The Fatigue Life Prediction Based On The Improved Damage Model

Because of the existent of the empirical data in the calculation formula of the damage model, the calculation results generally deviate from the engineering practice when the mechanical fatigue life is calculated, which might result in potential safety risks. The hypothesis of virtual interval length is proposed based on the virtual load spectrum technology, and the Manson damage model is improved effectively. The research subject includes the virtual load spectrum, the virtual interval length division method of the original loading range, the improvements of the Manson model and its correction, the proof of convergence and the fatigue life prediction and solving method, etc. This study is derived from the Natural Science Foundation of China(NSFC51375154). The innovative points of the research are summarized follows:(1) The improvement for the fatigue damage model. The method of virtual interval length is proposed based on the virtual load spectrum technology. The study, according to the traditional Manson maxim, is also to virtually and equally divide the loading stress section of the virtual load spectrum and to build an improved fatigue damage model.(2) The research of the VILD–Manson model. In order to improve the accuracy of fatigue life prediction, some theoretical research is completed and the convergence is verified for the interval numerical value and the damage correction coefficient of the virtual load spectrum. The sine curve is used to modify the cycle damage value of virtual range to accurately simulate the fatigue damage process and to explore the influence of the interval numerical and the correction coefficient for fatigue damage calculation results.(3) The application case validation. In order to verify the prediction accuracy for the mechanical fatigue life of the VILD–Manson model, in this paper, fatigue test, the CAE simulation analysis, the rule of Miner, Manson model, and the improving Manson model are used to predict fatigue life of the sample and the life prediction results are been compared and certified.The VILD–Manson model is established based on the method of virtual interval length. The reliability of the VILD–Manson model in the design of mechanical fatigue is effectively improved by introducing the sine curve to modify the cycle damage value of virtual range, and it is beneficial for its application and popularization.