方向重点サンプリング・シミュレーション法に基づく構造システムの信頼性評価法の研究

抄録

This paper provides an improved directional simulation method to estimate the structural failure probability. A method is proposed to construct a directional importance sampling density, which generates more samples of direction vectors in the direction where the limit state surfaces are closer to the origin. The proposed method is composed of two-stage procedures. In the first stage, a preliminary simulation is executed to search the distances from the origin to the limit state surfaces in the directions normal to finite element meshes allocated on the unit sphere. A directional importance sampling density is constructed so as to be proportional to the upper probability of chi-square distribution corresponding to each distance. In the second stage, a directional importance sampling simulation is executed to estimate the structural failure probability.
All samples are effectively generated to estimate the structural failure probability and the proposed method is effective for the reliability assessment of the structural systems. Numerical examples are provided to show the validity of the proposed method.