Multiaxial fatigue life prediction for metals by means of an improved strain energy density-based critical plane criterion

Abstract

In the present paper, a new generalized strain energy density-based life prediction model was proposed by analyzing the drawbacks of the commonly-used fatigue life prediction criteria. In the proposed model, the critical plane was defined as the maximum shear strain energy density plane with the larger normal strain energy density. A weight index was introduced in this model to take into account the different influences of the normal and shear strain energy components on fatigue life. The maximum normal stress and shear mean stress were both introduced to consider the effects of mean stress. Besides, the maximum normal stress can also be used to account for the reduction of fatigue life under non-proportional loading. The step-by-step procedures were presented to determine the orientation of the critical plane as well as the damage parameters contained in the proposed model. The accuracy and reliability of the proposed model were systematically checked by using about 280 test data through testing 8 kinds of materials under both proportional and non-proportional loadings with zero/non-zero mean stresses. Comparisons with three commonly-used life prediction models showed that the proposed model has highest life prediction accuracy and reliability.