基于高斯展开法的周期声学黑洞宽频能量回收特性研究

The acoustic black hole (ABH) effect is a phenomenon in which the thickness of the beam or thin plate structure is tailored according to the power law, so that the bending wave speed at the tip of the structure is reduced to zero without reflection and then the energy accumulation and efficient recovery can be realized at the end of the structure. Aiming at the problem that the structure of a single acoustic black hole is sensitive to external excitation frequency when achieving peak recovery, a broadband piezoelectric energy recovery system based on periodic acoustic black holes was proposed. Based on the Gaussian expansion method, a semi-analytical model of the acoustic black hole piezoelectric energy trapping with coupled piezoelectric layers was established, and in frequency domain referring to the energy band theory, the effects of period number, power exponent, central cut-off thickness, and black hole radius on energy recovery were analyzed. A piezoelectric energy recovery experiment verified the effectiveness of periodic acoustic black holes for achieving broadband energy recovery. The results show that adjusting the structural parameters of acoustic black holes can affect such factors as the number of peaks, the length of the peak interval, and the energy band structure so as to improve the output power and collection efficiency of the system. The analysis results have important reference value for realizing the optimal design of broadband energy recovery of periodic acoustic black hole beams.