Indendification of Noise and Vibration Source Using Acoustic Double Holography Method

在噪声控制和降噪技术中，特别是在交通运输和车辆工程领域，目前已经提出了几种声噪声源识别技术。其中，基于声波反向传播的声全息技术在噪声源识别中获得了较高的分辨率和精度。例如，为此提出了近场声全息（NAH）方法，利用探测源^<(1)>的近场倏逝波分量。然而，这种方法对倏逝波的检测需要近场设置测量装置，而且测量数据的分析仪器也比较复杂。本文提出的声双全息（ADH）方法是一种进一步发展和简化的方法，可以实现比传统的声全息（AH）方法更高的识别噪声源平面的分辨率。ADH法基本利用双测量平面，不需要近场测量装置，不需要像NAH法那样进行复杂的分析。本方法可用于各种运输系统的噪声识别，包括在运行条件下的发动机噪声检测，而无需对测量装置进行特殊的测试处理。通过这些工作，得到以下结论。(1)声光双全息（ADH）方法在噪声源识别方面比传统的声光双全息（AH）方法具有更高的分辨率。(2)与常规方法一样，可以在单位波长较远的区域内实现ADH测量，并且可以确定测量时间。(3)在ADH方法中可以给出ADH测量系统的简单仪器。

Several kinds of the sound noise source identification techniques have been so far proposed in the noise control and noise reduction technologies, in particular, in the field of transport and vehicle engineering. Among those, acoustic holography methods based on the backward propagation of sound have been investigated for getting high ad accurate resolutionability in the noise source identification. For example, the nearfield acoustic holography (NAH) method was proposed for this purpose utilizing the detection of evanescent wave components in nearfield of the source^<(1)>. However, the detection of the evanescent wave in this method requires nearfield setting of the measuring devices and also somehow complicated analytical instruments for measured data.The acoustic double holography (ADH) method proposed in this paper is a further developed and simplified approach which could vealize higher resolution of the identified noise source plane over conventional acoustic holography (AH) methods. The ADH method basically makes use of dual measuring planes and dose not require nearfield measuring devices and complex analysis such as NAH methods. This Method can be applied to the sound noise identification of various types of transport systems including engine noise detection under operating condition without specific test-treatment for the measuring devices.Thorough these works, following conclusions are obtained.(1) The acoustic double holography (ADH) method can provide higher resolutionability in the noise source identification compared with the conventional AH method.(2) The ADH measurement can be realized in far distant area from unit wave length and measuring time can be determined as same as that in the conventional method.(3) Simple instrumentation of the ADH measuring system can be given in the ADH approach.