A New Model for Predicting Crack Initiation Life in Thin Walled Tubes under Multiaxial Proportional Loading

The theory of fracture mechanics is unable to estimate crack initiation life, but the theory of damage mechanics can do it well. The application of critical plane method in multiaxial fatigue has made certain progress. According to the law of thermodynamics, a new damage model is proposed in this paper to predict the crack initiation life under multiaxial proportional loading condition based on damage mechanics and critical plane method. The maximum shear strain amplitude and the normal strain on the maximum shear strain plane are the components of this model. Finally, the crack initiation life is predicted with the proposed model, which is damage mechanics-critical plane method. The predicted results of using the new model comply with the experimental results.