周期声学黑洞结构弯曲波带隙与振动特性

作为一种被动型波操控结构,声学黑洞能对弯曲波起到较好聚集作用,再结合阻尼层能更好抑制结构振动波的传播。从声子晶体角度通过周期性排列构造一种声学黑洞结构与基体结合的一维声子晶体结构,选取合适的晶胞,采用有限元法对周期排列的声学黑洞结构弯曲波带隙特性进行研究,对比分析8周期声子晶体梁与等长度的恒定截面梁及周期楔形梁的振动位移传递函数,讨论黑洞区域材料变化对带隙的影响。结果表明:该声学黑洞结构具有较好弯曲波带隙,在对应带隙及附近频带区间振动位移响应出现较大衰减,表明其抑制振动效果明显;在黑洞区域选择合适的材料可以使带隙向低频移动,同时使得带隙区间增多。

Band Gap and Vibration Characteristics of FlexuralWaves with Periodic Acoustic Black Hole Structure

As a passive wave control structure,acoustic black hole(ABH)with damping layers can well suppress the propagation of structural vibration waves.From the perspective of phononic crystals,a one-dimensional phononic crystal structure combining with ABH through periodic arrangement was studied.The finite element method was used to solve the band gap of the flexural waves.Vibration displacement transmission function of eight-cycle acoustic black hole beam,constant-length and constant-section beam and periodic wedge beam were compared and analyzed.And the effect of material change on the band gap in the black hole region was studied.The results show that the acoustic black hole beam can obtain a wide flexural wave band gap.Vibration displacement response in the band gap and nearby frequency bands attenuates greatly,which indicates that the effect of vibration suppression is obvious.Choosing the appropriate black hole material can make the band gap move to low frequency side and increase the number of the band gaps.