design variables may result in partial update of the CAE model.

Using expressions as design variables

When you create a design variable using an expression that was created outside of the Simulation file, the software creates an interpart expression that the design variable references. The interpart expression automatically locks the original expression. After you solve the optimization, if you decide to reset the model by solving again, you must first delete the design variable to unlock the expression, and then recreate the design variable.

How do I

Create the geometry optimization

Create a weight or volume objective

Create a frequency objective

Create an objective from a result measure

Create a weight or volume constraint

Define a frequency design constraint

Create a constraint based on a result measure

Define design variables for the geometry optimization

Solve the geometry optimization

Learn more

Geometry optimization

Geometry Optimization workflow

Types of geometry optimization

Design objective – Geometry Optimization

Defining design constraints – Geometry Optimization

Part files modified by Geometry Optimization

Analyzing optimization results

Update an expression with the result from a specific iteration

Look up more details

Geometry optimization parameters

Quick links

Exporting result quantities as named expressions

Command reference

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Defining design variables – Geometry Optimization, Simcenter 3D 2021.1 Series

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