扣件刚度与阻尼对铁路箱梁车致振动噪声的影响研究

Effects of fastener stiffness and damping on structure-borne noise of railway box-girders

为了探明扣件刚度和阻尼对箱梁结构噪声的影响,基于车-线-桥耦合振动理论和声学边界元理论,建立了箱梁结构噪声预测的混合有限元-边界元法,并进行现场试验验证。在此基础上,分析了扣件刚度与阻尼对32 m简支箱梁结构噪声的声场分布规律与频谱特性、轮轨相互作用力的影响规律。结果表明：混合有限元-边界元法能较好地预测箱梁结构噪声,结构噪声的峰值频段为40~80 Hz,噪声峰值频率主要受扣件刚度的影响;距地面1.2 m高,近轨侧10~40 m和40~100 m范围内的声压级衰减率为0.29 d B（Lin）/m和0.067 d B（Lin）/m;扣件刚度增加将显著降低梁侧声场的指向角,扣件刚度自10 MN/m增加到100 MN/m时,近轨侧30 m纵断面的声压级平均增加12.5 d B（Lin）,结构噪声和轮轨力的峰值频率均从30 Hz同步增大到67 Hz;扣件阻尼比对梁侧声场的指向性影响较小,扣件阻尼比从0.062 5增加到0.5时,近轨侧30 m纵断面的声压级平均降低5.0 d B（Lin）,结构噪声和轮轨力的峰值频率均保持不变。

In order to analyze effects of fastener stiffness and damping on noise of railway box-girders,a mixed FEM-BEM noise prediction model based on the train-track-bridge coupled vibration theory and the acoustical BEM theory was built and validated with field tests. A 32 m simply-supported box-girder was taken as a study object,the effects of fastener stiffness and damping on distribution laws of noise field,characteristics of noise spectra and wheel / rail interaction force were investigated. Results showed that the mixed FEM-BEM model is a good predictor,the dominant frequency range of structure-borne noise is 40 ~ 80 Hz mainly depending on fastener stiffness; the sound pressure levels（ SPLs） of field points with a height of 1. 2 m from the ground have an attenuation rate of 0. 29 d B（ Lin） / m within a distance of 10 ~40m from the nearest track central-line and 0. 067 d B（ Lin） / m within a distance of 40 ~100 m from the nearest track central-line,respectively; the direction angle of structure-borne noise decreases with increase in fastener stiffness; when fastener stiffness grows from 10 MN / m to 100 MN / m,the average SPLs increase 12. 5 d B（ Lin） for field points in the longitudinal section within a distance of 30 m from the nearest track centerline; the peak frequencies of structure-borne noise and wheel / rail interaction force grow from 30 Hz to 67 Hz simultaneously; fastener damping has little effect on the directivity of the noise field; when the fastener damping ratio grows from 0. 0625 to 0. 5,the average SPLs decrease 5. 0d B（ Lin） for field points in the longitudinal section within a distance of 30 m from the nearest track centerline,and the peak frequencies of structure-borne noise and wheel / rail interaction force remain unchanged.