| Subway development plays an important role in the construction of urban rail transit in China.Wheel polygon is a common problem of railway trains,which causes damage to track vehicle components.As a key component of railway vehicles,whether the fatigue life of bogie frame can meet the design requirements will affect the safety of train operation.Based on the measured dynamic stress data of the frame before and after the spinning wheel,this paper explores the influence of the wheel polygon on the fatigue life of the frame from two aspects of line test and simulation by establishing the rigid-flexible coupling model of the vehicle.This paper carries out the following work:(1)The dynamic stress data processing of the measured frame before and after the runner was completed,the stress spectrum was compiled and the change of equivalent stress amplitude before and after the runner was calculated.The results show that the decline rate of equivalent stress amplitude after the roller is related to the straight line and curve stations,and the decline rates are concentrated in 12.6%～17.5% and 37.5%～69.4%,respectively.(2)A complete rigid-flexible coupling vehicle system dynamics model was established.Input wheel polygon,American five spectrum,rail corrugation three excitation model.The bogie frame was flexible treated,and the modal of the frame before and after treatment was calculated and compared to verify the correctness of the flexible treatment.(3)The influence of wheel polygon on equivalent stress amplitude of frame under different working conditions was simulated and analyzed.When the running speed is66km/h,the curve radius is 350 m and the grinding frequency is 87.9Hz,the effect of wheel polygon on equivalent stress amplitude is the most obvious.(4)Based on the simulation of the stress frequency domain variation of the wheel polygon amplitude in 0.1mm～0.5mm,the stress frequency domain of the measured polygon amplitude of 0.5mm was reduced,and the stress-time history of different amplitudes was obtained by inverse Fourier transform.(5)The fatigue life of frame under different polygon amplitudes was calculated.The results show that the fatigue life decreases with the increase of wheel polygon amplitude.When the polygon amplitude is 0.5mm,the fatigue life of the frame is lower than the design life of 3.6 million km.(6)Based on fracture mechanics,the crack propagation life of the front and rear frame of the roller was calculated respectively.The crack propagation life of frame can be increased by reducing the influence of wheel polygon.The crack size extends from2.4mm to 5mm,and the crack propagation life under the worst wear condition and after the wheel turning condition is 26400 km and 4541200 km respectively.63 figures,34 tables,86 references. |
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