Probabilistic fatigue cumulative damage model considering the randomness of load and material properties.

• Improvement of nonlinear fatigue cumulative models considering load sequence effect. • Probabilistic model to take into account the uncertainties of load and material character. • Incorporation of load exceedance variation of fatigue load spectrum. • Verification on 2297-T87 aluminum–lithium alloy under spectrum loading. A probabilistic fatigue cumulative damage model that can be applied to the fatigue life prediction of aluminum alloy under spectrum loading is proposed in this paper. The model is constructed by a novel nonlinear cumulative damage model, the P – S – N curve, and the probabilistic load–exceedance curve. It introduces the randomness of the loading process and fatigue resistance of the material to the deterministic model. In this model, it is derived that the cumulative damage under fleet spectrum loading exhibits an approximate lognormal distribution, and a method to calculate the distribution parameters is provided. Finally, the validity of the proposed probabilistic model is verified through fatigue tests on 2297-T87 aluminum–lithium alloy specimens under random loading, demonstrating its capability to capture the probabilistic nature of the fatigue behavior of aluminum alloy effectively. [ABSTRACT FROM AUTHOR]