Keyword type: step
With *OBJECTIVE one can define the objective function for which a feasible direction shall be computed in a *FEASIBLE DIRECTION step. The feasible direction is basically the sensitivity of a design response function defined as objective, possibly corrected by design responses defined as constraints and/or geometric constraints. Right now, the calculation of a feasible direction can only be done for TYPE=COORDINATE design variables. The objective function can be any design response function defined in a previous *SENSITIVITY step. It is referred to by using its name given on the *DESIGN RESPONSE line.
There is one optional parameter TARGET. If TARGET=MIN (= default) the sensivity is calculated for a minization of the objective, if TARGET=MAX for a maximization. The difference comes into play when determining which constraints are active. Exactly one *OBJECTIVE keyword is required in a *FEASIBLE DIRECTION step. This keyword has to be followed by exactly one design response name.
Example: *OBJECTIVE DR1
defines the design response with name DR1 as the objective.
Example files: opt1, opt3.