Abstract: Based on the frequently-used engineering methods for fatigue life prediction and the performance measure approach, a reliable fatigue life model is built, and a set of methods for reliable life prediction and sensitivity analysis are proposed. By expressing fatigue life as the function of random variables, the reliable life prediction problem is converted into a spherical constraint optimization problem which can be solved using performance measure approach, and then the reliable life can be gotten directly. Moreover, the sensitivity factors for each random variable and deterministic variable can be calculated by using some intermediate variables in life prediction. The proposed method is demonstrated with a torsion shaft example. The results show that the proposed method has high efficiency and precision, and the different parameters have much different influences on reliable life.

Key words: ordnance science and technology, reliable life, fatigue life, probabilistic performance measure, sensitivity analysis