Two-Dimensional Eulerian-Exponential-Law Acoustic Black Hole Structure for Energy Harvesting

Thin plates are widely used in engineering, so it is of great value to explore energy harvester based on this type of structure. Acoustic black hole (ABH) is helpful for the energy harvesting of thin plate. However, the traditional power-law ABH needs to be improved in the low-frequency energy harvesting. Thereupon, a new Eulerian exponential law for ABH is proposed, and a 2-D ABH structure based on the Eulerian exponential law is designed for harvesting low-frequency energy. This article constructs a simple electromechanical coupling dynamic model for the Eulerian-exponential-law ABH energy harvester (EAEH). This model has low computation complexity as the dimension of thin plate is reduced by the Kronecker product of x- and y-direction beams' modes. Combining the element division and modal analysis of beam, a new method with high computational efficiency is proposed for calculating the base functions of thin plate with 2-D ABH, and its effectiveness and accuracy are validated by the result of finite-element analysis. Under different excitation frequencies, the voltage and power responses of EAEH are simulated, and their validity is verified by the experimental results. Moreover, EAEH is compared with the power-law ABH energy harvester through the simulation and experiment. The comparative results show that EAEH has lower resonant frequencies and higher output of voltage and power.