FATIGUE LIFE EVALUATION UNDER MULTIAXIAL RANDOM LOADINGS

The components of engineering structures are usually subjected to a complex loading. It is not always safe if a uniaxial fatigue model is used for fatigue design of structures under multiaxial loading. Fatigue life prediction under multiaxial random loading has been under study recently. In the course of the fatigue life prediction raider multiaxial random loading, cycle counting is first to be considered. The rainflow counting method can be used to count the cycles in the multiaxial loading. Cumulative fatigue damage analysis plays a key role in the life prediction of the components and the structures subjected to load histories. Since the linear damage rule was proposed, many damage models have been developed. The fatigue damage due to random loadings can be determined by different damage models. But none of them is universally accepted. The applicability of each model varies from case to case. The linear damage rule is still dominantly used in design, in spite of its major shortcomings. The damage accumulation in two loading levels and modes, and the relationship between the damage and the physical mechanism are reviewed in this paper. The fatigue life prediction models under multiaxial random loading are reviewed in detail and the applicability of these models are discussed. Some suggestions are made for future research.