Improved line sampling method for structural reliability with high dimensionality and small failure probability

For reliability analysis of implicit limit state function, an improved line sampling method is presented on the basis of sample simulation in the failure region. Markov chain is employed to simulate the samples located at the failure region, and the important direction of line sampling is obtained from these simulated samples. On the other hand, the simulated samples can be used as the samples for line sampling to evaluate the failure probability of implicit limit state function. Since the important direction is searched accurately and robustly by simulated samples in the failure region, the efficiency of line sampling is improved obviously. Furthermore, the computation cost of line sampling is reduced also, because the simulated samples can be used for line sampling. A few examples demonstrate the rationality and efficiency of the improved line sampling method.