New hybrid algorithm for multi-objective structural optimization

Many engineering design problems can be formulated as constrained multiobjective optimization problems. The most popular method used to solve such problems is the weighted method; the major drawback of this method is that it doesn´t give a well distributed set. In this paper we propose to use the Normal Boundary Intersection approach (NBI) which is quite successful in producing an evenly distributed set of points in the Pareto set given an evenly distributed set of weights, it can be rigorously proved that this method is completely independent of the relative scales of the functions. To ensure the convergence to the global Pareto frontier, NBI approach must be combined with a global optimization method. In this work, we propose NBI-Simulated Annealing Simultaneous Perturbation method (NBI-SASP) as a new method for multiobjective optimization problems. A well known benchmark problem is used to examine the performance of the proposed global method (SASP) and good results were obtained. Also, an engineering multiobjective optimization problem of a welded beam design is used to examine the applicability of the NBI-SASP. Results show that our method has better search ability and it gives a well distributed global Pareto Front.