可用于隔声和带隙调控的五模式超材料

Pentamode metamaterials used for sound insulation and band gap controlling consisting of double-cones

为了利用在声学领域极具应用前景的双锥型五模式超材料进行隔声降噪,提出一种双锥宽直径不全同型五模式超材料.利用有限元方法分析了其声子能带结构、各波模相速度、品质因数随结构与材料参数的变化关系,在实用性和稳定性上与窄直径不同型五模式超材料作了比较.宽直径不全同型五模式超材料在保持原始五模式结构单模传输能带的前提下,还产生了更低频、宽带的三维完全带隙,且结构更稳定,重量更轻。双锥型五模式超材料在特定宽直径不同时具有三维完全带隙,品质因数主要由结构参数决定,各材料参数只是不同程度地影响带隙的绝对宽度和位置.研究结果表明双锥宽直径不全同型五模式超材料有望用于带隙调控和隔声。

In order to effectively insulating or reducing the noise underwater by utilizing the pentamode metamaterials composed of double-cone units which is of great application prospects in the field of acoustics, here a kind of pentamode metamaterial made of the double-cone units with different wide touch diameters was proposed. The phononic band structure, the phase velocities of compression and shear modes and the figure of merit were numerically calculated by using finite element method, and then the influences caused by constituent material parameters and geometric structure parameters were analyzed systematically. Results indicated that the pentamode metamaterial proposed right here obtained a wider, lower-frequency phononic band gap, better stability and lighter weight compared with pentamode metamaterial made of the double-cone with different narrow touch diameters which was reported previously, under the premise that the original pentamode structure＇s single mode region was still remained even if a certain wide touch diameter individually changing. Consequently, a relatively wide and low-frequency band gap appeared while the particular wide touch diameters individually changing. The figure of merit was mainly determined by the geometric structure parameters. Each constituent material parameters only affects the bandwidth and location in different ways. Therefore, pentamode metamaterial made of the double-cone units with different wide touch diameters is expected to be used for underwater acoustic noise reduction or controlling the phononic band gaps.