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题名	声子晶体声学性能表征参数测试方法研究
作者	周启君
学位类别	博士
答辩日期	2005
授予单位	中国科学院声学研究所
授予地点	中国科学院声学研究所
关键词	声子晶体 双传声器 四传声器 传递损失
其他题名	Research on theMeasunementMethod of the Acoustical Parameters of Phononic Crystal
中文摘要	本文研究的是声子晶体声学表征参数测试理论。声子晶体是由两种或两种以上不同材料构成的结构性功能材料，具有声波禁带特性。声子晶体作为声学材料具有普通声学材料的共性，有反射系数、吸声系数、法向声阻抗率等声学表征参数；作为特定种类的声学材料，声波禁带是声子晶体区别于其它声学材料的最主要声学特征，其实质就是频率落在禁带范围内的声波不能传播。声波透过材料?继续传播的性质用具体的声学参数表示就是透射系数，或者用传声损失来表示。因此刘一声子晶体声波禁带的测量就是对传声损失的测量。声子晶体的另一个重要特征是负弹性模量，负弹性模量是以传统质量隔声定律来解释声子晶体传声损失时引入的新概念，是通过对传声损失的反演得到的，对负弹性模量的测量归结于对传声损失的测量。声波禁带与负弹性模量是同一物理事实不同角度的物理描述，依据的本质都是弹性波在材料中不能传播。本文从声子晶体声学性能特别是传递损失白勺特征出发，在现有声学性能测量理论中选定了双传声器传递函数法作为声子晶体声学性能表征参数的测试方法。在理论分析及实验验证中发现，J．YCllullg提出的两对双传声器测量传递损失的理论存在物理定义上的不足，并在实验上给予了证明。论文从传递损失的定义出发，提出了互易材料（材料两面的反射系数与透射系数相同）与非互易材料（材料两面的反射系数与透射系数不同）传递损失的测量理论公式，对于非互易材料提出两种测量方法，即：交换入射面法与两次测量法，编写了相应的计算公式。对传递损失进行了误差分析，设计构造了两套实验装置，能满足频率范围为50Hz-2kHz的测量需要。为了验证传递损失测量理论，设计了单腔消声器、变截而消声器作为验证载体，实验结果与理论符合，从而验证了传递损失测量理论。从实验中发现交换入射面法可以有效的消除测试系统固有误差，测试互易材料传递损失若也采用交换入射面法能有效降低测试误差。此外，提出了双声源测试系统，能避免交换入射面带来的工作量和额外操作误差。本文传声损失测量理论是由声子晶体测量需要引入，但并没有加之任何特殊的限定，因此可以应用于材料传声损失的测量中。目前还没有阻抗管中测量材料传声损失的方法与国际国内标准，因此根据传递损失测量理论及对声子晶体测试系统的研究起草了中华人民共和国国家标准《声学阻抗管中传声损失的测量一四传声器法》的讨论稿，已提交声学标准归口专业委员会批准。本文的理论研究工作丰富和发展了连续谱测量小尺寸样品传递损失的测量理论，将与隔声室测量材料的传声损失方法一起用于材料传声损失的测量。
英文摘要	The paper aims at investigating the measurement theory of acoustic parameters of phononic crystal. Phononic crystal is a kind of structure-based functional material with sound bandgap, which is made from two or more classes of different material. As common acoustical material, sonic crystal is of reflection coefficient, absorption coefficient and normal resistance; but as special acoustical material, it is characterized with bandgap. If the frequency of a sound wave falls in the bandgap, the sound wave can not propagate through the relevant phononic crystal, otherwise, can do. The measurement for this kind of capability of phononic ciystal can finally be owed to the one for sound transmission loss. The other important characteristic of sonic crystal is the negative elastic constant at certain frequency ranges, which is introduced in when trying to explain the bandgap with traditional mass density law for sound shielding. It can also be measured by measuring sound transmission loss. Based on the acoustical characteristics, especially on the transmission loss, of phononic crystal, transfer function method with two microphones is chosen from existing acoustical measuring methods as the measurement method of the special acoustical parameters of phononic crystal. After theoretically analysis and experimentally check, we found there is a mistake in the measurement theory for transmission loss with two couples of microphones offered by J. Y. Chung, Originated from the definition of the material transmission loss, two measurment formulae for transmission loss have been deduced in detail for exchangeable material the reflection coefficients and perspective coefficients of the two surfaces of which are equal respectively, and for unexchangeable material ones of which are completely different from, respectively. For unexchangeable material, two measurement methods have been acquired, which are exchanging-incident-face method and two-time measurement method. Accordingly, the calculating programs were written. The error analysis method of the transfer function developed by F. Seybert has been applied to the one of the transmission loss. In the light of the conclusion of the error influence analysis, two experimental systems has been devised and made at the aim of satisfying the measuring need ranging from 50 to 2000Hz. In order to testify the measuring theory of transmission loss, some experimental devices, such as single-chamber silencer, cross-changing silencer and anechoic termination, have been devised and used, and it has been showed that the testing results agree with the ones calculated from the theory. Thus, the theory has been testified right. Based on the measuring theory of transmission loss developed by us, the national standard of the People's Republic of China "Acoustics—Determination of sound transmission loss—four microphone method" has already been written, and submitted to the special committee responsible for acoustical measurement for approval.The work lichens and develops the theory on measuring transmission loss in continual spectrum of small size sample, and together with insulating room method, will compose of more complete measuring theoretical system of transmission loss of material.
语种	中文
公开日期	2011-05-07
页码	111
内容类型	学位论文
源URL	[http://159.226.59.140/handle/311008/932]
专题	声学研究所_声学所博硕士学位论文_1981-2009博硕士学位论文
推荐引用方式 GB/T 7714	周启君. 声子晶体声学性能表征参数测试方法研究[D]. 中国科学院声学研究所. 中国科学院声学研究所. 2005.

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