Optimum Structural Design with Dynamic Constraints

Dynamic response quantities, treated parametrically in time, are included in the problem for the first time. The method is made efficient by the use of the following approximation concepts: (1)Design variable linking; (2)time parametric constraint deletion; and (3)use of the first-order Taylor series expansions of the dynamic response functions with respect to the design variables. It is found that the feasible design space in an optimum structural design problem in the dynamic response regime is usually disjoint. The Davidon-Fletcher-Powell algorithm is used for the unconstrained minimizations. To successfully implement the exterior penalty function with approximate constraints, dummy boundaries and a new concept of move limits are introduced. It is found that the sinusoidal contributions in the relation between design variables and dynamic response functions can cause infeasible minima of the exterior penalty function.