Noise is one of the key issues in the operation of high-speed railways, with sound source localisation and its transfer path as the two major aspects. This study investigates both the exterior and interior sound sourc...Noise is one of the key issues in the operation of high-speed railways, with sound source localisation and its transfer path as the two major aspects. This study investigates both the exterior and interior sound source distribution of a high-speed train and presents a method for performing the contribution analysis of airborne sound with regard to the interior noise. First, both exterior and interior sound source locations of the high-speed train are identified through in-situ measurements. Second, the sound source contribution for di erent regions of the train and the relationships between the exterior and interior noises are analysed. Third, a method for conducting the contribution analysis of airborne sound with regard to the interior noise of the high-speed train is described. Lastly, a case study on the sidewall area is carried out, and the contribution of airborne sound to the interior noise of this area is obtained. The results show that, when the high-speed train runs at 310 km/h, dominant exterior sound sources are located in the bogie and pantograph regions, while main interior sound sources are located at the sidewall and roof. The interior noise, the bogie area noise and the sound source at the middle of the coach exhibit very similar rates of increase with increasing train speed. For the selected sidewall area, structure-borne sound dominates in most of the 1/3 octave bands.展开更多
Acoustic signals from diesel engines contain useful information but also include considerable noise components To extract information for condition monitoring purposes, continuous wavelet transform (CWT) is used for t...Acoustic signals from diesel engines contain useful information but also include considerable noise components To extract information for condition monitoring purposes, continuous wavelet transform (CWT) is used for the characterization of engine acoustics. This paper first reviews CWT characteristics represented by short duration transient signals. Wavelet selection and CWT are then implemented and wavelet transform is used to analyze the major sources of the engine front's exterior radiation sound. The research provides a reliable basis for engineering practice to reduce vehicle sound level. Comparison of the identification results of the measured acoustic signals with the identification results of the measured surface vibration showed good agreement.展开更多
球阵列波束形成是一种有效的三维空间声源识别技术,已有的球谐函数波束形成方法虽然能够准确定位声源,但无法定量声源的声学贡献,且声源识别结果受聚焦距离影响显著。通常,各声源对阵列中心处的声压贡献是声源排序评价的有效依据,为准...球阵列波束形成是一种有效的三维空间声源识别技术,已有的球谐函数波束形成方法虽然能够准确定位声源,但无法定量声源的声学贡献,且声源识别结果受聚焦距离影响显著。通常,各声源对阵列中心处的声压贡献是声源排序评价的有效依据,为准确计算该声压贡献,提出球谐函数波束形成扩展方法,探究聚焦距离对计算准确性的影响规律。针对已知声源的模拟仿真结果表明,该方法不仅能够准确定位声源,而且能够准确计算声源声压贡献,3 000 Hz以下频段的最大误差不超过0.5 d B,3 000~6 000 Hz频段的最大误差不超过1.5 d B,且准确性几乎不受聚焦距离的影响。扬声器声源试验证明了模拟计算的正确性及该方法在实际应用中的有效性。展开更多
A schematic to make the spectra of the exterior noise of high speed railway was put forward. The exterior noise spectrum was defined based on the characteristics of the high-speed train exterior noise. Its characteris...A schematic to make the spectra of the exterior noise of high speed railway was put forward. The exterior noise spectrum was defined based on the characteristics of the high-speed train exterior noise. Its characteristics considered here include identifying the exterior main sources and their locations, their frequency components including the Doppler effect due to the noise sources moving at high speed, the sound field intensity around the train in high-speed operation, the sound radiation path out of the train, and the pressure level and frequency components of the noise at the measuring points specified by the International Organization for Standardization(ISO). The characteristics of the high-speed train exterior noise of the high speed railways in operation were introduced. The advanced measuring systems and their principles for clearly indentifying the exterior noise sources were discussed in detail. Based on the concerned noise results measured at sites, a prediction model was developed to calculate the sound level and the characteristics of the exterior noise at any point where it is difficult to measure and to help to make the exterior noise spectrums. This model was also verified with the test results. The verification shows that there is a good agreement between the theoretical and experimental results.展开更多
