Research On Characteristics Of Noise In Subway Cars

With the continuous development of urban economy,traffic congestion has become increasingly serious.and subway vehicles rapid development because of large capacity,fast speed,saving the City Road area and other advantages.Subway lines in first-tier cities in China have relatively complete.at present the second line,third line cities are preparing the subway.As the city’s main traffic tools,the noise of the car is becoming more and more attention.The interior noise not only affects the comfort of passengers but also affect the fatigue life of subway vehicle parts,so the research of subway interior noise has high application value.This paper mainly study the interior noise and the vibration of cab seat in metro vehicle.Noise and vibration of metro vehicle are tested by HEAD acoustics noise and vibration test analysis system.In this paper,the noise distribution of different locations in the same speed is analyzed,the sound pressure level of each measuring point at different speed is compared,the influence of different operation lines and different curve radius on the internal noise of the vehicle are studied.The analysis shows that,the main noise sources of the vehicle are wheel rail noise and the noise of vehicle accessories,the noise sound pressure level of the near floor,the cross channel and the door is 2～3dB(A)higher than other measurement points,the noise near the roof mainly comes from the mechanical vibration of the air conditioning unit and the aerodynamic force of air outlet,when the frequency is above 500Hz,the sound pressure level increases with the increase of speed,when the vehicle passes through the switch,the noise value is 11.6dB(A)higher than that through the straight line,2.1dB(A)higher than that through the curve,when the curve radius is less than 1000m,the smaller the radius of the curve,the greater the contribution of the noise in the car,the noise sound pressure level in the passenger compartment is 2～3dB(A)higher than that in the drivers’ room,the running speed of the car has a great influence on the vibration acceleration of the cab seat,when the running line is a turnout,the longitudinal acceleration is larger.As a result of the sound insulation performance of metro vehicle floor has a direct impact on the noise of metro vehicles,this paper carries on the experiment of sound insulation of metro vehicles in the sound insulation room,sound insulation quantity of different floor structure of metro vehicle is measured and analyzed.Experimental result shows that,floor structure without installing sound insulation material that the frequency range is in 200～1000Hz,the sound insulation quantity of the floor is not more than 25dB(A),the sound insulation quantity is small,mid and high frequency sound insulation effect is good.In order to improve the ride comfort,install sound insulation material on the original floor.The sound insulation performance of the floor structure of the installation of the sound insulation material is obvious.Improving the sound insulation of the subway floor can effectively reduce the noise of the metro vehicle,and improve the comfort of the ride.The results of this study have a certain reference value for the design of metro vehicle vibration and noise reduction.