Research Progress on Fatigue Behavior and Life Prediction under Multiaxial Loading for Metals

Multiaxial fatigue damage behavior and life prediction is related to the service safety of metal structures under complex loading condition, which has received great attention in the field of science and engineering. The general process of fatigue testing and fatigue behavior research under multiaxial low-cycle and high-cycle fatigue are summarized. The influence of multiaxial nonproportional loading on fatigue behavior of low-cycle and high-cycle fatigue is emphatically discussed. The effect of nonproportional loading on low-cycle fatigue hardening behavior and fatigue life of materials is different due to the loading path, loading load and material type. The effect of nonproportional loading on fatigue behavior of low-cycle and high-cycle fatigue and damage mechanism is also different. Uniaxial constitutive relation can be extended to the field of multiaxial fatigue by introducing nonproportional factor, correcting cyclic strength coefficient or equating the strain of multiaxial loading to uniaxial strain. The multiaxial fatigue life prediction models based on stress, strain, energy, the critical plane and critical plane strain energy density methods are reviewed. Some multiaxial fatigue life prediction approaches which contain energy term in fatigue damage parameters have been applied to a wide range of multiaxial low-cycle and high-cycle fatigue life. The fatigue life of notched parts can be predicted based on the multiaxial damage parameters combined with the local stress-strain method, stress gradient method, stress field intensity method and critical distance method. © 2021 Journal of Mechanical Engineering.