Probabilistic Double Linear Damage Accumulation Model and Time-dependent Reliability Analysis of Mechanical Structure

As the most common failure mode, fatigue fracture is a key factor affecting the usage life of mechanical structures and its system reliability. It is thus important to study the fatigue life and reliability of mechanical structures. However, the current life prediction and reliability analysis methods have not yet fully dealt with the fatigue failure process with complexity and randomness.Against this background, based on the fatigue damage accumulation theory, this study established a probabilistic double linear damage accumulation model, and carried out a time-varying reliability analysis. First, in view of the shortcoming that the traditional static reliability analysis method cannot reflect the time-varying characteristics of the load history, a probabilistic damage accumulation model with lognormal distribution is built based on the double linear fatigue damage accumulation theory. Then, based on the stress-strength interference theory, the static stress-strength interference model is extended to the dynamic time-varying reliability model of "damage accumulation-critical damage" by using equivalent treatment, and the reliability prediction is realized in the whole fatigue life cycle. Finally, the accuracy and effectiveness of the reliability analysis method proposed in this study is verified by numerical examples under constant amplitude and variable amplitude loading conditions respectively.