Current design methodologies for LCF/HCF of aero engine components are based on traditional uniaxial stress/strain methods like strain-life (ε-N), stress-life (S-N) and Goodman / Haigh diagram approaches, often applied with a wide safe factors to account for uncertainties in the understanding of multiaxial loading and other effects. With constantly striving to improve the performance and life of gas turbine engines, there is a need to increase accuracy of life prediction and reduce maintenance cost. Some multiaxial fatigue methods like Manson-McKnight, Sines, Smith-Watson-Topper etc. were developed to convert the multiaxial stresses into an equivalent uniaxial stress. This conversion simply provides the treatment of both the mean stress, the stress amplitude and directions. However, critical locations in engine components often experience significant multiaxial non-proportional loading conditions, such as blades and LP/HP shafts are subjected to HCF loading associated with mixed bending and torsional vibration modes. In this paper, the use of a new multiaxial fatigue life model was explored in the prediction of multiaxial fatigue behavior in aeronautic materials and structural steel. This new life model is based on the multiaxial S-N curve and an improved multiaxial high-cycle fatigue criterion which validated before by authors. The applied range of this new multiaxial fatigue life model were also compared with other models. Several groups of solid and hollow specimens with different ductile materials were conducted and evaluated under multiaxial loading cases. The predictions based on the proposed model give a better statistical result than other models.

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