水下吸声复合材料结构优化设计

发布时间：2018-05-03 16:04

本文选题：多孔材料 + 夹芯复合材料　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：随着当今舰船领域的快速发展,水下吸声复合材料的应用越来越重要。舰船的声隐身技术对其生存能力具有重要作用,如果采用吸声复合材料作为舰船的设计材料,可以有效提高其航行安全。多功能复合材料具有可设计性强的特点,开发和研制水下吸声复合材料对于舰船领域的应用有着广阔的前景。因此,对水下吸声复合材料的研究具有重要意义。本文的主要目的就是研究水下吸声复合材料在低频率下的吸声特性,用有限元计算方法,实现对材料的优化设计,提高其吸声性能。本文基于计算声学方法,对几种典型材料结构的低频吸声性能进行了模拟计算分析。材料结构主要包括:多孔复合材料、三明治夹芯复合材料结构。通过对水声材料的驻波管吸声性能试验进行数值模拟,计算了不同材料在驻波管内环境为水介质时的吸声系数,显示了不同频率下材料的吸声系数-频率曲线及驻波管内的声压云图分布情况,分析了不同复合材料在各频率下的水下吸声特性,实现了水下复合材料及结构的声学优化设计,具体研究内容如下:基于Allard—Johnson模型构建了多孔材料的声学计算模型,通过模拟驻波管吸声性能试验,研究了两种典型多孔吸声材料Si C及聚氨酯的吸声特性,并与相关文献进行了对比验证分析;以此为基础进一步计算了厚度为100mm的聚氨酯水下吸声特性,研究了孔隙率、流阻率、迂曲度等参数对材料吸声性能的影响,分析了不同频率下多孔材料的管内声压云图分布情况,揭示了多孔材料水下低频(0-1700Hz)吸声系数的变化规律及影响因素。根据上述理论及计算方法,本文构建了由多孔材料及纤维增强复合材料组成的夹芯结构声学计算模型,研究了三种不同表层夹芯结构的水下声学特性,分析了夹芯结构水下吸声性能的影响因素。最后,通过调整夹芯结构的复合材料参数,模拟计算了不同夹芯结构在垂直入射声波下的吸声系数。研究了表层材料、吸声芯材及夹芯结构形式对吸声特性的影响,给出了提高夹芯复合材料结构吸声系数的参数优化方案。
[Abstract]:With the rapid development of ship field, the application of underwater acoustic composite is becoming more and more important. The acoustic stealth technology plays an important role in the survival of ships. If the sound absorbing composite material is used as the design material of ships, the navigation safety can be improved effectively. Multifunctional composites have the characteristics of strong designability, and the development and development of underwater sound absorbing composites have a broad prospect in the field of ship applications. Therefore, the study of underwater sound absorption composites is of great significance. The main purpose of this paper is to study the sound absorption characteristics of underwater sound absorption composites at low frequencies. The optimum design of the materials is realized by using finite element method to improve their sound absorption performance. Based on the computational acoustics method, the low frequency sound absorption properties of several typical materials are simulated and analyzed. The material structure mainly includes: porous composite material, sandwich sandwich sandwich composite material structure. In this paper, the sound absorption coefficient of different materials in water medium in standing wave tube is calculated by numerical simulation of the sound absorption performance of standing wave tube. The sound absorption coefficient-frequency curves of materials and the distribution of sound pressure clouds in standing wave tubes are shown at different frequencies. The underwater sound absorption characteristics of different composite materials are analyzed, and the acoustic optimization design of underwater composite materials and structures is realized. The main contents are as follows: based on the Allard-Johnson model, the acoustic calculation model of porous materials is constructed. The sound absorption characteristics of two typical porous materials, sic and polyurethane, are studied by simulating the sound absorption performance of standing wave tube. The underwater sound absorption characteristics of polyurethane with thickness of 100mm are further calculated, and the effects of porosity, flow resistance and tortuosity on the sound absorption properties of the materials are studied. The distribution of sound pressure cloud images of porous materials at different frequencies is analyzed, and the variation law of sound absorption coefficient of porous materials at low frequency (0-1700 Hz) and its influencing factors are revealed. According to the above theory and calculation method, the acoustic calculation model of sandwich structure composed of porous materials and fiber reinforced composites is constructed, and the underwater acoustic characteristics of three different surface sandwich structures are studied. The influencing factors of underwater sound absorption performance of sandwich structure are analyzed. Finally, by adjusting the composite material parameters of the sandwich structure, the sound absorption coefficients of different sandwich structures under the vertical incidence sound wave are simulated and calculated. The effects of surface materials, sound absorbing core materials and sandwich structure on the sound absorption characteristics were studied, and the optimization scheme for improving the sound absorption coefficient of sandwich composite structures was given.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33

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