A new method for estimating fatigue life of notched specimen

Fatigue life of engineering structure contains two parts: crack initiation life and crack propagation life. Fracture mechanics is adopted to estimate crack propagation life in the real engineering structures and has made some achievements. Actually, the existing study indicated that fatigue crack initiation is also an important period in the whole fatigue life. So, a new method to predict the whole fatigue life of notch components is proposed based on the theory of damage mechanics in this paper. The damage evolution equation of notch specimen under tension compression loading is obtained based on closed-form solution. The stress distributions of notch root are analyzed by finite element method. The whole fatigue life of notch specimen is estimated by the proposed method when stress concentration factor is different. It has been verified that the results calculated by proposed method is close to the experimental results and the model put forward in this paper is superior to Manson-Coffin Law. The result indicates that the proposed method is concise, effective and feasible for practical application.