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本文提出了一种新型局域共振复合单元声子晶体结构,并结合有限元方法对结构的带隙机理及低频共振带隙特性进行了分析和研究.共振带隙产生的频率位置由所对应的局域共振模态的固有频率决定,并且带隙宽度与局域共振模态的品质因子及其与基体之间的耦合作用强度有关.采用局域共振复合单元结构可以实现声子晶体的多重共振,在低频范围能打开多条共振带隙,但受到共振单元排列方式的的影响.由于纵向和横向局域共振模态的简并,复合单元结构能在200Hz以下的低频范围打开超过60%宽度的共振带隙,最低带隙频率低至18Hz.这为声子晶体结构获得低频、超低频带隙提供了一种有效的方法.
In this paper, a new type of local resonant composite unit phononic crystal structure is proposed, and the bandgap mechanism of the structure and the band gap characteristics of low frequency resonance are analyzed and studied in combination with the finite element method.The frequency position of the resonance bandgap generated by the corresponding The local frequency of the local resonance mode is determined, and the band gap width is related to the quality factor of the local resonance mode and the intensity of the coupling effect between the two. By using the local resonance composite unit structure, the multiple resonance of phononic crystals , Can open multiple resonant bandgaps in the low frequency range but is affected by the arrangement of the resonating elements Due to the degeneracy of the longitudinal and transverse local resonance modes the composite cell structure can open over 60% of its width in the low frequency range below 200 Hz The lowest bandgap frequency is as low as 18Hz, which provides an effective method for obtaining low frequency and ultra-low bandgap in phononic crystal structure.