Wideband Vibration Energy Harvesting:A Study On The Structure Of Bi-stable Generator Array With Coupling Effects

Due to the bright prospect of fit with intelligent society,wireless sensor network has been developing rapidly with the efforts of a large number of researchers.It has been widely used in medical health,structural monitoring and diagnosis,industrial and agricultural production,intelligent transportation and other fields.In order to overcome the disadvantages of traditional battery power supply,energy harvesting has received much attention.As an important research frontier and hot spot in the field of energy harvesting research,vibration energy harvesting has the characteristics of relatively large energy density and wide distribution.In order to capture as much mechanical energy as possible from environmental vibration,many researchers have proposed the method of wideband vibration energy harvesting,which has stronger adaptability and can provide relatively good and stable power harvesting output in different incentive conditions.In this paper,the bi-stable wideband vibration energy harvesting structure is innovated.A bi-stable generator structure with elastic support is proposed,and the dynamic equation of the system is established.The proposed structure is studied and analyzed by means of numerical analysis and experimental verification.The main research work and conclusions of this thesis are as follows:(1)The structure of array bi-stable piezoelectric post-buckling beam and its simple aggregate model are discussed,and modeling and simulation are carried out.The piezoelectric post-Buckling beam generator has the advantages of wide bandwidth,small size,and easy to implement.However,it is very complicated to establish the conventional multi-mode model and it is difficult to optimize and design the generator.The simple aggregate model proposed in this paper clarifies the relationship between the parameters of the piezoelectric beam and the model variables,greatly simplifies the optimization process,and enables the optimization of the piezoelectric post Buckling beam generator to be realized.The numerical results show that in a certain range of normalized buckling,the effectiveness of the proposed method is proved by static and dynamic evaluation.This shows that the proposed aggregate model has a good interchangeability,especially in the case of a low dimensionless buckling level.This conclusion can provide great convenience for the design of piezoelectric post-buckling beam,and it can be further extended.The application range of the approximate model,it is widely used in the design and optimization of the post-generator.(2)The structure of an array double stable beam with elastic coupling is proposed and discussed,a dynamic model is established and a numerical analysis is carried out.The proposed structure is designed to further enhance the performance of the dual stable beam.This structure consists of two Buckling beam generators.More importantly,elastic coupling is introduced between the two generators to further enhance the dynamic response of the system and increase the power of the entire generator.The numerical simulation results show that the elastic coupling can be reasonably introduced and the performance can be improved.However,when the elastic coupling is strong,because the vibration States of the two generator structures in the array are not the same,they will affect each other by coupling,making them unable to maintain stable high-energy orbits,and the performance will be drastically weakened.Therefore,the application of elastic coupling boundary conditions is limited,and it is necessary to pay special attention to the strength of the coupling level.(3)An optimized structure is proposed based on the structure of an array with elastic coupling and a bi-stable Buckling beam(hereinafter referred to as DBB-TTC).In the study,we found that the simultaneous introduction of flat coupling and torsional coupling between two generators can achieve a certain range of synchronization mechanisms between the collectors so that they do not destroy each other’s high-energy orbits.The biggest feature of the DBB-TTC generator is that the introduction of translation and torsion coupling between two generators through common elastic supports.The mechanism of synchronous double buckling beam dynamics is provided.Experiments and theoretical studies show that the proposed DBB-TTC generator has obviously improved the power performance and bandwidth of harmonic or noise excitation.