Improved Model for Computing Time-Variant Reliability Based on Outcrossing Rate

Time-variant reliability problems have been studied widely by scholars recently, and they usually are solved on the basis of the outcrossing rate. The common method to calculate the outcrossing rate involves a static parallel system reliability problem of two components, and sequentially the time-variant reliability can be computed by Rice's formula. This formula, however, is not ideal because of its assumptions of Poisson distribution and independence for outcrossings, and thus a significant error may be generated. Therefore, the formula for computing time-variant reliability was rederived and modified in this paper. Time-variant reliability first was derived based on the failure rate, and then the approximate relationship between the outcrossing rate and failure rate was provided. Consequently, Rice's formula for calculating time-variant reliability based on outcrossing rate can be modified from the perspective of failure rate, which can remove the drawbacks of the assumptions of Rice's formula. Several examples were provided to validate the efficiency and accuracy of the proposed method. (c) 2020 American Society of Civil Engineers.