Abstract: By means of randomizing Miner's linear cumulative damage rule and generalizing the Stage Fatigue Life Branch-and-Bound Method, the Global Fatigue Life Branch-and-Bound Method is suggested for enumerating the significant fatigue failure modes and computing fatigue failure probability of a large scale structural system under given loads and service life. Using flexible control bounds, the problem of losing significant failure modes is completely solved in the case of one-order and multi-order searching depth and a good efficiency in convergence is obtained, about which a rigorous theoretic proof is provided. The feasibility and validity of this method for enumerating significant fatigue failure modes and evaluating total reliability of a structural sysem are also verified by practical compulation and analyzing of some type of classical structures.

Key words: reliabiliy latigne, damage, IUC, Brunch-and-Bound Method