A DYNAMIC PENALTY-FUNCTION METHOD FOR THE SOLUTION OF STRUCTURAL OPTIMIZATION PROBLEMS

This paper presents an adaptation of an existing dynamic trajectory me thod for unconstrained minimization to handle constrained optimization problems. This is done by the application of a dynamic penalty parame ter procedure to allow for the constraints. The method is applied to s tructural optimization problems that involve the determination of mini mum weight structures of trusses and frames, subject to stress, displa cement, and frequency constraints, under various prescribed load condi tions. Because structural problems, in general, require detailed finit e-element analyses to evaluate the constraint functions, the direct ap plication of the trajectory method, requiring updated information at e ach step along the path, would be expensive. This problem is overcome by the successive application of the trajectory method to approximate quadratic subproblems that can be solved economically. The comprehensi ve new approach is called the DYNAMIC-Q method The method is successfu lly applied to a number of truss and frame problems and is found to be both reliable and easy to use.