小半径曲线对地铁车辆客室噪声偏高的影响分析

Analysis of Excessive Noise in Passenger Rooms of Metro Vehicles in Small Radius Curves

针对地铁车辆在通过小半径曲线时出现的客室噪声偏高问题,利用Brüel&Kjar测试系统分析车辆空调系统、轨道状态与车辆振动等因素对客室噪声的影响。分析结果表明,车辆在通过小半径曲线时,客室地板振动加速度是平直道的4.7倍;随车辆运行速度的增加,空调系统对客室噪声的影响逐渐减小;客室内主要噪声源位于门页上方胶条及地板处,与显著波长为25~40 mm的钢轨波磨相关。客室噪声主要受两方面因素影响:一方面是由于轨道对噪声衰减率较低,振动激励输入经“轴箱—构架—车体”沿垂向和横向振动传递,进而激励客室内装等结构振动产生辐射噪声;另一方面,钢轨辐射噪声经隧道壁面反射加强后,通过车门及地板隔声薄弱环节透射到车内。从小半径曲线车辆限速、轨道周期性打磨等方面提出改进建议。

Aiming at the problem of excessive noise in passenger rooms of metro vehicles in small radius curves,the influence of vehicle air conditioning system,track status and vehicle vibration on noise in passenger rooms was analyzed based on Brüel & Kj?r test system.The analysis results showed that the vibration acceleration of the passenger rooms floor was 4.7 times higher than that of the straight road when the vehicle running line was small radius curve;with the increasing of the vehicle running speed,the influence of air conditioning system on the passenger rooms noise decreased gradually;and the sound source was mainly located in the middle of the door page and the floor,which was related to the rail corrugation with the significant wavelength of 25~40 mm.Passenger rooms noise was mainly affected by two factors:on the one hand,due to the low track attenuation rate,the vibration excitation input was transmitted vertically and horizontally through axle box-frame-car body,thus stimulating the structural vibration of passenger rooms to produce radiated noise;on the other hand,the rail radiated noise was transmitted to the car through the weak links of door and floor insulation after the reflection of tunnel wall was strengthened.Suggestions for operation improvement were put forward in terms of speed limit of small radius curve vehicles and periodic rail grinding.