基金Supported by National Key R&D Program of China(Grant No.2016YFE0205200)National Natural Science Foundation of China(Grant No.U1834201)
文摘Noise is one of the key issues in the operation of high-speed railways, with sound source localisation and its transfer path as the two major aspects. This study investigates both the exterior and interior sound source distribution of a high-speed train and presents a method for performing the contribution analysis of airborne sound with regard to the interior noise. First, both exterior and interior sound source locations of the high-speed train are identified through in-situ measurements. Second, the sound source contribution for di erent regions of the train and the relationships between the exterior and interior noises are analysed. Third, a method for conducting the contribution analysis of airborne sound with regard to the interior noise of the high-speed train is described. Lastly, a case study on the sidewall area is carried out, and the contribution of airborne sound to the interior noise of this area is obtained. The results show that, when the high-speed train runs at 310 km/h, dominant exterior sound sources are located in the bogie and pantograph regions, while main interior sound sources are located at the sidewall and roof. The interior noise, the bogie area noise and the sound source at the middle of the coach exhibit very similar rates of increase with increasing train speed. For the selected sidewall area, structure-borne sound dominates in most of the 1/3 octave bands.
基金Project (No. 50175078) supported by the National Natural Science Foundation of China
文摘Acoustic signals from diesel engines contain useful information but also include considerable noise components To extract information for condition monitoring purposes, continuous wavelet transform (CWT) is used for the characterization of engine acoustics. This paper first reviews CWT characteristics represented by short duration transient signals. Wavelet selection and CWT are then implemented and wavelet transform is used to analyze the major sources of the engine front's exterior radiation sound. The research provides a reliable basis for engineering practice to reduce vehicle sound level. Comparison of the identification results of the measured acoustic signals with the identification results of the measured surface vibration showed good agreement.
文摘球阵列波束形成是一种有效的三维空间声源识别技术,已有的球谐函数波束形成方法虽然能够准确定位声源,但无法定量声源的声学贡献,且声源识别结果受聚焦距离影响显著。通常,各声源对阵列中心处的声压贡献是声源排序评价的有效依据,为准确计算该声压贡献,提出球谐函数波束形成扩展方法,探究聚焦距离对计算准确性的影响规律。针对已知声源的模拟仿真结果表明,该方法不仅能够准确定位声源,而且能够准确计算声源声压贡献,3 000 Hz以下频段的最大误差不超过0.5 d B,3 000~6 000 Hz频段的最大误差不超过1.5 d B,且准确性几乎不受聚焦距离的影响。扬声器声源试验证明了模拟计算的正确性及该方法在实际应用中的有效性。
基金Project(2682013BR009)supported by the Fundamental Research Funds of the Central Universities,ChinaProject(2011AA11A103-2-2)the National High-Technology Research and Development Program of China
文摘A schematic to make the spectra of the exterior noise of high speed railway was put forward. The exterior noise spectrum was defined based on the characteristics of the high-speed train exterior noise. Its characteristics considered here include identifying the exterior main sources and their locations, their frequency components including the Doppler effect due to the noise sources moving at high speed, the sound field intensity around the train in high-speed operation, the sound radiation path out of the train, and the pressure level and frequency components of the noise at the measuring points specified by the International Organization for Standardization(ISO). The characteristics of the high-speed train exterior noise of the high speed railways in operation were introduced. The advanced measuring systems and their principles for clearly indentifying the exterior noise sources were discussed in detail. Based on the concerned noise results measured at sites, a prediction model was developed to calculate the sound level and the characteristics of the exterior noise at any point where it is difficult to measure and to help to make the exterior noise spectrums. This model was also verified with the test results. The verification shows that there is a good agreement between the theoretical and experimental results.
