偏相干分析在客车降噪中的应用
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摘要
车内低频噪声一直是汽车NVH研究关注的重点问题,常需要找到对噪声影响较大的振动结构进行改进,但是振动对场点的贡献并不能代表对整个声场噪声的贡献量。针对多峰值多场点的车内声场问题,引入"总相干系数"和"相干系数和"的概念对现有的偏相干分析方法进行改进。对某型客车的车内噪声进行小波包分解,得到车内声场的声学特性,确定研究的频率范围。通过对各板件振动与车内测点噪声信号进行偏相干分析,确定对车内声场影响较大的结构,并在实车上实施了改进措施。结果表明,车内噪声测点声压级降低0.5 d B~2 d B,为有效降低客车车内噪声提供了指导方向。
Interior low-frequency noise has been the focus of automotive NVH research. It is necessary to detect and improve the vibrating structures that have great impact on the interior noise. However, contribution of vibration to the noise of field points is unlikely to completely represent the contribution to the whole interior acoustic field. For the interior acoustic field with multiple frequency peaks and multiple field points, the"total coherence coefficient"and"coherence coefficient sum"are introduced as two new parameters to improve the existing partial coherence analysis method. Then, the interior noise of a passenger car is analyzed by wavelet packet decomposition. The acoustic characteristics of the interior acoustic field and the concerned frequency range are obtained. Through the partial coherence analysis of the vibration of panels and interior noise signals at the measurement points, the structures which have greater impact on the interior noise are identified. And the improvement measures are carried out for the car. The results of the test show that the sound pressure level of the interior noise of the field points is reduced by 0.5 d B-2 d B. This work provides the guidance for reducing the interior noise of passenger cars.
Interior low-frequency noise has been the focus of automotive NVH research. It is necessary to detect and improve the vibrating structures that have great impact on the interior noise. However, contribution of vibration to the noise of field points is unlikely to completely represent the contribution to the whole interior acoustic field. For the interior acoustic field with multiple frequency peaks and multiple field points, the"total coherence coefficient"and"coherence coefficient sum"are introduced as two new parameters to improve the existing partial coherence analysis method. Then, the interior noise of a passenger car is analyzed by wavelet packet decomposition. The acoustic characteristics of the interior acoustic field and the concerned frequency range are obtained. Through the partial coherence analysis of the vibration of panels and interior noise signals at the measurement points, the structures which have greater impact on the interior noise are identified. And the improvement measures are carried out for the car. The results of the test show that the sound pressure level of the interior noise of the field points is reduced by 0.5 d B-2 d B. This work provides the guidance for reducing the interior noise of passenger cars.
引文
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[8]FAN R,SU Z,MENG G,et al.Application of sound intensity and partial coherence to identify interior noise sources on the high speed train[J].Mechanical Systems&Signal Processing,2014,46(2):481-493.
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[10]王梦璇.基于小波包分解的舰船辐射噪声特征提取方法研究[J].电子设计工程,2014,22(4):81-83.
[11]杨正理.采用小波能量的光纤周界报警信号辨识[J].压电与声光,2014,36(6):883-887.
[2]惠巍,刘更,吴立言.车内噪声预测与面板声学贡献度分析[J].噪声与振动控制,2006,26(5):62-66.
[3]韩旭,余海东,郭永进,等.基于壁板声学贡献分析的轿车乘员室声场降噪研究[J].上海交通大学学报,2008,42(8):1254-1258.
[4]白松,徐新喜,刘孝辉,等.车辆壁板声学贡献分析与降噪试验研究[J].振动与冲击,2013,32(24):204-208.
[5]张一麟,廖毅,莫品西,等.基于车身模态和板块贡献分析的阻尼优化降噪方法研究[J].振动与冲击,2015,34(4):153-157.
[6]赵海澜,汪鸿振.偏相干分析识别噪声源的计算[J].噪声与振动控制,2005,25(5):31-33.
[7]吴旭东,左曙光,芦勇,等.偏相干分析在燃料电池轿车噪声源识别中的应用[J].噪声与振动控制,2008,28(3):81-84.
[8]FAN R,SU Z,MENG G,et al.Application of sound intensity and partial coherence to identify interior noise sources on the high speed train[J].Mechanical Systems&Signal Processing,2014,46(2):481-493.
[9]王建锋,张维峰,李平.基于偏相干分析的大型客车振动源识别试验研究[J].汽车技术,2014(2):36-39.
[10]王梦璇.基于小波包分解的舰船辐射噪声特征提取方法研究[J].电子设计工程,2014,22(4):81-83.
[11]杨正理.采用小波能量的光纤周界报警信号辨识[J].压电与声光,2014,36(6):883-887.