| With the rapid development of high-speed railway,the vibration and noise problem has attracted much attention.Wheel-rail noise is an important source of railway noise.With the further increase of train running speed,the proportion of wheel noise in wheel-rail noise which is an important source of railway noise increases gradually.Since the damping of the all-steel wheel is relatively small,the wheel modal damping ratio of a specific frequency can be effectively increased by installing the tuned mass dampers(TMD)device to reduce the wheel noise.At present,there are few studies on the noise reduction characteristics and mechanism of high-speed rail TMD,although the TMD device is widely used,and its noise reduction characteristics are not analyzed when considering the wheel-rail interaction at high-speed.In this dissertation,the research objects are based on high-speed train wheel.In order to study the noise reduction characteristics,mechanism and optimization of high-speed wheel TMD device,the following research work was carried out:(1)A review of the studies all around the world on wheel-rail noise theory and its application,development status of dynamic vibration-absorbing theory and application status of wheel TMD products,in which the direction of wheel TMD research direction was carried out.(2)The control theory based on multi-modal tuned mass dampers according to the wheel TMD structure was discussed The multiple number of TMD structural parameters of highspeed wheel were designed by developing multiple parallel TMD mechanical models,and the wheel vibration was controlled by using the TMD with multi-modality based on equivalent modal mass theory.Based on this method,the optimal MTMD parameters for the cantilever beam structure and the disc structure were realized respectively.The optimal parameter calculation process for the wheel MTMD was summarized.(3)The modal parameters of the reference wheel and the TMD wheel in free state were obtained through the wheel vibration noise test conducted in the semi-anechoic chamber,and the influence of the TMD device on the vibration radiation of the wheel was tested and analyzed.The finite element models of the reference wheel and the TMD wheel were established,and the vibration and noise reduction mechanism of the wheel TMD were understood by analyzing the difference between the mode shape and the tuning frequency difference.The influence parameters of the wheel TMD noise reduction effect were clarified.(4)The influence of the number of wheel TMD tuning frequencies and the number of dampers on the vibration radiation of the wheel was investigated,and the number of suitable TMD installations of the wheel was determined with the optimal parameters of the wheel TMD.The optimal analysis of the number and thickness of the damping layer of the TMD structure was carried out to determine the parameter optimization range based on the optimal damping theory.The thicknesses of the rigid layer and the layup were optimized based on the optimal homology condition,and a linear regression model is established for the modal frequency of the TMD structure.Then,the structural frequency of the wheel MTMD was optimized using a multi-objective optimization method.The wheel MTMD structure optimization scheme achieved the optimization goal of tuning multiple modal frequencies.(5)The vibration and noise reduction performance of the reference wheel,TMD wheel and the TMD optimized wheel under wheel-rail roughness excitation were analyzed and predicted by using the wheel-rail noise prediction model.The noise reduction characteristics of the wheel and the total noise of the wheel and rail were studied and analyzed at different speeds when the train was installed with the TMD device.The structure parameters of the tuned mass damper were further optimized and the noise reduction effect of the simulated wheel-rail noise was predicted after changing the wheel boundary conditions with combing with the linear regression model of wheel MTMD. |
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