An envelope-function-based algorithm for time-dependent reliability analysis of structures with hybrid uncertainties

This paper proposes a novel envelope-function-based algorithm for time-dependent reliability analysis considering random and interval uncertainties. First, the envelope function of the bound of the limit-state function is approximated with assistance of the first-order reliability method, thereby transforming time-dependent reliability problem into a time-independent one. Here, the Kriging modeling method is utilized to construct the expansion point determination function for reducing the most probable point search, which significantly accelerates the expansion point determination in constructing the envelope function. After the envelope function is found, the time-dependent reliability in terms of random and interval uncertainties is efficiently calculated by a multivariate Gaussian integral. Finally, five case studies are used to demonstrate the effectiveness of the proposed algorithm. The results indicate it can provide accurate and efficient time-dependent reliability analysis for structures where the random and interval uncertainties coexist.