水下消声层的声特性研究
文献类型：学位论文
| 作者 | 安俊英 |
| 学位类别 | 博士 |
| 答辩日期 | 2004 |
| 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 | 消声层 多层 参数匹配 有限元 结构 |
| 其他题名 | Study of the sound characteristics of underwater anechoic coating |
| 中文摘要 | 消声层在水下工程中应用极其广泛，不仅能减小目标强度，而且还能降低辐射噪声，因此研究其声特性具有重要意义。本文根据分层介质中的波动理论，采用传递矩阵方法研究均匀单层、多层消声层的声特性，分析材料参数对声特性的影响；运用参数匹配方法对均匀消声层的声特性进行控制；采用有限元方法研究含结构消声层的声特性，计算了空气腔、余属球及硬壳结构的反射特性、位移谐振模态，分析了结构及背衬的影响。研究表明：1．提高消声层的消声性能，要求材料的阻抗与水匹配，减小高频反射；慢声速，降低谐振频率；高阻尼，减小反射系数及其随频率的起伏。多消声层的性能优于单层，多层结构可实现阻抗匹配、降低谐振频率及去稠减振等多功能。参数匹配技术可以控制消声层的声特性，对消声瓦的设计有重要作用。2．有限元方法是求解微分方程边值问题的有效数值技术，能得到消声层的声传播特性和振动模态，为开发消声瓦提供理论依据。消声层内的空气腔等结构能极大的改变消声层的声特性，内部结构的作用是散射声能、产生谐振和波型转换。谐振产生强吸收作用，而波型转换主要是纵波转换为具有高衰减的横波，增加声能量耗损。因此，可以通过改变空腔的形状、大小、位置及间距，对声特性进行控制；对含金属球、硬壳结构消声层的研究表明，余属球、硬壳在部分频段上能改善消声层的声特性；另外，背衬对声特性也有很大影响。论文的特色是用数值技术研究水下消声层的声特性，重点研究消声层内的声传播和消声机理，所得结果为消声瓦开发提供理论依据，其参数选择、结构设计，对I程应用具参考价值。 |
| 英文摘要 | Anechoic coating is widely used in underwater engineering. It plays a key role in reducing the target strength and radiated noise. So the study of it is significant. Based on the waves theory in layered medium, the transfer matrix method is used to study the characteristics of single and multiple homogeneous layers and analyze the effect of the parameters of material. With application of the parameter-match method, the performance of multiple layers is controlled. The FEM (Finite Element Method) is used to study the reflection characteristics and resonance modes of coatings involving air-filled cavities, metal spheres and hard shells. Also the effect of structure and backing are analyzed. The result shows: 1. To improve the anechoic performance of coating, material should comply with three requirements. Impedance matches with water to reduce the reflection of high frequencies. Slow down the sound velocity to decrease the resonance frequencies. Highly damped to reduce the reflection coefficient and the fluctuation with frequency. The performance of multi-layer is superior to single layer. Multi-layer can attain multifunction such as impedance match, decreasing resonance frequency and decoupling. The performance of coating can be controlled by the parameter-match method, which is important for the design of anechoic tile. 2. The FEM is an efficient numerical method used to solve the boundary' problem of differential equation. It can calculate the propagation characteristics and resonance modes and provide theoretical basis for developing anechoic tile. Structure in coating such as air cavities can change the reflection characteristics greatly. The functions of inner structure are to scatter sound energy, create resonance and convert wave mode. Resonance causes strong absorption, while wave mode conversion can increase energy loss by converting longitudinal wave to transverse wave damped highly. Therefore the performance of coating can be controlled by changing the shape, size, location and interval of the cavities. Result shows that metal spheres and hard shells in the coating will improve the anechoic performance at some frequency bands. Moreover, backing also affects the performance of the coating significantly. The feature of this paper is the study of the sound characteristics of underwater anechoic coating by numerical technology. Study focuses on the sound propagation and anechoic mechanism. The result provides theoretical basis for the development of new tile, the parameter selection and structure design have great value for reference in engineering application. |
| 语种 | 中文 |
| 公开日期 | 2011-05-07 |
| 页码 | 45 |
| 源URL | [http://159.226.59.140/handle/311008/872]  |
| 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 | 安俊英. 水下消声层的声特性研究[D]. 中国科学院声学研究所. 中国科学院声学研究所. 2004. |
入库方式： OAI收割
来源：声学研究所
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