Development of new critical plane model for assessment of fatigue life under multi-axial loading conditions

The present work is aimed at development of new critical plane model based on envelope of strain energy density as fatigue damage parameter. This model eliminates the use of hypotheses for evaluation of resultant shear. The fatigue life has been predicted and compared with test life for a large set of multi-axial test data available on SA 333 Gr. 6, 16MnR, S460N and 7075-T651 Al materials. Predicted fatigue life is in good agreement with test life. The predicted crack initiation orientations are also comparable with the measured angles. The shortcomings of existing models have been brought out.