A single-loop strategy for time-variant system reliability analysis under multiple failure modes

This paper proposes a single-loop strategy for time-variant system reliability analysis by combining multiple response Gaussian process (MRGP) and Kriging model. Firstly, a new strategy is provided to decouple the double-loop strategy of extreme-value-based time-variant system reliability analysis, where the extreme value response in the double-loop strategy is approximated by the best value in the initial points to avoid the inner-loop extremal optimization. Then, the extreme value response surface is directly built based on the approximated extreme value using the MRGP model. Meanwhile, a Kriging model based on initial points is also proposed to search a new sample point. Furthermore, in order to update the initial sample points and improve the accuracy of the proposed strategy, three learning functions (U-function, EFF-function and H-function) and expected improvement (EI) function are combined to select a new point that resides as close to the extreme value response surface as possible. Finally, several examples are presented to demonstrate the effectiveness of the proposed strategy. (C) 2020 Elsevier Ltd. All rights reserved.