OST: 5020 3D Bracket Model using the Freeshape Method
In this tutorial you will perform a shape optimization on a solid bracket model using the Free Shape optimization method. The objective of this optimization is to reduce the stress by changing the geometry of the bracket model.
 Objective
 Minimize (Max von Mises Stress).
 Constraints
 No Constraints.
 Design Variables
 Grids move normal to the surface.
Launch HyperMesh and Set the OptiStruct User Profile
Open the Model
Set Up the Optimization
Create Freeshape Design Variables
Create Optimization Responses
 From the Analysis page, click optimization.
 Click Responses.

Create a static stress response.
 In the response= field, enter Stress.
 Set the response type to static stress.
 Using the props selector, select stress_faces.
 Set the response selector to von mises.
 Under von mises, select both surfaces.
 Click create.
 Click return to go back to the Optimization panel.
Define the Objective Function

Create an objective reference.

Define the objective.
 Click the objective panel.
 Select minmax.
 Using the dobjrefs= selector, select MAX_STR.
 Click create.
 Click return to go back to the Optimization panel.
Define the SHAPE Card
 From the Analysis page, click the control cards panel.
 In the Card Image dialog, click SHAPE.
 Set FORMAT to H3D.
 Set TYPE to ALL.
 Set OPTION to ALL.
 Click return twice to go back to the main menu.
Run the Optimization
View the Results
View the Shape Results
View a Contour Plot of the Stress
Set Up a New Freeshape Optimization Simulation with Moving Constraints
In practice, however, there will be some sort of constraints imposed upon the movement of grids due to manufacturability. For this tutorial model, thickness must be unchanged to avoid any interference with other parts.
In this step you will define constraints on DSHAPE grids such that the thickness of design space will remain unchanged.
The constraints on the curved part will be created using a local rectangular coordinate system (the other constraints on the flat part do not need a local coordinate system). Therefore, a local rectangular coordinate system (zaxis will point to normal to DSHAPE surface) needs to be created first.