薄膜声学超材料微结构特征对其隔声性能影响的研究
发布时间：2018-10-24 11:20
【摘要】：随着科技的发展,工业化进程加剧,人们生产生活中面临的噪声问题也越来越严峻,由于质量作用定律的限制,在对低频范围的阻隔噪声的技术要求已越来越高,现阶段技术手段已经不能满足要求,薄膜类型声学超材料应运而生。本文主要研究了由弹性薄膜、附加质量块构成的薄膜声学超材料的隔声性能,先从离散振动模型入手,对薄膜超材料的振动特性做了分析预测,然后通过薄膜超材料的振动特性以及传递损失方面的仿真来进一步研究结构特征对薄膜声学超材料隔声性能,最后采用了混合有限元-统计能量法对薄膜超材料的受模态控制的前两阶隔声低谷进行了优化的研究。首先,基于局域共振机理的薄膜声学超材料型复合材料的胞元弹簧质量块的自由度振动模型,数值计算的结果与薄膜质量块系统的有限元仿真和文献的结果比较,在共振和反相共振的模态振型上能够吻合。本文所建立的离散振动模型的特点是能够直观反映胞元的结构多个参数对薄膜声学超材料结构隔声特性的影响规律。其次,薄膜声学超材料的模态信息是结构的振动特性,是一项非常重要的研究.通过对薄膜超材料单个胞元结构的模态仿真分析,将模态结果特别是模态振型和前面的离散模型相对应,通过离散模型预测微结构特征对薄膜超材料的模态频率及振型的影响规律,来验证离散模型的方法是可行的。接着,通过声学波的传递原理来阐述,从原理上对隔声传递损失进行了解,再根据薄膜声学超材料的模态分析的基础上对其传递损失进行了仿真分析,分别讨论薄膜厚度、薄膜预应力和附加质量块重量对其传递损失的影响,接着,深入探讨薄膜声学超材料传递损失谷值对应频率和固有频率之间联系以及传递损失谷值、峰值对应频率下振型的分析。最后在前文模态贡献量基础上,对传递损失波谷对应的固有频率下阵型进行关键区域的识别,并在关键区域中添加附加质量块,经过仿真对比后,发现这样附加质量块的布置,对前两阶波谷对应频率下的传递损失有比较明显的改善。
[Abstract]:With the development of science and technology and the aggravation of industrialization, the noise problem that people face in production and life is becoming more and more serious. Because of the limitation of the law of mass action, the technical requirements of blocking noise in the low frequency range are becoming higher and higher. At present, the technical means can not meet the requirements, film type acoustical supermaterial emerges as the times require. In this paper, the sound insulation performance of thin film acoustic supermaterial composed of elastic film and additional mass block is studied. The vibration characteristics of thin film supermaterial are analyzed and forecasted from discrete vibration model. Then the vibration characteristics and transfer loss of thin film supermaterial are simulated to further study the sound insulation performance of thin film acoustic supermaterial with structural characteristics. At last, the hybrid finite-element statistical energy method is used to optimize the first two levels of sound insulation of thin film supermaterials under modal control. Firstly, based on the mechanism of local resonance, the vibration model of the cell spring mass block of thin film acoustic supermaterial composite is proposed. The numerical results are compared with the finite element simulation of the thin film mass block system and the results of literature. The mode modes of resonance and inverse resonance can coincide. The characteristic of the discrete vibration model established in this paper is that it can directly reflect the influence of several parameters of cell structure on the sound insulation characteristics of thin film acoustic supermaterial structure. Secondly, the modal information of thin film acoustic supermaterial is the vibration characteristic of structure, which is a very important research. Through the modal simulation analysis of a single cell structure with thin film supermaterial, the modal results, especially the modal modes, are corresponding to the discrete model in front. The method of discrete model is proved to be feasible by predicting the influence of microstructure characteristics on the mode frequency and mode shape of thin film supermaterial. Then, through the transmission principle of acoustic wave, the loss of sound insulation transmission is understood in principle, and then the transfer loss is simulated based on the modal analysis of thin film acoustic supermaterial, and the thickness of film is discussed, respectively. The influence of membrane prestress and additional mass on the transmission loss is discussed. Then, the relationship between the corresponding frequency and the natural frequency and the transmission loss valley value of the film acoustic metamaterials are discussed in depth. Analysis of modes at peak corresponding frequencies. Finally, on the basis of the previous modal contribution, the key region of the matrix corresponding to the natural frequency of the transmission loss trough is identified, and the additional mass block is added to the critical region. After simulation, the layout of the additional mass block is found. The transmission loss at the corresponding frequencies of the first two order troughs is obviously improved.
【学位授予单位】：福建农林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.2;TB34
[Abstract]:With the development of science and technology and the aggravation of industrialization, the noise problem that people face in production and life is becoming more and more serious. Because of the limitation of the law of mass action, the technical requirements of blocking noise in the low frequency range are becoming higher and higher. At present, the technical means can not meet the requirements, film type acoustical supermaterial emerges as the times require. In this paper, the sound insulation performance of thin film acoustic supermaterial composed of elastic film and additional mass block is studied. The vibration characteristics of thin film supermaterial are analyzed and forecasted from discrete vibration model. Then the vibration characteristics and transfer loss of thin film supermaterial are simulated to further study the sound insulation performance of thin film acoustic supermaterial with structural characteristics. At last, the hybrid finite-element statistical energy method is used to optimize the first two levels of sound insulation of thin film supermaterials under modal control. Firstly, based on the mechanism of local resonance, the vibration model of the cell spring mass block of thin film acoustic supermaterial composite is proposed. The numerical results are compared with the finite element simulation of the thin film mass block system and the results of literature. The mode modes of resonance and inverse resonance can coincide. The characteristic of the discrete vibration model established in this paper is that it can directly reflect the influence of several parameters of cell structure on the sound insulation characteristics of thin film acoustic supermaterial structure. Secondly, the modal information of thin film acoustic supermaterial is the vibration characteristic of structure, which is a very important research. Through the modal simulation analysis of a single cell structure with thin film supermaterial, the modal results, especially the modal modes, are corresponding to the discrete model in front. The method of discrete model is proved to be feasible by predicting the influence of microstructure characteristics on the mode frequency and mode shape of thin film supermaterial. Then, through the transmission principle of acoustic wave, the loss of sound insulation transmission is understood in principle, and then the transfer loss is simulated based on the modal analysis of thin film acoustic supermaterial, and the thickness of film is discussed, respectively. The influence of membrane prestress and additional mass on the transmission loss is discussed. Then, the relationship between the corresponding frequency and the natural frequency and the transmission loss valley value of the film acoustic metamaterials are discussed in depth. Analysis of modes at peak corresponding frequencies. Finally, on the basis of the previous modal contribution, the key region of the matrix corresponding to the natural frequency of the transmission loss trough is identified, and the additional mass block is added to the critical region. After simulation, the layout of the additional mass block is found. The transmission loss at the corresponding frequencies of the first two order troughs is obviously improved.
【学位授予单位】：福建农林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.2;TB34
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