Fatigue life prediction for titanium plate considering impact defect

Based on the theory of continuum damage mechanics, fatigue life prediction for Ti-1023 titanium plate with impact pit is studied. By analyzing the combined effect of impact damage and fatigue damage, considering the coupling effect of stress field and damage field, the fatigue life of titanium plate with impact pit is predicted. Firstly, on the basis of the continuum kinematics theory, the nonlinear dynamic finite element analysis software is used to simulate the process of impact damage, and the residual stress field and plastic strain field around impact pit are also obtained. Secondly, the initial damage field is calculated according to the plastic damage model, which will be input as the initial conditions of the subsequent fatigue calculation. Then, the multiaxial fatigue damage model of Chaudonneret is adopted and the damage mechanics-finite element numerical method is proposed to conduct the damage evolution calculation. Finally, this method is used to predict the fatigue life of titanium plate with impact pit and the corresponding fatigue tests are conducted for validation. The results show that the prediction lives are in accordance with test data. The research provides a feasible method for fatigue life prediction of metal component with impacted damage in engineering practice.