水下多层复合结构低频吸声特性研究
文献类型：学位论文
| 作者 | 孙汉民 |
| 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 | 水声材料 低频 多层复合结构 多孔介质 传递矩阵 等效参数 |
| 中文摘要 | 传统的吸声层由于低频的限制已不能应对水下低频吸声的要求，本文针对水声材料低频吸声问题，采用建立理论模型和数值计算等方法，进行了初步探讨，提出了改善水下低频吸声的措施。根据多层介质声传播理论，采用传递矩阵方法，研究了均匀材料的吸声特性，分析了影响其吸声性能的因素，主要包括模量，损耗因子，厚度，背衬等。仅仅依靠材料本身很难达到高的低频吸声效果，通过优化分析表明，采用合理的多层结构可以大大提高低频吸声J性能。采用等效参数等方法，分析了带有空腔类结构的吸声材料的性能。阻抗过渡形式刘吸声性能有明显影响，指数过渡优于线性和二次函数形式的过渡。空腔浓度对结构吸声影响显著。谐振腔结构可以改善低频吸声性能。对多孔介质层，分别采用Attenborough刚性模型和Biot弹性模型研究了其吸声性质，分析了骨架参数和多孔介质中的粘性流体对其吸声性能的影响。采用传递矩阵法，对带有多孔介质层的复合多层结构进行了研究。结果表明，这一结构大大提高了低频的吸声效果。本文的特点，对材料的低频吸声性能进行了系统地研究，对影响其吸声系数的因素进行了比较全面的分析，提出了带有充满高粘滞流体多孔介质的多层复合结构，这一结构大大提高了低频吸声效果。本文得出的结论，对研制低频吸声结构有一定的借鉴作用。 |
| 英文摘要 | As the frequency of underwater source is becoming lower, traditional anechoic coatings could not work well in low frequency range. In this paper, how to improve the sound absorption coefficient of anechoic coatings in low frequency range is studied, and present the absorbent model and numerical prediction. The transfer matrix is used to study the layered structure. To homogeneous, the effect to sound absorption is analyzed, including complex module, thickness and backed factor. We could not get the desired sound absorption coefficient by the one-layer structure. According to optimization, sound absorption coefficient can be improved great by using sound multi-layer structure. To the structure including cavities, equivalent parameter is used. To impedance transition structure, exponential transition is prior to linear transition and quadratic transition. The inner structure such as cavities can scatter sound energy, produce resonance and convert longitudinal wave to transverse wave, and then enhance the sound absorption coefficient. To porous materials, Attenborough model and Biot model is used respectively, the effect of the parameters of the bone and fluid is analyzed. To composite multi-layered structure, the transfer matrix is also used, and sound absorption coefficient in low frequency range is enhanced. The highlight in the thesis is that sound absorption in low frequency range of anechoic coatings is studied in the round, and the composite multi-layer structure is present, and the absorption coefficient in low frequency is improved. Some significant results are obtained, and it is for reference to design new absorbent structure. |
| 语种 | 中文 |
| 公开日期 | 2011-05-07 |
| 页码 | 52 |
| 源URL | [http://159.226.59.140/handle/311008/992]  |
| 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 | 孙汉民. 水下多层复合结构低频吸声特性研究[D]. 中国科学院声学研究所. 中国科学院声学研究所. 2005. |
入库方式： OAI收割
来源：声学研究所
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