A Stable Method for Time-dependent Reliability Analysis

Abstract

The problem of time-dependent reliability arises in engineering practice due to the degradation of structural material properties over time and the involvement of time-dependent loads. For time-dependent reliability analysis (TRA), outcrossing rate method is one of the main methods with the key issue of solving the outcrossing rate. Recently, EPHI2 method has been proposed as an advanced outcrossing rate method that can efficiently computes outcrossing rate by means of a two-component parallel system model. However, EPHI2 method will lead to unstable results, due to its sensitivity to time intervals. Therefore, a new method called EPHI2+ is proposed in this paper, which has a more stable expression for the outcrossing rate. To show the corresponding improvement of EPHI2+ method, the comparison of the outcrossing rate results obtained by EPHI2 and EPHI2+ methods was shown. The application of EPHI2+ method for TRA is investigated by two numerical examples and it is found that EPHI2+ method can be applied effectively with sufficient stability and accuracy.