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以准周期Fibonacci序列为基础,构建了准周期镜像对称结构的一维固液介质声子晶体。利用转移矩阵法,研究了弹性波在所构建的声子晶体中的透射特性。结果表明:弹性波正入射时,转移矩阵与变介质的特性阻抗有关,由于声子晶体结构的局域失谐,在透射谱的中心频率附近对称出现谐振模;对于Q7序列的声子晶体,带隙内谐振模带宽小于10Hz,能实现超窄带声滤波;弹性波斜入射时,带隙向高频区移动;入射角为5°时,谐振模也向高频移动;入射角为10°时,由于谐振的增强,声子晶体结构对频率的选择性提高,使带隙内的谐振模消失。
Based on the quasi-periodic Fibonacci sequence, a one-dimensional solid-liquid media phononic crystal with quasi-periodic mirror symmetry structure is constructed. Using the transfer matrix method, the transmission characteristics of elastic waves in the phononic crystals are studied. The results show that the transfer matrix is related to the characteristic impedance of the variable medium when the elastic wave is incident. Due to the local mismatch of the phonon crystal structure, the resonant mode appears symmetrically around the central frequency of the transmission spectrum. For the phonon crystal of Q7 series, When the incident angle is 5 °, the resonant mode also moves toward the high frequency. The incident angle is 10 ° , The selectivity of the phonon crystal structure to the frequency is increased due to the enhancement of the resonance, so that the resonance mode in the band gap disappears.