DYNAMIC RELIABILITY COMPUTATION FOR NON-LINEAR STRUCTURES BASED ON SUBSET SIMULATION METHOD

Subset simulation method is a new method for dynamic reliability calculations. Based on the original method, the proposal probability density function is selected in this paper, and the intermediate response threshold values are chosen adaptively. The conditional probabilities are evaluated by modified Metropolis algorithm. The detailed numbers of samples for calculating conditional probabilities are determined. Then calculation procedures for subset simulation method are presented. The efficiency of subset simulation method is demonstrated by calculating the first excursion probabilities of two examples. One is a Duffing system with single degree-of- freedom, the other is a three degree-of-freedom structure with three lines restoring model. The two structures are both subjected to stationary white noise excitation. For the Duffing system, when determining the samples that fall in the failure domains, responses of the non-linear structure need to be calculated, and iterative numerical step-by-step integration method is adopted. Results show that the proposed method can be applied in the dynamic reliability calculation for non-linear structures. It is accurate and efficient especially for computing small probabilities.