Vibro-acoustics Characteristics Analysis Of Rotating Annular Plates And Dynamic Vibration Absorbers Applied On Railway Wheels

In recent years,high-speed rotating machineries such as high-speed railway wheels,gears,turbine rotors and etc.have become more and more important in the national economy.However,these machines always subject to various external loads such as mechanical,aerodynamic,temperature field and even magnetic field,which will produce noise caused by lateral vibration.Strong noise will seriously affect people’s normal production,life and ride comfort of vehicles.However,the existing research on the rotating annular plate components mainly focuses on their stability,the research on its vibration and noise is limited.Therefore,the research on the vibration and noise of rotating annular plate is of great significance for the design of such components.As an efficient vibration and noise suppression structure,dynamic vibration absorber s(DVAs)is widely used in the vibration and noise control of beams,plates,shells and etc.However,the frequency of rotating annular plates changes with the change of its rotating speed and has multi frequencies characteristics.Thus,the design method of DVAs with multi-frequency vibration and noise reduction performance applied to such components needs further study.Consequently,this paper takes the rotating annular plate as the research object,and studies the inherent characteristics,noise characteristics and noise control of multi frequency DVAs under different parameters,and the specific research contents are as follows:Based on the classical thin plate theory,the free vibration control equation of the rotating annular plate in the rotating coordinate system is derived using Hamilton principle.The equation is solved using Galerkin method,and the correctness of the theoretical derivation is verified by the form of experiment and simulation.Firstly,the variation of the dynamic frequencies of the rotating annular plate with its rotating speed is analyzed.Subsequently,the sensitivity of the rotating speed to the parameters of the annular plate,such as geometry,material,boundary conditions,is analyzed.It is found that with the decrease of the thickness diameter ratio and elastic modulus of the annular plate,the influence of rotating speed on its dynamic frequencies is more significant.At the same time,it is found that only when the rotating speed of the annular plate reaches a certain value,the rotating speed on the dynamic frequency will be more obvious.Based on the free vibration equation of the rotating annular plate,the differential equation of the transverse vibration of the rotating annular plate subjected to a transverse point force is established.The equation is solved by the Galerkin method,and the transverse displacement and velocity of the rotating annular plate under the transverse point excitation are obtained.Based on radiation element method,using Rayleigh integral,the radiated sound power and radiation efficiency of the rotating annular plate which excited by transverse point load are derived.The correctness of the theory is verified by both experiment and simulation.Based on the established theoretical model,the effects of rotating speed,geometry,material,boundary conditions and other parameters on the radiated sound power and radiation efficiency are analyzed.It is found that with the increase of the rotating speed of the annular plate,the radiated sound power tends to move to higher frequency,while with the decrease of the thickness diameter ratio and the elastic modulus of the annular plate,the radiated sound power tends to move to the lower frequency,and the distribution is more intensive in the same frequency band,while the acoustic radiation efficiency also tends to move to the lower frequency,at the same time,it is found that with the decrease of the thickness,the valley value of the radiated sound power of the annular plate tends to move up obviously,while when the elastic modulus and the thickness decrease obviously,the acoustic radiation efficiency of the annular plate at high frequency decreases significantly.The coupling dynamic model of rotating annular plate and multi frequency DVAs is established.The influence of mass ratio,frequency ratio,damping ratio,installation position,distribution strategy and other parameters on the noise suppression effect of the DVAs is studied.The influence of the parameters of DVAs obtained from the method of the two degree of freedom system and the determination method of introducing mode function is compared.It is found that increasing the mass ratio,installing the DVAs at the maximum modal displacement of the annular plate and setting the frequency ratio to 1 can improve the noise suppression effect of the DVAs.Besides,under the same distribution strategy the centralized and uniform distribution of the DVAs have the same noise suppression effect,the determination method with mode shapes is more effective than the classical method.Taking the train wheel as an example,the vibration and noise control experiment of multi frequency DVAs is carried out.First of all,through experiments and two degree of freedom model,it is proposed and proved that there is an optimal contact stiffness between wheel modes and exsiting ring damper,and with the increase of preload of the ring damper,the contact stiffness between wheel modes and ring damper will experience the process of "below — reach — exceed" the optimal value from low frequency to high frequency.The modal strain energy distribution of the wheel is calculated,and a new type of ring damper structure with the same characteristics of multi frequency DVAs is proposed.Based on the existing ring damper,a new type of ring damper structure with the same characteristics of multi frequency dynamic absorber is proposed.The modal,transfer function and radiated sound pressure of the wheel with the existing ring damper and the new ring damper are tested.It is found that the new ring damper has better vibration and noise suppression effect than the existing ring damper.In this paper,the influence of rotating speed,geometric parameters,material parameters and boundary conditions on the dynamic frequency,radiated sound power and sound radiation efficiency of the rotating annular plate is analyzed.The theoretical model of rotating annular plate with additional multi frequency DVAs is established and the parameters optimized are carried out,and the constrained layer damping ring structure with the characteristics of the multi frequency DVAs is proposed.The relevant research results provide theoretical support and engineering reference for the low noise structural design and vibration and noise control methods of rotating annular plate components.