Study On Coupling Modeling And Structural Topology Optimization Method Of Local Resonance Piezoelectric Metamaterial Vibration Energy Capture System

Structural health monitoring is a key technology to improve the safety of major engineering structures and reduce maintenance costs.The wireless sensor network based on MEMS has become an important development direction of major engineering structure health monitoring technology because it is suitable for embedded in the structure to complete online monitoring.And how to provide long-term reliable power for low-power wireless sensors is a bottleneck.The thin plate structure is a common structural form,which often produces obvious vibration during operation.The piezoelectric effect can be used to convert the vibration into electrical energy to realize the self-power supply of the wireless sensor.Since the structural vibration is often unoriented and its energy is mostly in the form of elastic waves,and has the characteristics of broadband,low frequency,etc.,it is necessary to combine the elastic waves characteristics with the piezoelectric energy-capturing structure to improve the vibration energy of the broadband low-frequency environment.Capture efficiency.Under the auspices of the National Natural Science Foundation of China(Grant No.51577189),the paper constructs a piezoelectric metamaterial captive structure by arranging resonant elements composed of piezoelectric materials and masses onto a thin plate structure,using localized The resonance principle regulates the vibration transmission behavior on the thin plate,so that the vibration energy capture efficiency can be improved.The key issue is how to optimize the system.Therefore,for the local resonant piezoelectric metamaterial sheet,the theoretical model of the system is established based on the Kirchhoff sheet assumption,the Hamilton principle,the piezoelectric effect,etc.,and the synchronization is derived according to the Kirchhoff current(voltage)law.The equivalent impedance model of the charge extraction circuit is used to optimize the structure and circuit parameters,and the simulation calculation and experimental verification are carried out.The main work of the thesis includes:1.The theoretical model of multi-physics coupling of local resonant piezoelectric ultra-material thin plates is established.The transfer behavior of elastic waves in thin plates is analyzed.The system-wide coupling theory model is established and the piezoelectric model is drawn by finite element simulation software COMSOL.The dispersion curve of the metamaterial lattice is designed to satisfy the band gap condition of the lattice structure,so that the band gap range falls as far as possible in the target frequency range,achieving efficient energy capture.2.The equivalent impedance model of the synchronous charge extraction circuit(SECE)is derived by using Kirchhoff’s current(voltage)law,and the amplitude of the circuit’s captive voltage is effectively improved by external inductance and improved switching circuit,and theoretical analysis is carried out.And simulation verification,the results show that when the SECE circuit is connected to the external inductor,the amplitude of the output voltage can be effectively improved,and the theory of the energy absorption efficiency is improved,which is basically consistent with the simulation results.3.Using the finite element software COMSOL to verify the existence of the band gap in the finite structure,it can be found that in the band gap range,the vibration frequency response transfer function has a significant attenuation with the increase of the cycle number;and when the piezoelectric piece is connected with the resonant inductor,it can be effective.The amplitude of the output voltage is increased,and when the inductance value of the external inductor deviates from the resonant inductance value,the open circuit voltage outputted across the piezoelectric chip is significantly reduced.4.The experimental platform was designed and constructed.The vibration response function of the piezoelectric super-material thin plate under the finite periodic structure was tested to verify the existence of the band gap,which is basically consistent with the simulation results.The piezoelectric capture circuit test platform was built and tested separately.The capture voltage amplitude before and after the SECE circuit optimization shows that the optimized SECE circuit can effectively improve the energy capture efficiency.