Flexural Wave Mainpulation Characteristics of a Periodic Plate with Embedded 2D Acoustic Black Holes
Acoustic Black Hole(ABH)structure can be achieved by tailoring the thickness of a structure according to a power function,thus altering the phase velocity of the flexural wave by changing the impedance and enabling energy focalization.The ABH provides a new idea for vibration and noise control in aerospace structures.The ABH array shows the potential to improve wave manipulation characteristics of the ABH design at the middle-low frequency.This paper focuses on studying the flexural wave propagation in a thin plate with embedded periodic two-dimensional(2D)acoustic black holes.The ABH that differs from the classical one proposed by Krylov is centrally with a platform and expected to obtain different wave manipulation properties when it is arranged in the square lattice.The band structure of an infinite periodic ABH plate and the structural intensity vector field in a finite plate with ABH lattice are scrutinized by establishing finite element models.The comparison of band structure results from finite element and plane wave expansion methods clarifies the convergence and applicable conditions of the plane wave expansion method.Numerical results show that the ABH with a central platform is easy to obtain a flat band representing local resonance at low frequency when it is arranged in the square lattice.Near or above the full-wavelength characteristic frequency of the 2D ABH,the square lattice consisting of the ABH with a central platform shows different wave energy direction propagation from the ABH without a central platform.Finally,the influence of ABH cross-section parameters on the band structure is analyzed.The results show that ABH profile parameters have less effect on band structure below the half-wavelength characteristic frequency.The reduction of the central truncation thickness,the increase of the central platform radius,and the power exponent larger than 2 are conducive to forming a broadband directional band gap.
ABHflexural wavesplane wave expansion methodfinite element analysislocal resonance
国家科技期刊平台
NSTL
万方数据
