Effect Of Damping Component Temperature Variation On Vehicle Interior Noise In High Speed Train

Today the comfort of the train is becoming more and more important,the noise evaluation has become an important index to measure the performance of the train.With the opening of high and cold environment areas and long span high-speed railway,it is necessary to study the internal noise of high speed trains under different ambient temperatures.The vehicle body vibration and sound insulation is the main control method of vehicle interior noise.The vibration reduction performance of the car body depends on the vibration reduction performance of each damper.The strength of the sound insulation energy of the car body is directly related to the damping value of the car body plate,and both of them have a great influence on the environmental temperatures.The damping layer is usually coated on the vehicle body plate to reduce the vibration.Firstly,the characteristics of the damping material affected by temperature are analyzed,and the temperature of the damping material at the room temperature and outside of the vehicle is calculated by using the heat conduction law.Using the natural environment to realize the change of the environmental temperature,the attenuation characteristics of the plate are tested by the free attenuation method of hammer hammering,and then the damping ratio is calculated to get the relationship between the damping ratio and the temperature.The loss factor of the plate shows a tendency to increase first and then decrease with the change of temperature.The loss factor is obviously smaller at low temperature and high temperature.The temperature will affect the viscosity of hydraulic oil to change the damping characteristics of the damper,and then directly affect the vibration of the vehicle body.The working principle of shock absorber is analyzed,and the thermodynamic model is established by combining the law of thermodynamics.The damping coefficient under low temperature,normal temperature and high temperature environment is simulated and used as the simulation parameters of vehicle dynamics model.The elastic model of wheel set,frame and car body is established,and then the dynamic model is introduced.The force excitation of car body under typical temperature is obtained by simulation.Through simulation,the force excitation of vehicle body at different temperatures is compared.It is concluded that low temperature environment will increase the force excited by the car body and have adverse effects on the train operation,and a certain degree of high temperature environment will reduce the force excitation of the car body.The sound and vibration test of the real car is carried out to understand the noise inside and outside the high-speed train,and the noise excitation of the vehicle is obtained,which provides the basis for the next step noise simulation.VA one is used to simulate 'and predict the vehicle interior noise,the NVH model of the head car is established,and the simulation parameters such as plate damping and car body excitation under different environmental temperature are input.It is concluded that the low temperature operating environment increases the noise in the vehicle,and the noise in the vehicle is reduced by a certain degree of high temperature operating environment.