高速列车车内客室端部噪声分布特性与声学模态分析

Characteristics of Noise Distribution at the Ends of the Coach and Acoustic Modal Analysis of High-speed Train

基于现场测试,对高速列车车内客室端部噪声分布特性进行分析研究.结合车内、车下振动分析和车内空腔声学模态计算,明确车内客室端部噪声分布的形成机理,在此基础上提出高速列车车内客室端部噪声问题的改善建议.研究结果表明,高速列车车内客室端部靠窗位置和过道位置的横向距离为1.2～1.7m,但靠窗位置的噪声却比过道位置大8dB（A）左右.车内的噪声和车内、车下的振动加速度在111Hz附近均存在显著的峰值,这个频率正是列车在250km/h运行速度下的过枕跨参数激振频率.车内空腔声学模态在111Hz附近基本上表现为横向两侧大、中间小的状态.车体系统的结构振动和车内声学空腔存在相互耦合的关系,最终导致车内客室端部出现这种特殊的噪声分布.相关研究结果可为研究消除或降低高速列车车内异常噪声的措施提供参考.

The characteristics of noise distribution at the ends of the high-speed coach are studied by the means of field measurements.The interior and exterior vibration analysis and the interior cavity acoustic modal simulation are conducted to examine the characteristics of the noise distribution and figure out its mechanism.Counter measures against this kind of interior noise are proposed at the end.The measurements show that the sound pressure level at the seat by the windows is 8dB（A） higher than that by the aisle,although the horizontal distance between the two seats is only 1.2-1.7m.The interior noise,the interior and exterior vibration accelerations all have a peak frequency at 111Hz.This vibration frequency matches the passing frequency of sleeper span at the operation speed of 250km/h.And the acoustic modal analysis show that sound pressures are almost high on the sides and low in the middle at the cross section at 111Hz.It is found that the interaction between the structural vibrations of the car body and the interior cavity sound pressure is the reason for this special noise distribution at the ends of the coach.This work provides a theoretical basis for counter measures against the interior noise problems in high-speed trains.