The method for structural reliability analysis considering the first three moments as interval variables

Abstract

In the traditional structural reliability method, the first three statistical moments of random variable are used to describe its uncertainty. But in practical engineering, due to the lack of statistical data, it is difficult to obtain the statistical moments of some random variables, and the failure probability is no longer the determined value. To solve this problem, this paper treats the uncertain first three moments as interval variables, and proposes the method to compute the interval range of failure probability with the uncertain first three moments measured as interval variables. This method uses the simplified third moment normal transformation model to map the limit state surface from the original space to the standard normal space. By distinguishing the statistical moment interval values corresponding to the upper and lower boundaries of the limit state strip in the normal space, limit state functions corresponding to the upper and lower boundaries of the limit state strip are established with the system reliability, and method of moments is used to calculate the interval of failure probability. In this paper, it is the first time to assess the structural reliability analysis considering the first three moments as interval variables, and the accuracy and efficiency of this method in structural reliability analysis are proved by examples.