Reliability Research On The Fatigue Capability Of Wangon Coupler Yoke

With the development of heavy haul and speed increased of freight car,the impactof collision and traction force of vehicle increase rapidly.the fatigue life of the part ofcoupler and draft gear drops obviously,which brings the seriously hidden defect of thesafety of railway transport.so it is very necessary to research the fatigue performanceof the typical coupler yoke systematically.According to the data shows, nearly all the crank position of the coupler yoke lie inthe the coupler yoke rear fillet and body of joint (hereinafter referred to as jiont).By lotsof finite element calculation in the rear end face which is exerted the balanced load,wefind that the fatigue weak position of the coupler yoke is not the real crack positionaccording to the field. Referred to some related data, when the coupler is enduring theimpacting or traction load,the face that is vertical with the coupler yoke rear end facewill produce a small and inclined upward force(the upward component force hereinafterreferred to as upward force and the slanted ascender angle hereinafter referred to asupward angle) and deviate from the center of coupler yoke rear end face(hereinafterreferred to as eccentricity).The thesis makes the analysis of the theory force and thesimulated line force by the improved No.17(hereinafter referred to as the improvedNo.17), and then by lots of finite element calculation and fatigue life estimate,we findthat upward force and eccentricity are the main reason which makes the coupler yokerear fillet and body of joint (hereinafter referred to as joint)produce the crack,and withthe increment of upward angle and the eccentricity distance,the fatigue life dropsrapidly,which explains the reason of the produced crack, finally,the specificimprovement measures and advice for improving the fatigue life of coupler yoke is putforward. According to the AAR load spectrum and the Datong-Qinhuangdong loadspectrum of the2,0000ton heavy haul vehicle,the thesis makes use of the nominalstress method,the local stress-strain method,the fracture mechanics method to estimatethe nominal stress life,the crack initiation life and the crack propagation life from twoaspects of the theory force and the simulated line force respectively,and compares thenominal stress life with the total of the crack initiation life and the crack propagationlife from two aspects of the theory force and the simulated line force respectively,thusproving the validity of the nominal stress life.Finally, According to a array of the fatigue life of experiment datas of various types of coupler yoke, the thesis makes use of the Weibull distribution to analyse thereliability of the fatigue performance of the coupler yoke.