| Thermal load of tread break and wheel-rail force will increase with the axle loadincreasing, which may lead to thermo-mechanical fatigue damage and endanger traffic safety.Therefore, the thermal mechanical coupling phenomenon was analyzed to solve the variousconditions at a certain moment wheel stress state and complete the static strength and fatiguestrength in this thesis.Static strength of axle was checked based on EN13103,JIS E4501and TB/T2705-2010criterion at first. The results show that, the static strength of the axle at wheel seat, fillettransition region are less than the allowable stress so it can meet the requirements.The equivalent stress of three conditions was calculated which contain linear, curve andaisle bifurcation. The result is that the minimum is196MPa and the maximum is255MPa soit can meet the requirements of static strength. It checked the fatigue strength of the wheelbased on Haigh-Goodman curve, when consider to the results, all data are located on theenvelope line which mean the fatigue strength can meet the requirements.Secondly, the wheel interference fit and contact pressure was analyzed based on finiteelement method, maximum amount of interference and minimum interference of wheelpressing force. The results show that, the von-mises and amount of interference and pressureare positively correlated. The calculation of contact pressure was given considering thechanges of pressure in different axle load.It calculated temperature distribution and thermal stress of new wheel and worn to thelimit wheel under eight conditions and analyzed the influence of environment temperature orramp（length or slope） to the brake temperature. The results show that, the effects of theenvironment temperature on the brake temperature is merely10℃;the maximum von-mises inlong ramp circumstance is144MPa, however, the maximum von-mises in emergency brakingcondition is545MPa,which are far less than the allowable stress. Therefore, the wheel canmeet the requirements in separate thermal load. Curve fitting to parameter the temperaturewas utilized in order to study the effect on wheels or on railway when the train come to abrake and solve some phenomenon in this brake step.Finally, wheel strength was analyzed the when thermal load and mechanical action in thesame time, the results show that, the stress is larger than mechanical or thermal load actionseparate. At the same time, we come to a conclusion that the influence of thermal load is larger than mechanical does. Haigh-Goodman curve was utilized the to check fatigue strengthof worn out wheel in curve line when come to a urgent brake, which may come to a failure. |
