Abstract:Reliability-based design optimization (RBDO) involves two sub-optimization procedures for the overall optimization and iterative reliability analysis, and its computational effort is prohibitive. In this paper, the sphere design space (SDS) method is developed to improve the efficiency of probabilistic optimization. The SDS method rebuilds the reliability analysis model, in which the search area is easily described and the most probable points (MPPs) can be obtained from the extreme points accurately. Also, the optimization and reliability analysis processes are conducted simultaneously. The computation capability of SDS is demonstrated using two examples which are widely used to test RBDO methods. The comparison results show that SDS method has the similar accuracy as existing methods, and it is also very efficient.