Design And Experimental Study Of High Amplitude Low Frequency Broadband Acoustic Energy Harvester

The main power supply for MEMS and wireless sensors is the battery,which has the disadvantage of the limited life span and high maintenance and replacement cost in complex areas.Through the energy harvester,the energy supply of the electronic device can be realized and the extended energy demand can be alleviated.Sound energy is a new energy with great potential and is widely found in the environment.The collection of sound energy can not only meet the needs of low-energy microelectronic devices,but also control noise.Sound energy is a new energy source that is energy efficient and environmentally friendly.However,the energy density of acoustic energy is extremely low and the frequency composition is complex.Therefore,it is necessary to perform wide-band sound pressure gain on incident sound waves to meet the needs.In this paper,two broadband acoustic energy harvesting based on Helmholtz resonators with double cavities and film acoustic metamaterials with double defects are proposed to realize broadband sound pressure gain and acousto-electro-mechanical conversion for incident sound waves.The main research content of this paper is divided into three parts:(1)A broadband acoustic energy harvesting based on Helmholtz resonator is proposed.The dual-frequency sound pressure gain of Helmholtz resonator with double cavities and nonlinear energy acquisition systems are used to realize the harvesting of broadband acoustic energy.The theoretical model of the system is established,and the frequencies of the two are matched by numerical calculation and simulation analysis.A test bench was built to investigate the output response characteristics of nonlinear elements to the energy harvester system.The influence of the matching relationship between Helmholtz resonator and nonlinear system on the output response characteristics of the energy harvester system is explored.The optimum power of the acoustic energy harvesting is obtained by load adaptation.(2)A design method of the film acoustic metamaterial with double defects is proposed.The flapping resonance of the system is induced by the symmetry breaking method and coupled with the inherent monopolar resonance of the system to form a double negative acoustic metamaterial.The influence of symmetry breaking on the vibration mode characteristics is explored.The defect of the acoustic supermaterial is constructed by changing the local near-field effect of the structure by introducing defect resonator.A design method for film acousticmetamaterials with double defect is proposed.The energy band structure and surface vibration characteristics are calculated by simulation,and the basic characteristics are explored to optimize the structure.A test bench was set up to test and verify the surface vibration of the film acoustic metamaterial.(3)A broadband acoustic energy harvester based on acoustic metamaterial with double defects is proposed,which connects the acoustic metamaterial and the piezoelectric transducer through nonlinear magnetic force.The test bench was built,the response characteristics of the acoustic energy harvester at the defect frequency were studied,the response gain characteristics of the defect were studied,the influence of magnetic action on the response characteristics of the acoustic energy harvester was studies,and the sweep response characteristics of the acoustic energy harvester was studies.