Research And Application On The Mechanical Behaviour Of Wheelset Equipped With Coupling Collar Based On FEA

The snap ring of wheelset influences the wheelset's behavior in many aspects, such as the static intensity, the fatigue strength, the dynamics performance and the minimum allowable stress. This may be a threat to the train's operation safety. This essay aims to the theory and experimental research of the train wheel which installs the snap rings. The main conclusions and the creative points are as following:(1) Takes a method of calculating with a snap rings directly to carry on imitation, calculation and analysis to the various research contents in this essay.(2) Put forward a method of calculation with the adoption extreme limit to carry on imitation, calculation and analysis to the various research contents in this essay.(3) The conclusion from the research on the assemble stress of the wheels of the Orbit vehicle shows that the maximum stress of the wheels under the maximum extreme limit when installed with snap rings is 271.7MPa. These stresses are much smaller than its yield stress, which is 420MPa. So it doesn't threaten the intensity of the wheels. However, the stress of the snap rings reaches its maximum value, which means the snap rings are extruded seriously. We should note from this that the remaining stress produced in the assemble period can't be neglected. We should try to reduce this stress.(4) The conclusion from the thermal analysis of the wheels installed the snap rings shows that under the minimum extreme limit, the surface temperature of the tire . is as high as 145.10℃, which has exceeded the critical temperature of the relaxation of the tire. This means that the tire has approached relaxation. In general, the wheel does not work under the minimum extreme limit, so the tire would not relax when it work under emergency brake. The thermal stress under the maximum temperature load and the maximum extreme limit is 236.1Mpa, which is smaller than that under single extreme assembling. This means that the thermal stress cause the heat expansion of the tire, and counterbalances a portion of the extreme limit. It should be avoided because it is dangerous although it would not threat the strength of the wheel.(5) For the first time to carry on mechanical capability analysis of wheel set equipped with coupling collar, and to assess the static strength, the fatigue strength. The maximum average stress in wheel set is 267MPa,.far below the bend limit 420MPa. The fatigue strength is 20.65MPa. Thus, we can know that both the static strength and the fatigue strength meet the moving demands.(6) The result of modal analysis of front wheel set and rear wheel set equipped with coupling collar indicates that, the maximum discrepancy of the first ten ranks inherence frequency is 12.7Hz, and the swing of them is almost the same as the shake model. Because the shake type of the first ten ranks reflect wheel's oscillation might existing in the moving, we can know whether the equipped coupling collar will affect wheel's dynamic capability or not. Under rail slot's impulsion load, although the existing of coupling collar has serious effect on the wheel's dynamic capability, it doesn't result in qualitative change.(7) By optimizing the thickness of the wheel hoop, we get the minimum allowable boundary of wheel hoop, which are 25mm and 26.03mm. Theoretically, 26mm is the minimum allowable boundary. Proving that the allowed boundary 38mm set by railway department, after equipping coupling collar on wheel set, still meets moving demands.(8) Simulate the fatigue life of the wheel set equipped with circlet by means of dummy project for the first time. The result shows that its fatigue life can reach 5.05 years. Moreover, according to the fatigue life simulation result, the weakness position of the wheel set is on the roll circle of the tire.(9) Select wheelset equipped coupling collar for the test, gather the data of the test with wireless instruments, and contrast the data with the result of finite element analysis. The discrepancy between the calculation and experimental results is about 8%, which proves this paper' s result is believable.