Explicit Model of Outcrossing Rate for Time-Variant Reliability

Abstract

The usual approach to time-variant reliability problems is PHI2 method, which defines the outcrossing rate as a two-component parallel system problem and calculates it through a two-dimensional numerical integration. To improve the computational efficiency, an explicit model of outcrossing rate is proposed in this study, which is referred to as EPHI2. Based on the proposed explicit model, EPHI2 method avoids the numerical integration required in PHI2 method. Comparison between the outcrossing rates obtained by PHI2 and EPHI2 methods was conducted, and EPHI2 method was proved to have enough accuracy for calculating outcrossing rates. The application of EPHI2 method for time-variant reliability analysis was investigated through three numerical examples. It is found that the proposed EPHI2 method is more efficient than PHI2 method in time-variant reliability analysis, with the results nearly the same.