FATIGUE LIFE EVALUATION UNDER MULTIAXIAL RANDOM LOADINGS

The componentsof engineering structures are usually subjected to a complex loading. It is not always safe if a uniaxial fatiguemodel is used for fatigue design of structures under multiaxial loading. Fatigue lifeprediction under multiaxial random loading has been under study recently. Inthe course of the fatigue life prediction under multiaxial random loading, cyclecounting is first to be considered. The rainflow counting method can be used to countthe cycles in the multiaxial loading. Cumulative fatigue damage analysis plays a keyrole in the life prediction of the components and the structures subjected to loadhistories. Since the linear damage rule was proposed, many damage models have beendeveloped. The fatigue damage due to random loadings can be determined bydifferent damage models.But none of them is universally accepted. The applicability of each model varies fromcase to case. The linear damage rule is still dominantly used in design, in spiteof its major shortcomings. The damage accumulation in two loading levels and modes,and the relationship between the damage and the physical mechanism are reviewed inthis paper. The fatigue life prediction models under multiaxial random loadingare reviewed in detail and the applicability of these models are discussed. Somesuggestions are made for future research.