磁流变弹性体调控的声子晶体波传播研究

发布时间：2018-06-28 03:06

本文选题：磁流变弹性体 + 声子晶体　；参考：《宁波大学》2017年硕士论文

【摘要】：自从声子晶体的概念被提出后,由于其独特的物理性质和广阔的应用前景,声子晶体的相关研究很快成为一个热门的研究课题。声子晶体的一个显著特点就是存在完全带隙(ABG),在带隙范围内的声波无法在其中传播。基于这一特点,声子晶体可广泛应用于减震、降噪、滤波等领域。磁流变弹性体(MRE)是一种新型智能材料,由聚合物基体与微米级的铁磁性颗粒组成,它的物理性质可以通过磁场来调控,当施加外部磁场时它的弹性模量明显增加。本文主要研究由MRE和PMMA制成声子晶体的带隙特性,探究模量对声子晶体带隙的影响。论文的主要工作有:(1)筛选合适的基体、添加剂与铁磁性颗粒,通过预结构化和非预结构化的方法制备了各向同性与各向异性两种磁流变弹性体。采用DMA和MCR流变仪对制备的样品进行测试分析,通过对储能、损耗模量和损耗因子等参数的研究,发现各向异性磁流变弹性体在0.8T磁场下磁流变性能达到最好。(2)研究了由MRE和PMMA两种材料周期性排列而组成的一维声子晶体中波的传播。在实验阶段,用高斯计来确定磁场大小,LMS处理实验数据得到带隙,记录不同磁场下一维声子晶体的带隙,并与采用Comsol软件计算的结果进行比较。发现了声子晶体中波的传播可以通过调节MRE的模量来改变,即可以通过改变磁场强度来调节一维声子晶体的带隙。(3)对一种局域共振型人工周期梁结构进行了研究,这种三层梁结构中的弹簧由磁流变弹性体替代,基体梁和悬臂梁式振子选用对磁场无响应的亚克力板。一方面通过实验改变磁场测量其频响曲线,另一方面用有限元Comsol软件计算其振动模态和带隙变化,探究磁场对局域共振型人工周期梁结构的带隙影响。
[Abstract]:Since the concept of phonon crystal was put forward, due to its unique physical properties and wide application prospects, the research of phonon crystal has quickly become a hot research topic. A prominent feature of phononic crystals is the existence of a complete band gap (ABG) in which sound waves in the band gap range cannot propagate. Based on this feature, phonon crystals can be widely used in shock absorption, noise reduction, filtering and other fields. Magnetic rheological elastomer (MRE) is a new type of smart material, which consists of polymer matrix and ferromagnetic particles of micron size. Its physical properties can be controlled by magnetic field, and its modulus of elasticity increases obviously when external magnetic field is applied. In this paper, the band gap characteristics of phononic crystals made from MRE and PMMA are studied, and the influence of moduli on band gaps of phononic crystals is investigated. The main work of this paper is as follows: (1) selecting suitable matrix, additives and ferromagnetic particles, two kinds of magneto-rheological elastomers, isotropic and anisotropic, were prepared by pre-structured and unstructured methods. DMA and MCR rheometer were used to test and analyze the samples, and the parameters such as energy storage, loss modulus and loss factor were studied. It is found that the magneto-rheological properties of anisotropic magneto-rheological elastomers are the best in 0.8T magnetic field. (2) the propagation of waves in one-dimensional phononic crystals composed of two kinds of materials (MRE and PMMA) is studied. In the experiment stage, the magnetic field size is determined by Gao Si and the band gap is obtained by processing the experimental data. The band gap of one dimensional phonon crystal under different magnetic fields is recorded and compared with the results calculated by Comsol software. It is found that the propagation of waves in phononic crystals can be changed by adjusting the modulus of MRE, that is, the band gap of one-dimensional phononic crystals can be adjusted by changing the magnetic field intensity. (3) A kind of locally resonant artificial periodic beam structure is studied. The spring in the three-layer beam structure is replaced by the magneto-rheological elastomer, and the matrix beam and cantilever beam vibrator are composed of acrylic plates which have no response to the magnetic field. On the one hand, the frequency response curve is measured by changing the magnetic field experimentally; on the other hand, the vibration mode and band gap change are calculated by the finite element Comsol software, and the influence of magnetic field on the band gap of the local resonant artificial periodic beam structure is investigated.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O735

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