周期结构细直梁弯曲振动中的振动带隙

通过将声子晶体中的周期结构思想引入到细直梁的结构设计中,构造了一种二组元变截面周期结构细直梁。采用平面波展开法计算了无限周期条件下该细直梁弯曲振动中的弹性波能带结构。计算结果表明,在该细直梁中存在振动带隙。晶格尺寸、材料组分比、截面尺寸对振动带隙的影响也进行了讨论。采用有限元法计算了有限周期的细直梁的振动传输特性,计算得到的振动传输特性曲线上的频率衰减范围与平面波计算得到的带隙位置基本吻合。最后以有机玻璃及铝构成的细直梁为例,采用振动试验对其振动传输特性进行了测试。试验结果同理论计算及仿真结果基本吻合。梁类结构是噪声及振动控制领域研究的主要对象之一,周期结构细直梁中存在弯曲振动带隙为梁类结构的减振提供了一种新的思路。

ELASTIC WAVE BAND GAPS IN FLEXURAL VIBRATIONS OF STRAIGHT BEAMS

The flexural vibration behavior of elastic wave across periodic binary inconstant section beam is studied by using plane-wave expansion (PWE) method and finite element (FE) method. Elastic wave band gaps are found in band structures of this kind of beam calculated with PWE method. The frequency ranges of sharp drop in frequency response curve simulated with FE method show good agreement with the band gaps. Those conclusions are verified by vibration experiment of periodic binary inconstant section beam consists of Al and organic glass. The existence of band gaps in these periodic structures gives a new idea in flexural vibration isolation of beams.