Fatigue test and service performance evaluation of high-speed train hanging equipment bolts

The high-speed train hanging equipment may extend maintenance cycle, prompting an urgent need for bolt service performance evaluation. In this paper, the hanging bolts of the hanging equipment of high-speed trains are taken as the research object, and accelerated fatigue tests of the hanging bolts under five alternating loads are designed and carried out. The SN curves of the bolts under axial loads are obtained with the Goodman modified equation and double logarithmic linear regression analysis, which provides a basis for acquiring the cycle life under different real vehicle loads. A tracking test system for real trains was established, and vibration acceleration data of four types of hanging equipment were obtained when the high-speed train was running on the Beijing-Shanghai high speed railway. An averaging method based on supervised classification was proposed, and the average daily acceleration load spectrum of different hanging equipment with cycle characteristics of 1.2 million km was constructed to provide data support for service mileage evaluation. A service mileage evaluation model of the hanging bolts based on the fatigue life model, Miner's rule and train dispatching rules was proposed. Moreover, the service mileage evaluation of four types of hanging bolt equipment was completed to provide an important reference for the formulation of a bolt repair system for the hanging bolt equipment of high-speed trains.