Structural optimization using response approximation and optimality criteria methods

Efficient optimum design of structures is achieved by approximating all the structural responses such as member forces, nodal displacements and frequencies. The approximate constraints that are bounds on element stresses, displacements and multiple frequencies are established by approximate responses, The non-critical constraints are omitted in each design cycle, Then an optimality criteria approach is used to solve the resulting approximate design problem. The results are employed as a starting point for the next cycle. The process is repeated until the design problem converges, The necessary derivatives of the functions under consideration are evaluated by a semi-analytical approach. The main objective of the present work is to reduce the number of required static and dynamic analyses as well as the overall computational cost of optimum design. Examples are offered to demonstrate the efficiency of the approach. (C) 1997 Elsevier Science Ltd.