Stopping rule of multi-start local search for structural optimization

Abstract

Stopping rule for multi-start local search is investigated for application to structural optimization problems with moderately large number of local optima. The size of attractor of an unknown local optimal solution is estimated using the information of already obtained solutions. A stopping rule is defined using the likelihood of obtaining the specific set of local optimal solutions. This way, characteristics of the specific optimization problem is successfully incorporated. The proposed rule is first verified using the mathematical problems in comparison with the existing rule utilizing the estimated ratio of the total size of attractors to the size of feasible domain. The rule is next applied to an optimization problem of a plane frame under constraints on inter-story drift angle and stress against static loads. Characteristics of the distribution of attractors of optimal solutions are also investigated.