Modeling and Verification for Time Dependent Counting Method
Fan Wenliang1,2 Wei Gangyi1 Li Zhengliang1,2
1 School of Civil Engineering, Chongqing University, Chongqing, China, 400045; 2 Key Laboratory of New Technology for Construction of Cities in Mountain Area(Chongqing University), Ministry of Education, Chongqing, China 400045
In order to obtain the fatigue damage at different moments, the counting operation must start from the initial time to the object time of the stress time history by traditional counting methods, in other word, the former time history, which is already counted, should be counted again for the fatigue damage at latter moments. To overcome the shortcoming mentioned above, the authors proposed the time dependent counting method, which perform the counting of increment stress history by referring to the principle of increment method in structural dynamical analysis. By combining the counting result and residue of last moment with the ones of subsequent increment history, and taking simple and reasonable operation, the total counting result of the current time history is acquired easily. Obviously, the proposed method is more efficient than traditional method because of avoiding repetitive counting of former history, which is also illustrated approximately by simple theoretical analysis. Finally, the precision and rationality is verified by several numerical cases through the comparison of results of the proposed method with the ones of traditional rainflow counting methods.