General Information

This chapter gives an overview of the combination of design responses.

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DRESP

For the combined terms the following table shows the allowed combinations between the strategy and the items OBJ_FUNC and CONSTRAINT with C for controller and S for sensitivity-based optimization. The * marks those for which only weighted sums (included differences) are allowed.

TOPO

SHAPE

BEAD

SIZING

OBJ_FUNC

S*

C, S

S*

CONSTRAINT

S*

S

S*

Creating response combinations like relative values, differences or mean values requires operations on a number of previously extracted design responses.

  • For sensitivity-based topology optimization, only weighted sums are admitted in objective function and constraint definitions.
  • For controller-based shape optimization, a large variety of other operators are admissible.

All operators are available to create new responses for monitoring of optimization results. Weighted sums operate on one to 10 variables defined by the item VARIABLE. All other operators combine (operate on) one to four variables whereas the order of the variables is significant.

DRESP
 ID_NAME = .....
 DEF_TYPE = OPER
 VAR_OPER = SUB  or  SUB_ABS or ...
 VAR_A = .....
 VAR_B = .....
END_

and

DRESP
 ID_NAME = .....
 DEF_TYPE = OPER
 VAR_OPER = COMBINE
 VARIABLE = ....., .....
 VARIABLE = ....., .....
    ....................
END_
Important:

  • Only Design responses from the same load cases are allowed to be combined.
  • Maximal 5000 Design responses are allowed.
  • For sensitivity-based topology optimization design responses can only be combined using DEF_TYPE = OPER if they refer to the same load cases. Combination of design responses with OPER cannot be done for two separate load cases. Nevertheless for shape optimization design responses for different load cases might be combined.