An Efficient Method for Time-Variant Reliability including Finite Element Analysis

Time-variant reliability evaluation including finite element (FE) analysis requires relatively large computational efforts, as FE analysis is time-consuming and the number of calls to FE analysis in time-variant reliability analysis (TRA) cycle is generally large. In this study, a moment-based PHI2 (MPHI2) method is proposed for evaluating time-variant reliability including FE analysis, based on the statistical moments of the limit state function at successive time instants. Instead of conducting FE analysis repeatedly in TRA cycle, MPHI2 method separates FE analysis from the cycle by representing the associated components in the limit state function as a random variable/process and estimating its statistical characteristics before the TRA cycle. After the separation, time-variant reliability can be evaluated based on the assumed random variable/process with no need to conduct FE analysis, which may significantly reduce the number of calls to the FE analysis and thus improve the computational efficiency. Three numerical and practical examples are presented to illustrate the application and efficiency of the proposed MPHI2 method.