水下离散式消声器阵列机理研究

发布时间：2018-05-14 21:39

本文选题：潜艇 + 隐身技术　；参考：《哈尔滨工程大学》2014年硕士论文

【摘要】：本文根据连续式消声覆盖层已难以实现低频消声的问题,提出了离散式阵列消声结构,即是在耐压金属空腔结构表面敷设粘弹性材料构成一个声学单元,再将系列声学单元排列形成离散式消声器阵列。本文首先采用有限元方法对水下离散式消声器阵列机理进行了理论研究。为了便于机理研究,将声学单元周期排列,放入无限大水介质中,取水介质、结构和边界面组成的一个周期单元,用ANSYS软件进行有限单元网格划分。周期单元为一个六面体,包括入射波端面、透射波端面以及由于结构周期性产生的四个面,在这四个面上,依据Bloch理论,节点声压和位移存在周期关系。由于现有的有限元软件不能处理这种周期边界条件,所以本文采用自编有限元程序对水下离散式消声器阵列的声学性能进行仿真分析。采用解析方法对水下弹性体(球、球壳)的散射声场进行了仿真分析,推导了敷设粘弹性材料球壳的散射声场的解析解,了解了一个声学单元的散射特性,为水下离散式消声器阵列声学单元的选取提供了依据。数值分析了水下离散式消声器阵列的隔声性能,对比分析了不同类型的声学单元对隔声效果的影响。针对同一种声学单元,探讨了声学单元大小、粘弹性层材料参数(密度、杨氏模量、损耗因子、厚度、泊松比)的变化对消声器阵列隔声性能的影响。最后依照仿真中的消声器阵列结构模型,加工了五种声学单元,分别布放在压力罐的隔板上,在不同压力条件下,通过测量有无声学单元安装时远场的辐射声功率,试验研究水下离散式消声器阵列的隔声性能。试验数据分析结果表明:有限元方法对于研究水下离散式消声器阵列的隔声性能是适用的;水下离散式消声器阵列对低频段隔声是有效的。
[Abstract]:In this paper, according to the problem that it is difficult to realize low frequency noise suppression in continuous anechoic coating, a discrete array structure is proposed, that is, a viscoelastic material is laid on the surface of a pressure resistant metal cavity structure to form an acoustic unit. Then a series of acoustic units are arranged to form a discrete muffler array. In this paper, the mechanism of underwater discrete muffler array is studied by finite element method. In order to study the mechanism, the acoustic elements are arranged periodically and put into infinite water medium, a periodic unit composed of water collecting medium, structure and boundary surface. The finite element mesh is divided by ANSYS software. The periodic element is a hexahedron, which consists of the end plane of the incident wave, the end plane of the transmission wave and the four surfaces produced by the periodicity of the structure. According to the Bloch theory, there exists a periodic relationship between the nodal sound pressure and the displacement. Because the existing finite element software can not deal with this periodic boundary condition, the acoustic performance of the underwater discrete muffler array is simulated and analyzed by using the self-compiled finite element program. The scattering sound field of an underwater elastic body (sphere, shell) is simulated by analytical method. The analytical solution of the scattering sound field of a spherical shell with viscoelastic material is derived, and the scattering characteristics of an acoustic unit are understood. It provides a basis for the selection of acoustic elements of underwater discrete muffler array. The sound insulation performance of underwater discrete muffler array is numerically analyzed, and the effects of different acoustic elements on the sound insulation effect are compared and analyzed. The effects of the size of acoustic units and the material parameters of viscoelastic layer (density, Young's modulus, loss factor, thickness, Poisson's ratio) on the sound insulation of the muffler array are discussed. Finally, according to the silencer array structure model in the simulation, five acoustic units are machined and placed on the diaphragm of the pressure tank respectively. Under different pressure conditions, the radiated sound power in the far field is measured by measuring whether there are acoustic units installed in the far field. The sound insulation performance of underwater discrete muffler array is studied experimentally. The experimental results show that the finite element method is suitable for studying the sound insulation performance of underwater discrete muffler array, and the underwater discrete muffler array is effective for low frequency band sound insulation.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB565

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