The fatigue crack growth (FCG) phenomenon generally exists in large mechanical structures. Due to the influences of varied kinds\nof randomfactors, the safety evaluation of structure in FCG is under great uncertainty. In this paper, based on the reliability theory,\nthe limit state equations of fracture failure and static strength failure were derived firstly, and the parameters in those equations were\nregarded as randomvariables that follow the normal distribution or log-normal distribution. According to the limit state equations,\nthe JC method (equivalent normalizing method) was used to calculate the reliability indexes under the different failure modes of\nstructure in every stress cycle. Based on the reliability indexes and correlation of the two failure modes, the joint failure probability\nwas obtained. In the end, a specific computation example was given, and the curve of joint failure probability in multiple failure\nmodes was used for comparison with the result of single failure mode.The results indicated that the reliability analysis based on\nmultiple failure modes was more reasonable, and the evaluation of reliability could be obtained in fatigue crack growth process.
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