Experimental Research And Application Of The Longitudinal Loading Spectrum Of The Coupler Of 20000-ton Heavy-haul Train On Datong-Qinhuangdao Railway

ABSTRACT:It is a milestone of our Chinese railway transportation that the 20000-ton Heavy-haul Train on Datong-Qinhuangdao Railway has been put into service in march 2006.Yet the greater longitudinal forces caused by heavy load result in a worse working condition of the coupler and draft gear system. A reliable coupler's loading spectrum is needed to do the fatigue design in order to ensure the safe operation, however, because of the complexity and particularity we can't use the existing abroad spectrum totally to complete fatigue analysis. So, it is necessary to compile a proper load spectrum which is applicable to our 20000-ton Heavy-haul Train.In this paper, the relationship between longitudinal load and time of the twenty couplers of the 20000-ton Heavy-haul Train has been achieved through site surveys, as well as got the distribution of the longitudinal load, the 2-D loading spectrum were achieved, and then, based on these spectrum,the fatigue analysis of coupler knuckle is completed. During the site surveys, through grouping ten force measuring couplers with the fore and the last ten cars of the train respectively and using the auto measuring instruments, my group get the random load on these couplers.In order to eliminate the influence of disturbance, some data preprocessing, such as filtering,smoothing and so on, are used to have a pretreatment of the original data, after that, on one hand, through analyzing the achieved load-time course of coupler, I investigate the generation and variation of couplers'longitudinal forces and research the mechanism of how and where the biggest longitudinal force of the train takes place on different work conditions, on the other hand, with rain flow counting method, the 2-D loading spectrum of these twenty couplers is gained. Based on these spectrums, and given it is necessary for getting a accurate result to take the local plasticity into consideration, I choose the steady-state method of the local stress-strain approach to calculate the fatigue life of these twenty couplers, and the Miner rule is involved in the accumulation of fatigue damage, and at the same time, in order to remove the specification of result caused by the fixed sequence of couplers, I compile a mixed coupler spectrum, and get a universal result of the coupler knuckle's fatigue life.