Development Of Fatigue Life Prediction Toolbox Based On Fracture Mechanics

The theoretical basis of fatigue life prediction system is fracture mechanics in this article. The application tool is a GUI interface of MATLAB. Through the relevant literature, it shows that there are so many theories about fatigue life prediction based on fracture mechanics theory. But the research is little about fatigue life prediction toolbox. Some companies have developed certain fatigue life prediction system according to their own needs. But its versatility is rather poor. And given the principle of confidentiality, users can not use some software. In order to solve this problem, this paper chooses MATLAB as a development platform. The aim is to develop the fatigue life prediction system on basis of fracture mechanics theory. On the other hand, fatigue mechanics theory describes the real process of crack propagation. The result of fatigue life prediction is accurate. And some engineering problems can be solved. Therefore this research has important theoretical significance and application value.This paper mainly studies life estimation problems and damage tolerance design. First of all, the function of the system has been analyzed. And the types of function module have been determined. Second, the curve fitting of fatigue crack growth rate has been analyzed. And four data processing methods have been used to realize the curve fitting. And six crack growth rate models have been chosen, such as the formula of Paris, the formula of Walker, the formula of Forman and so on. Third, the prediction of fatigue crack propagation life under constant amplitude loading has been researched. And this module achieves two parts:the acquisition of the stress intensity factor and fatigue crack propagation life estimations. Fourth, residual life, residual intensity and check intervals have been analyzed based on damage tolerance theory. Fifth, an equivalent method of variable amplitude loading has been studied. And the fatigue life prediction method under variable amplitude loading has been determined. Finally, the interface of the system has been completed on the basis of MATLAB.The system is one part of fatigue life prediction toolbox based on MATLAB. It can run independently in MATLAB. It has a good expansion of portability and versatility. And the system provides a powerful tool for the majority of fatigue research workers and engineering and technical applications personals.