Macro-micro Cross-scale Numerical Simulation Of Fatigue Failure Process

The experimental data of fatigue life of materials are often very discrete,which indicates that the microstructure of materials has an important influence on their fatigue failure behaviors.Therefore,it is necessary to develop a new method for numerical simulation of a fatigue failure processe from micro-to macro-scale.In addition,the new approach can take the microscopic effects into account.A crack model with the restraining stress zone is analytically solved by using the complex function mehtod.Then,this model is applied to the numerical simulations of fatigue failure processes for the plate and rod specimens.The main work is as follows:(1)The engineering background and research significance of fatigue damage are briefly introduced.The development history of the fatigue analysis theories is reviewed.The existing fatigue analysis approaches are addressed.(2)The crack model with a restraining stress zone is analyzed and solved by the complex function method.(3)The fatigue failure process of TB5 titanium alloy plate specimens is numerically simulated by using this crack model.The results are compared with the experimental results.It is seen that the new approach can take the micro-factors of a material into account.Thus,the reason of the scatter of the fatigue data can be explained.(4)The fatigue failure processes of TA19 titanium alloy specimens at different temperatures are numerically simulated.The influence of material micro-factors on the fatigue failure process is analyzed and discussed.