可变形声学超材料板的减振性能研究

发布时间：2018-01-27 02:51

  本文关键词： 声学超材料板 粘弹性 可变形 带隙 减振 振动实验　出处：《哈尔滨工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：声学超材料是近些年出现的一种周期性人工复合结构,在某些特殊频段会出现负的等效参数,这些频段被称为带隙。带隙的存在使得声学超材料在低频降噪方面相比于传统的隔音材料具备明显优势,但也存在带隙的范围较窄的问题。在声学超材料的发展过程中,声学超材料板由于其轻质、可承载、易于得到负等效参数的特点受到了广泛关注,并在近些年得到了很大发展,但带隙范围窄的问题依然存在。本文提出了一种可变形声学超材料板的方案,研究如何利用质量块变形来拓宽声学超材料板的频率带隙,并探究带隙与其减振性能之间的联系,这对于推动薄膜型声学超材料在减振领域的发展和应用具有重要意义。首先,使用有限元软件分别对质量块变形前、后的声学超材料板进行能带结构和振动传输损耗的仿真计算,发现质量块的变形可以使带隙的位置和宽度发生偏移,且声学超材料板对频率处于带隙范围内的振动具有较强的衰减能力,频率带隙和减振性能之间存在对应关系。进一步分析橡胶薄膜的预拉伸量、质量块的附着面积对于声学超材料板带隙位置和宽度的影响,根据变化规律对方案进行改进、优化。然后,使用分数阶Kelvin-Voigt模型对橡胶的粘弹性本构模型进行描述,将橡胶薄膜视为粘弹性矩形板对其振动方程进行推导,获得了振动方程的解析解。通过动态频率扫描实验,发现橡胶薄膜弹性模量会随振动频率的增长而变大,并根据实验数据对声学超材料板的能带结构进行了仿真分析,发现随着薄膜弹性模量的增大,带隙出现的位置会变高,带隙宽度会先变大后变小。最后,根据设计方案制作了两个声学超材料板来模拟质量块变形前后的状态,进行了振动实验,获得了相应的频率响应曲线。实验结果对比表明,质量块变形后的减振能力强于质量块变形前的状态,且都能对频率处于带隙范围内的振动进行较强的衰减。
[Abstract]:Acoustic supermaterial is a kind of periodic artificial composite structure which appears in recent years and has negative equivalent parameters in some special frequency bands. These bands are called band gaps. The existence of band gaps makes acoustic supermaterials have obvious advantages over traditional acoustic insulation materials in low-frequency noise reduction. However, there is also a narrow band gap. In the development of acoustic metamaterials, the characteristics of acoustic metamaterials are easy to get negative equivalent parameters due to their lightweight, load-bearing. In recent years, great progress has been made, but the problem of narrow band gap still exists. In this paper, a deformable acoustic supermaterial plate scheme is proposed. This paper studies how to use mass block deformation to widen the frequency band gap of acoustic metamaterials and to explore the relationship between the band gap and its vibration absorption performance. It is of great significance to promote the development and application of thin film acoustic supermaterials in the field of vibration absorption. Firstly, the finite element software is used to deform the mass blocks. The energy band structure and vibration transmission loss of the acoustic supermaterial plate are simulated and calculated. It is found that the deformation of the mass block can offset the position and width of the band gap. The acoustic supermaterial plate has a strong attenuation ability to the vibration in the frequency band gap range, and there is a corresponding relationship between the frequency band gap and the vibration absorption performance. The influence of the attachment area of the mass block on the position and width of the band gap of the acoustic supermaterial plate is improved and optimized according to the changing law. The viscoelastic constitutive model of rubber is described by fractional Kelvin-Voigt model, and the vibration equation of rubber film is deduced as a viscoelastic rectangular plate. The analytical solution of the vibration equation is obtained. Through the dynamic frequency scanning experiment, it is found that the elastic modulus of the rubber film increases with the increase of the vibration frequency. According to the experimental data, the band structure of the acoustic supermaterial plate is simulated and analyzed. It is found that with the increase of the elastic modulus of the film, the position of the band gap will become higher, and the width of the band gap will first become larger and then smaller. Finally. According to the design, two acoustic supermaterial plates are made to simulate the state of mass blocks before and after deformation. The vibration experiments are carried out and the corresponding frequency response curves are obtained. The damping capacity of mass blocks after deformation is stronger than that of mass blocks before deformation, and both of them can attenuate the vibration in the band gap range.
【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】：TB535.1;TB33
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本文编号：1467357