PurposeA large number of data have proved that under the same von Mises equivalent strain condition, the fatigue life under multiaxial non-proportional loading is often much lower than the life under multiaxial proportional loading. This is mainly due to the influence of the non-proportional loading path and the additional hardening effect, which lead to a sharp decrease in life.Design/methodology/approachThe modulus attenuation effect is used to modify the static hardening coefficient, and the predicted value obtained is closer to the additional hardening coefficient obtained from the experiment. A fatigue life model can consider non-proportional paths, and additional hardening effects are proposed. And the model uses multiaxial fatigue test data to verify the validity and adaptability of the new model. The life prediction accuracy and material application range are satisfactory.FindingsBecause loading path and additional hardening of the material affect fatigue life, a new multiaxis fatigue life model based on the critical plane approach is proposed. And introducing a non-proportional additional damage coefficient, the joint influence of the load path and the additional hardening can be considered. The model's life prediction accuracy and material applicability were verified with multiaxial fatigue test data of eight materials and nine loads compared with the prediction accuracy of the Kandil–Brown–Miller (KBM) model and Fatemi–Socie (FS) model.Originality/valueThe physical meaning of the new model is clear, convenient for practical engineering applications.

To meet the different functional requirements of the components, irregularities and geometric discontinuities occur in the structural design of the components. These geometrical discontinuities lead to local stress concentrations, which inevitably introduce notch effects. The unyielding internal material still supports the high‐stress area on the plane due to the supporting effect of the notch. This effect can lead to inaccurate prediction of fatigue life. So, the notch support factor and strain were used as damage parameters to modify the life prediction model of the notched specimens in this research. And an improved critical plane method is applied in selecting damaged planes. It considers the damage at the notch before loading and uses dynamic weights to measure the effect of the maximum stress plane on the damaged plane. The model was validated using TC4 and GH4169 notch data and compared with other models, and the revised model has higher accuracy. The damaged plane and damage parameters to modify the fatigue life of the notched specimen make more physical sense and are more consistent with the fatigue failure mechanism.