三角晶格固/气型声子晶体的弹性波带隙结构

Elastic Wave Band Gap Structures of Triangular Lattice Phononic Crystal with Solid/Air System

将椭圆钢柱散射体引入到三角晶格固/气型声子晶体中,用平面波法计算了其带隙结构。研究表明,通过降低散射体横截面的对称度,可在几乎不改变带隙中心频率的条件下获得更宽的低频带隙,还能在极低的填充率下实现低频带隙。随着填充率的增大,带隙变宽,中心频率下降。当散射体绕其中心轴的旋转角度小于60°时,带隙宽度随旋转角度的增大而减小,但带隙中心频率基本不受影响。

The plane wave expansion method is employed to calculate the band gap structures of triangular lattice phononic crystal composed of elliptical steel cylinders embedded in air matrix. It is concluded that the wider low band gap with nearly the same mid-gap frequency and the low band gap appearing at little filling fraction can be obtained by reducing the symmetry of elliptical cylinders＇ cross section shape. Moreover, the width of band gap increases and the mid-gap frequency declines as the filling fraction increases. By adjusting the scatters＇ rotation angle from 0° to 60°, the narrower band gap can be achieved, but the mid-gap frequency nearly keeps unchanged.