Verification and Evaluation of Critical Plane-based Multiaxial Fatigue Life Prediction Models

The multiaxial fatigue lives predicted by six critical models were compared by using five kinds of materials. It is found that for the same material significantly different results may be obtained by the different models. Furthermore, for different materials the predictions from the same model may be lower or higher than the test results. The validity of life prediction of different models not only depends on the validity of fatigue damage parameters for the prediction models but also the rationality of the expression of the prediction models. Besides, the validity of the models is also related to the cracking mode of the materials. Generally speaking, the Fatemi-Socie model can give reasonable fatigue life predictions for shear-typed cracking materials. Based on the verification results, the applicability of the considered fatigue life prediction models is overviewed. Then it is pointed out that the applicable conditions of conven-tional critical plane models need to be further studied. And the physical meaning of the coefficients in the damage parameters and the relationship among the coefficients, the stress-strain state and the material characteristics need to be further studied as well.