Time-variant structural reliability analysis using bivariate diffusive crack growth models

Abstract

A method to estimate the reliability of structural components by which the time-variant properties of the structural resistance are taken into account is presented. Among the various deterioration mechanisms, which may cause this time variance, the present paper concentrates on the fatigue process, which is described by a bivariate diffusive surface crack growth model. The probability density function of the crack growth is derived by solving a Fokker-Planck-type equation. For updating the hazard rate following load applications, importance sampling simulation procedures are employed. The method is then applied to a piping problem. A sensitivity analysis shows the initial crack size as well as the loading stress amplitude to affect the reliability estimates most significantly.