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CHAPTER 11: OBJECTIVES AND CONSTRAINTS
11.4 Bounds on the constraint functions
Upper and lower bounds may be placed on the constraint functions.
Command file syntax:
Lower bound constraint constraint_name value <-10+30>
Upper bound constraint constraint_name value <-10+30>
Example:
Lower bound constraint ’Stress’ 1.e-6
Upper bound constraint ’Stress’ 20.2
Remark:
1. A flag can be set to identify specific constraint bounds to define a reasonable design space. For this
purpose, the move environment must be specified (See Section 9.5).
11.5 Minimizing the maximum response or violation*
Refer to Section 2.15.1 for the theory regarding strict and slack constraints. To specify hard (strict) or soft
(slack) constraints, the following syntax is used:
Command file syntax:
strict strictness_factor <1>
slack
Each command functions as an environment. Therefore all lower bound constraint or upper
bound constraint commands which appear after a strict/slack command will be classified as
strict or slack.
In the following example, the first two constraints are slack while the last three are strict. The purpose of the
formulation is to compromise only on the knee forces if a feasible design cannot be found.
Example:
$ This formulation minimizes the average knee force but
$ constrains the forces to 6500.
$ If a feasible design is not available, the maximum violation
$ will be minimized.
$
$ Objective:
$----------composite ’Knee_Forces’ type weighted
composite ’Knee_Forces’ response ’Left_Knee_Force’ 0.5
composite ’Knee_Forces’ response ’Right_Knee_Force’ 0.5
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