DISCRETE VARIABLE OPTIMIZATION OF PLATE STRUCTURES USING DUAL METHODS

This study presents an efficient method for optimum design of plate an d shell structures, when the design variables are continuous or discre te. Both sizing and shape design variables are considered. First the s tructural responses, such as element forces, are approximated in terms of some intermediate variables. By substituting these approximate rel ations into the original design problem, an explicit nonlinear approxi mate design task with high quality approximation is achieved. This pro blem with continuous variables can be solved very efficiently by means of numerical optimization techniques, the results of which are then u sed for discrete variable optimization. Now, the approximate problem i s converted into a sequence of second level approximation problems of separable form, each of which is solved by a dual strategy with discre te design variables. The approach is efficient in terms of the number of required structural analyses, as well as the overall computational cost of optimization. Examples are offered and compared with other met hods to demonstrate the features of the proposed method.