Reliability of Fatigue Damaged Structure Using FORM, SORM and Fatigue Model

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 applied minimum stress, and the decrease of initial edge crack size, applied maximum stress and slope of Paris equation. Furthermore, according to the sensitivity analysis of random variables, it is found that the slope of Pairs equation affects the failure probability dominantly among other random variables in the Paris and the Walker models.