基于椭圆散射体的二维三角晶格声子晶体带隙

采用降低对称性改变带隙宽度及位置的思想,以椭圆柱体代替圆柱体构成二维三角晶格钢/空气声子晶体,利用平面波展开法计算其能带结构.结果表明,由于采用椭圆柱体降低了散射体的对称性,从而打开一条新的低频带隙,并且在一定的填充率范围内获得更宽的带隙.此外,散射体截面越接近于圆越容易打开高频带隙;反之,散射体的椭圆截面越扁,越利于打开低频带隙.该研究为声子晶体在低频减振和噪音控制的工程应用方面提供了一种思路.

Acoustic Band Gaps on Two-dimensional Triangular Lattice Phononic Crystal With Elliptical Cylinders

Using the symmetry reduction method,elliptical steel cylinders are periodically arrayed in air,which forms the two-dimensional triangular lattice phononic crystal.The band structures are computed by the plane wave expansion(PWE) method.Numerical results show that the degeneracy at high symmetry point of Brillouin zone can be lifted by using elliptical scatters,which lowers the frequency for opening band gaps.Besides,the lower symmetry is,the easier it is to open wide low frequency band gaps.In contrast,the higher it is,the easier it is to open wide high frequency band gaps.These results can be used in industrial design to isolate low frequency noise.