车轮辐板开孔对车轮振动噪声辐射特性的影响

Effect of Web Hole on Vibration Noise Radiation Characteristics of Railway Wheel

以我国地铁列车常用车轮为例,利用有限元软件Ansys建立辐板无孔及分别开4,6和8个孔共4种车轮的三维有限元模型;在用Block Lanzos法进行车轮模态分析的基础上,采用模态叠加法对车轮振动频响进行分析;利用声学边界元软件LMS Virtual.Lab Acoustics建立车轮边界元模型,并将车轮表面振动频响结果作为速度边界条件,采用直接边界元法分析车轮振动噪声的辐射特性.结果表明：在车轮辐板上开孔有利于降低20～800Hz中低频段车轮振动噪声的辐射效率,而且辐板上开孔数越多,中低频车轮振动噪声的辐射效率也越低;但是,辐板上的开孔数越多,800～2 000Hz车轮振动噪声的辐射效率也随之增加;随着辐板开孔数的增加,250～450Hz车轮振动噪声的辐射功率随之降低;辐板开孔会改变1 000 Hz以上高频车轮振动噪声的辐射功率主频;车轮振动噪声的辐射声场并不是简单的单极子声场,辐板开孔对车轮振动噪声辐射声场的指向性有较大的影响.

Taking the common wheel of metro train in China as an example,3D finite element models of none web hole,4 web holes,6 web holes and 8 web holes of wheel were developed using FEM software ANSYS.On the basis of wheel modal analyses by Block Lanzos method,the frequency response of wheel vibration was analyzed using modal superposition method.A boundary element model of wheel was presented by boundary element method software LMS Virtual.Lab Acoustics,and then the frequency response result of wheel surface vibration was input as velocity boundary condition,the radiation characteristics of wheel vibration noise were analyzed by direct boundary element method.The numerical results indicate that wheel web hole is beneficial to reduce the radiation efficiency of wheel vibration noise in 20～800 Hz,and the more number of web hole,the lower radiation efficiency of wheel vibration noise in the low and middle frequency,but higher radiation efficiency of wheel vibration noise in 800～2000 Hz.Meantime,the more number of web hole,the lower radiation power of wheel vibration noise in 250～450 Hz.In high frequencies above 1 000 Hz,wheel web hole can change the main frequency of radiation power of wheel vibration noise.The acoustic radiation field of wheel vibration noise is not a simply monopole acoustic field,and wheel web hole has a significant influence on the directivity of acoustic radiation field of wheel vibration noise.