A multiaxial fatigue criterion for various metallic materials under proportional and nonproportional loading

Proportional and nonproportional tension–torsion fatigue tests were conducted on LY12CZ aluminum alloy. Two types of tubular specimens were used, one is smooth and the other is notched. The experimental data are analyzed. A new critical plane criterion including the strain and stress parameters is proposed. The capability of fatigue life prediction for the proposed fatigue damage model is checked against the experimental data of LY12CZ aluminum alloy and two other metals under proportional and nonproportional loading, and the predicted results are compared with results from common multiaxial fatigue model. It is demonstrated that the proposed criterion gives better satisfactory results for all the three checked materials.