The Energy Harvesting And The Nonlinear Dynamics Research Of The L-shaped Piezoelectric Cantilever Beam

In recent years,with the development of microelectronics technology and wireless technology,handheld electronic devices and wireless sensor entered the era of small,low power consumption.Traditional battery is no longer a need to apply to the equipment,which requires us to explore efficient self-powered systems.Vibration energy is the most common kind of energy in the environment.The vibration in the environment is everywhere,and it is very important to take advantage of it.The vibration energy acquisition technology based on piezoelectric effect has attracted much attention in recent years,as a bright spot in the new energy field.Piezoelectric vibration energy collector has the advantages of simple structure,high energy density,long life and so on.It has a wide application prospect in the self-powered system.In this paper,the piezoelectric energy collector of the L-shaped cantilever beam is used as the research object to analyze its power generation effect and nonlinear dynamic characteristics.In this paper,the structure of L-shaped piezoelectric cantilever beam is studied.And the power generation capacity is analyzed by comparing the power generation capacity of L-shaped piezoelectric cantilever beam and the straight beam with mass block in the end.We also study the influence of various parameters on power generation capacity of L-shaped piezoelectric cantilever.Furthermore,the structure of L-shaped piezoelectric cantilever beam is optimized,and the structure of bistable inverted L-shaped piezoelectric cantilever is finally obtained.We analyze the influence of various factors on the power generation performance of the bistable inverted L-shaped piezoelectric cantilever.Comparing the power generation effect and dynamic response of bistable inverted L-shaped piezoelectric cantilever beam and traditional bistable straight beam,we analyze the power generation advantage of bistable inverted L-shaped beam.We further study the nonlinear dynamics of bistable inverted L-shaped beam.The dynamical equations of the bistable inverted L-shaped piezoelectric cantilever beam are derived,the numerical analysis are analyzed,and its power generation characteristics and dynamic characteristics are researched.The main research contents of this paper are divided into the following parts:(1)The influence of various parameters on the power generation capacity of L-shaped piezoelectric cantilever beam is studied by comparing the power generation capacity of L-shaped piezoelectric cantilever beam and the straight beam with mass block in the end.A series of L-shaped beam's optimization models are designed to obtain the optimal structure,that is the bistable inverted L-shaped beam structure.Further study the influence of external excitation amplitude,external excitation frequency,self-size and magnetic spacing on the power generation capacity of thesystem.(2)Compare and study the bistable inverted L-shaped piezoelectric cantilever beam and the traditional bistable straight beam,we also establish the magnetic model which forms bistable mechanism.In this paper,we mainly compare the power generation characteristics and dynamic response of two bistable structures,and analyze the power generation advantage of bistable inverted L-shaped beam.(3)The nonlinear dynamics of bistable inverted L-shaped beam is researched.The nonlinear characteristics of the system are studied mainly from three aspects,namely,bistable characteristics,stiffness characteristics and complex dynamic behaviors.Firstly,the bistable characteristics of the system are explained by experiments.Then the jumping phenomenon of the system is studied by the positive and inverse sweep frequency of the voltage and displacement,which is the stiffness characteristic of the system.Finally,the influence of different factors on the dynamic behavior of the system is mainly studied.In addition,we study the relationship between dynamic behavior and electrical behavior,also the influence of magnetic spacing and external excitation amplitude on chaotic dynamics and electrical behavior of the system.(4)The dynamic equation of inverted bistable L-shaped beam is established through Lagrange equation.Numerical method is used to study the periodic motion and chaotic motion of bistable inverted L-shaped beam structure,the influence of different parameters on system dynamic response and piezoelectric power generation,then analyze and compare with the experimental results.