Fatigue life-span prediction of electrically power assisted cycles frame in vibration test based on Grey Model
WEI Chao1，TONG Shuiguang1，FEI Zhongxiu2
1．Department of Energy Engineering，Zhejiang University，Hangzhou 310027，China；2．Institute of Chemical Machinery Engineering，Zhejiang University，Hangzhou 310027，China
Abstract：Utilizing JS-49 vehicle vibration test machine, 4 types of electrically power assisted pedal cycle frames were chosen to test their vibration durability, 10 specimens for each type. The finite element vibration analysis model was established to simulate the vibration test process for each type of the frame, then the Von Mises stress peak was extracted from the element where the crack occurred. Each type of frame corresponds to a stress level. The relationship of the fatigue stress and vibration cycles was considered as a Gray System. Gray System GM (1,1) model was built, then the differential equation of GM (1,1) was solved to obtain the critical parameters of the fatigue life-span prediction model. Error checking of the prediction model indicated that the average absolute relative error is 4.08%. The model could be used to guide the design of the products.
2013, Vol. 32 
