Fatigue life prediction for some metallic materials under constant amplitude multiaxial loading

• SSB model gives non-conservative life predictions under non-proportional loading.
• A critical plane-based fatigue life prediction model is proposed.
• The proposed model takes the non-proportional cyclic hardening into account.
• The effect of the non-zero mean stress can be accounted for by the modified model.
• The modified model gives the satisfactory fatigue life predictions.

Based on the critical plane approach, the Sun-Shang-Bao (SSB) model is analyzed and verified. It is discovered that SSB model cannot take the non-proportional cyclic hardening into account and gives non-conservative fatigue life predictions under the non-proportional loading. To solve this problem, a stress-correlated factor is introduced to describe the degree of the non-proportional cyclic hardening as well as the effect of the non-zero mean stress. The accuracy of the proposed method is systematically checked against the experimental data found in literature for 16 different materials under constant amplitude multiaxial loading paths.