Research On Energy Focalization And Capture Technology Of Two-Dimensional Acoustic Black Hole Flat Structure

Acoustic black hole(ABH)effect is to tailor the thickness of the structure in the wave propagation direction to make its thickness profile curve or surface meet a specific power law,thereby achieving efficient passive control of elastic waves.The two-dimensional acoustic black hole depression embedded in the rectangular plate structure can reduce the propagation speed of the elastic wave entering the black hole area and gather it at a specific position.Ideally,all elastic waves are captured by the black hole area,and no emission phenomenon will occur.This kind of passive control technology for elastic waves by changing the thickness of the structure and affecting the structure impedance has the characteristics of wide frequency,high efficiency and easy implementation.It has broad application prospects in the fields of vibration and noise control and energy capture,so it has important theoretical research.And application value.In practice,a non-ideal two-dimensional acoustic black hole structure that also has an acoustic black hole effect is usually used.This structure usually has a hole or a circular platform in the center of the black hole.In this paper,the non-ideal two-dimensional acoustic black hole rectangular plate structure with the center of the black hole area as the research object is studied by finite element numerical simulation,etc.on the propagation of the bending wave,energy concentration characteristics and vibration energy capture performance in the structure.Research,specific research content is as follows:(1)A parametric model of a non-ideal two-dimensional acoustic black hole rectangular plate structure is established.Combined with the geometric acoustic approximation theory,the trend of the thickness,contour and surface of the black hole area in the structure is analyzed as some important parameters that determine its geometric configuration change,And the impact on the refractive index of the area.(2)A numerical simulation model of a single ABH rectangular plate structure is established in ABAQUS software,and the propagation process of bending waves in the time domain and the energy distribution in the structure under transient excitation conditions are studied.The geometric parameters,such as the energy concentration characteristics of the structure with different geometric configurations when the center circular table radius,circular table thickness and power law index change,and the energy distribution in a rectangular flat plate structure with multiple acoustic black hole depressions were studied.(3)Combining a single ABH rectangular plate with a piezoelectric sheet microarray,considering the wavelength compression characteristics and piezoelectric effect of the acoustic black hole area,the acoustic black hole piezoelectric sheet coupling plate structure for vibration energy capture was designed and established in COMSOL software Electromechanical coupling model.The time-domain energy capture performance of the electromechanical coupling model under broadband excitation was studied,and the steady-state energy capture performance of the model was analyzed in the frequency domain,which confirmed the positive effect of the presence of the acoustic black hole structure on the vibration energy capture effect of the coupled structure.