Life prediction method based on short crack propagation considering additional damage under axial-torsional non-proportional loading

•A multiaxial total life prediction method based on short crack growth is proposed.•The additional damage from non-proportional loading path is characterized.•Effect of shear stress on crack growth under tensile/compressive stress is considered.•The proposed method is verified by two materials under multiaxial loading. A total life prediction method based on short crack propagation considering additional damage from non-proportional loading is proposed under multiaxial fatigue loading. Firstly, a new calculation method of equivalent stress range is proposed to consider the effect of shear stress on crack propagation under tensile or compressive stress, then it is further modified to consider the additional damage. Combined with Paris formula and crack closure correction, a total life prediction method is proposed. The life results were used to verify the proposed method for two materials, which showed that most errors are within a factor of 3.