抄録
In the many practical structural design problems, the design variable is large-scale and the objective function has multipul peak. On the problems, a two steps search technique is effective. That is, the first step is to search the quasi-optimal topological solution in the large domain by the heuristic techniques as the GA, and the second step is to search the optimum solution as the size problem of the solution by the mathematical techniques. By the technique, a truss and a continuum structural problems which have multipul peak are analyzed as the phase and size determination problem. From the results, it is obvious that the technique is effective to the large-scale structure problems.
