Setting up Sensitivity based optimization

The creation of a sensitivity based optimization setup is shown using the example of a connection rod.

Context:


Design nodes	Initial stress distribution

In order to create a runnable Tosca setup for a sensitivity based shape optimization, draw attention to the following parts of the parameter file:

Use the following command to define the target:
Important: For the objective function definition the only allowed TARGETs are MIN and MAX. It is NOT allowed to use MINMAX as target.
```
OBJ_FUNC
  ID_NAME = OBJ_FUNC_1_OBJ_FUNC_ITEM_1
  TARGET = MIN
  ...
END_
    
```
The next thing to take care about is setting the box constraints for the design variables: Use the CHECK_GROW and CHECK_SHRINK commands.
Note: The design nodes should not grow or shrink by more than 5 units.
```
DVCON_SHAPE
  ID_NAME = DVCON_SHAPE_GROW_SHRINK
  ND_GROUP = DESIGN_NODES
  CHECK_GROW = 5
  CHECK_SHRINK = 5
END_
    
```

The most important change must be made to the OPTIMIZE command: change the STRATEGY to SHAPE_SENS:

OPTIMIZE
  ID_NAME = OPTIMIZE_1_SHAPE_OPTIMIZATION_CONTROLLER
  ...
  STRATEGY = SHAPE_SENS
END_


Result stress distribution	Result nodal distribution	Convergence plot, red: Volume constraint, blue: objective function