Study On The Noise Characteristics Of Metro Resilient Wheel Under Wheel/Rail Impact

There are a large number of impact-type excitations on subway lines,and the impact noise caused seriously harms the physical and mental health of drivers and passengers.By adding rubber structure between the rim and the wheel core,the resilient wheel can effectively reduce the interaction force between the wheel and rail,so as to reduce the vibration and noise level between the wheel and the rail.However,the resilient wheel is only used in trams in China,and has not been applied in subway lines.Therefore,analyzing the vibro-acoustic characteristics of subway resilient wheels under wheel/rail impact excitation,so as to promote the application of resilient wheel,and control the impact noise of subway lines.This thesis aims to analyze the noise characteristics of resilient wheel under impact-type disturbances.Using implicit-explicit finite element method,a three-dimensional(3D)transient rolling contact model is established.The interaction force between the wheel and the rail is solved in the time domain.The finite element method and boundary element method are used to establish wheel impact noise prediction model,and the calculation results of the rolling contact model are used to complete the calculation of wheel impact noise.The main research contents of the thesis are as follows:(1)Using the implicit-explicit finite element method,three-dimensional transient wheelrail rolling contact model of resilient wheels and rigid wheels are established.The actual wheel-rail geometry,the nonlinearity of wheel-rail contact and the superelasticity of the rubber material in the resilient wheel are all taken into account.The transient contact solution when the wheel rolls over a smooth rail is calculated,which verifies the accuracy of the model in simulating the wheel-rail transient contact behavior.(2)On the basis of the established rolling contact model,by modifying the coordinates of the relevant nodes on the rail surface,the model can consider the effect of rail welded joints and rail corrugation.The time-domain results of wheel-rail normal force at the rail welded joint and rail corrugated are calculated.Analyzing the influence of welded joint and corrugated geometry on the vibration characteristics of the two wheels,and the vibration reduction effect of resilient wheels.The research results show that rail welded joints and short-wavelength rail corrugation will aggravate the wheel-rail dynamic response.The resilient wheel can effectively reduce the amplitude and maximum value of the interaction force,which are caused by the excitation of these two types of irregularities.Under long-wavelength corrugated excitation conditions,the wheel-rail force amplitude of the resilient wheel is not significantly reduced.(3)Established the wheel’s harmonic response analysis model.By applying radial unit force excitation at the nominal contact point of the wheel,the frequency response of the wheel is analyzed by the modal superposition method,and the wheel vibration response results is obtained.Based on the direct boundary element method,sound radiation prediction models of resilient wheels and rigid wheels are established.Using the wheel-rail interaction force calculated by the rolling contact model as the excitation input,the influence of rail welded joints and rail corrugation geometry on the sound radiation level of wheels is studied,and the noise reduction mechanism of resilient wheels is analyzed.The research results show that the wave depth of the welded joint has a greater impact on the impact noise of the wheel.With the increase of the wave depth of the welded joint,the level of wheel noise shows an increasing trend.The noise levels of resilient wheels and rigid wheels increase in different degrees at the corrugation passing frequency.Resilient wheels can effectively reduce the level of wheel radiation noise at the rail welded joints and rail corrugated parts.