具有自相似结构的声学超材料板的带隙特性研究

发布时间：2017-12-28 20:02

  本文关键词：具有自相似结构的声学超材料板的带隙特性研究　出处：《哈尔滨工业大学》2016年硕士论文　论文类型：学位论文

  更多相关文章： 声学超材料 共振 带隙 自相似 声学

【摘要】：声学超材料是具有频率带隙的人工复合结构,它对一定频率的弹性波具有阻隔的作用,这使其在隔声降噪领域得到了广泛的研究。本文对声学超材料的带隙行为及声载荷响应进行了研究。在振动吸收器原理的基础上,通过理论分析和仿真计算,研究了局部共振声学超材料板胞元带隙的变化规律,建立了声学超材料板的质量弹簧分析模型,根据薄板弯曲振动理论给出了声学超材料板的振动控制方程,通过MATLAB编程计算得到了结构的色散关系,模态分析表明,反相位共振模态出现在带隙范围内,从而验证了结果的正确性。质量块和薄膜的初始变形量是结构的振动特性的主要影响因素,通过计算不同质量块质量和薄膜预载荷条件下结构的色散关系,发现质量块质量和初始变形量必须控制在合理的范围内才能在低频获得宽频带的带隙结构。进一步分析了无质量块声学超材料板中Bragg散射和局部共振两种带隙产生机理的转化条件,给出了相应的材料参数变化范围。考虑到质量块的存在有利于实现声学超材料板低频宽带带隙特性,基于自相似结构形状,提出了多质量环构成的自相似声学超材料板的设计方案,并验证了结构的带隙特征。结果表明,质量环的增加使得声学超材料板的带隙频带变宽,带隙的中心频率降低,带隙的个数增加,窄质量环比宽质量环更能获得宽频带隙。对自相似结构声振响应分析发现,第一次共振时质量块的位移远大于其它部位,此时的质量块在振动过程吸收大部分的能量;第二次共振时,质量块和边框的共振位移很小,内部环和膜振动消耗的能量增加;质量环的增加有利于结构能量的均匀分布。通过比较超材料板的透射声压和入射声压,给出了多组合板结构的传递函数。研究表明,组合数越多,传递函数绝对值越大;声学超材料板之间的距离对传递函数的影响类似于正弦函数变化规律;组合数和两板之间的距离只有在合适范围内传递函数才能取得较为理想的值,这为声学超材料板的隔声检测提供参考依据。
[Abstract]:Acoustic metamaterial is an artificial composite structure with frequency band gap. It has the function of blocking the elastic waves at a certain frequency, making it widely studied in the field of sound insulation and noise reduction. The band gap behavior and acoustic load response of acoustic supermaterials are studied in this paper. Based on the principle of vibration absorber, through theoretical analysis and simulation, changes of cell bandgap metamaterials in the local resonance acoustic research, established a quality spring acoustic metamaterial plate model, vibration control equation of acoustic metamaterial plate based on thin plate bending vibration theory is given, the dispersion relation of structure through the MATLAB programming calculation, modal analysis shows that the anti phase resonance modes in the band gap range, so as to verify the correctness of the results. The initial mass and the deformation of the film is the main influence factors of the vibration characteristics of the structure, through the dispersion relation calculation of different mass and film pre loading conditions, found that the mass and initial deformation must be controlled in a reasonable range can be obtained with wide band gap structure in low frequency. The transformation conditions of the two kinds of bandgap generation mechanism of Bragg scattering and local resonance in mass free bulk acoustic metamaterials are further analyzed, and the corresponding range of material parameters is given. Considering the existence of mass blocks, the low-frequency broadband bandgap characteristics of acoustic metamaterials are realized. Based on the shape of self similar structures, the design scheme of self similar acoustic metamaterials with multiple mass rings is proposed, and the band gap characteristics of the structures are verified. The results show that the increase of mass ring makes the band gap of acoustic metamaterials wider, the central frequency of band gap decreased, the number of band gaps increased, and the wide band gap of narrow mass ring wider mass ring can be obtained. The self similar structure of sound and vibration response analysis, the first resonance mass displacement is far greater than the other parts, the mass in the process of vibration absorb most of the energy; the second resonance, resonance mass displacement and border is very small, the internal energy ring and membrane vibration increased consumption; increase the quality of the ring beneficial to uniform distribution of energy structure. By comparing the transmission sound pressure and the incident sound pressure of the supermaterial plate, the transfer function of the multi composite plate structure is given. Research shows that the combination of the number, the greater the absolute value of the transfer function between the acoustic material board; ultra distance is similar to the sine function variation of the transfer function; between the number and the two in the distance is only in the appropriate range of transfer function can achieve the ideal value, to provide reference for the detection of ultra acoustic insulation a sheet of material.
【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】：2016
【分类号】：TB34
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本文编号：1347195