Study On Effect Of Wheel-rail Noise By Wheel Sound-proof Skirt For High-speed Train

In recent years,the rapid development of Chinese High-speed Railway has promoted the rapid growth of Chinese economy to a certain extent.While high-speed railways meet the requirements of higher speed grades,the impact and vibration between the wheels and rails will increase,and the noise level will rise rapidly.The problem of noise pollution caused by the development of high-speed railways will also become more severe.High-speed railway noise not only seriously interferes with people's normal work and rest,but also causes irreversible damage to their physical and mental health;in addition,the severe vibration generated by the train operation will cause the forced vibration of the buildings along the line and the reduction of the service life of related equipment.Therefore,it is of great significance to carry out the prediction and control of high-speed railway noise.Wheel-rail noise accounts for a large proportion of high-speed railway noise,and wheel noise is an important component of wheel-rail noise.Therefore,this dissertation systematically studies the shielding and control of the wheel-rail noise by the sound-proof skirt.Firstly,the wheel of high-speed trains is taken as the research object,based on the structural vibration theory and acoustic theory,the finite element method and boundary element method are used,the natural vibration characteristics,displacement admittance,acoustic radiation efficiency,and acoustic radiation directivity are used as evaluation indicators to analyze the vibration and noise radiation characteristics of wheels,and to provide a certain theoretical basis for the prediction and control of wheel-rail noise.Then use the wheel sound insulation skirt to control the wheel-rail noise.Based on the sound insulation theory of the structure,the statistical energy analysis method is used and the transmission loss is used as the evaluation index,the influence of the parameters of the sound-proof skirt on its noise reduction performance is systematically analyzed,and provide a theoretical reference for the optimal design and selection of the sound-proof skirt.Finally,the low trackside barrier is used as a supplementary measure for the sound-proof skirt to shield the lower half of the wheel to optimize the noise reduction performance of the sound insulation skirt,and the influence parameters of the low trackside barrier are designed to reduce noise radiation.Research indicates:Firstly,wheel natural vibration mainly has four types of modes: axial mode of 0 pitch diameter,axial mode of 1pitch diameter,radial mode and circumferential mode,and the modes are symmetrically distributed and the pitch diameter is the axis of symmetry;The axial vibration response is mainly the out-of-plane axial vibration of the tread and the spokes,and the radial vibration response is mainly the in-plane radial vibration of the spokes and the tread;the acoustic radiation efficiency of the wheel increases with the increase of frequency,and it is close to 1 in the high frequency band;the sound radiation directivity of the wheel shows symmetry due to the structural characteristics of the wheel,and the minimum value appears in the direction of the axle;in the mode with a large pitch diameter,the wheel has a strong directional jump and a smoother curve;the minimal value of wheel directivity in axial mode.Secondly,in the entire frequency band,changes in the structure and material of the sound-proof skirt will affect its transmission loss,especially in the high frequency band,and the wheel sound radiation efficiency is greater in this frequency band,which indicates that the sound-proof skirt can control the wheel noise radiation more specifically.Under the same conditions,the increased thickness of the end face of the sound-proof skirt is beneficial to effectively block the noise and reduce the economic cost;the Y-type sound-proof skirt has stronger noise reduction performance than the T-type sound-proof skirt,and both have an attenuation effect on the coincidence effect in the sound insulation process;the noise reduction performance of different materials is different in frequency sensitivity,so the sound-proof skirt can be designed with multiple materials and multiple layers.Thirdly,the low trackside barrier can effectively improve the noise reduction performance of the sound-proof skirt.Studying the influence of its structure and materials on the noise reduction performance,it is found that the transmission loss of the low trackside barrier is more sensitive to its thickness than to the highness;The larger the unit mass of the material used for the low trackside barrier,the better its sound insulation performance;top-sloping barrier can increase its transmission loss and reduce the coincidence trough depth.