Reliability Estimation of Fatigue Damaged Structure using Various Probability Theories

Abstract

The methodologies to calculate failure probability and to estimate the reliability of fatigue loaded structures are developed. The applicability of the methodologies is evaluated with the help of the fatigue crack growth models suggested by Paris and Walker. The probability theories such as the FORM (first order reliability method), the SORM (second order reliability method) and the MCS (Monte Carlo simulation) are utilized. It is found that the failure probability decreases with the increase of the design fatigue life, and the decrease of the initial edge crack size, the stress range, and the stress ratio. Furthermore, according to the sensitivity analysis of random variables, it is found that the slope of Paris equation affects the failure probability dominantly among other random variables in the Paris and the Walker models.