Research On Piezoelectric Track Vibration Energy Acquisition Method And Nonlinearity

Railway is an important infrastructure in China.As the basic means of transportation for medium and long-distance passenger transportation and cargo transportation,it plays an important role in our daily life,so it is very important to ensure the safety of railway transportation.In order to achieve these goals,the Internet of Things monitoring system for railway side bridges and culverts,the track health monitoring system,etc.are essential.In areas with harsh natural environments,the wireless monitoring nodes of the track are powered by batteries,but there are some obvious risks in battery power supply.Studying environmental energy recovery technology can not only reduce the risk of battery power supply,but also realize the self-power supply of wireless monitoring nodes.Among the environmental energies,solar energy,wind energy,and heat energy are greatly affected by weather and seasons.The power generated by noise energy is too low,and the power generated by vibration energy can meet its electricity demand to a certain extent.In this paper,the principle of piezoelectricity is used to collect the vertical vibration mechanical energy of the track to realize the intermittent energy supply of the track's wireless monitoring nodes.The main research work is as follows:(1)The principle of the vibration of the track plate is simply analyzed,and the low-frequency interference error is removed by filtering after the secondary integration of the vertical acceleration data of the track measured on site.After the acceleration data is processed by numerical integration,empirical mode decomposition(EMD)and detrending,the vertical vibration output response of the track plate in the time domain is obtained,and then the discrete vibration signal is separated from the discrete vibration signal by fast Fourier transform(FFT)From the time domain to the frequency domain,the vibration curve of the track in the frequency domain is obtained,and the characteristics of the frequency range of the track plate vibration and the maximum peak frequency of the vertical vibration acceleration of the track plate are obtained.(2)A single-degree-of-freedom,three-degree-of-freedom two-degree-of-freedom laminated circular plate piezoelectric vertical vibration energy harvester was designed,a concentrated parameter model was established,and motion control equations and electromechanical coupling equations were listed.The fourth-order Runge-Kutta method was used to study the output characteristics of the single-degree-of-freedom vibration collector.Aiming at the design scheme of the two-degree-of-freedom piezoelectric vibration energy harvester,the harmonic balance method is used to obtain the amplitude-frequency response curves of the output voltage and output power under simple harmonic excitation.First-order natural frequency and second-order natural frequency.The correctness of the analysis results is verified by direct numerical simulation,and the vibration energy harvester between the secondary mass and the track plate is the best design scheme of the vibration energy harvester.The energy harvesting effect of this scheme is much higher than other Two options.The structural parameters of the collector were optimized and simulated,and it was found that the optimized energy efficiency of the vibration energy collector was higher,and the bandwidth was also increased.(3)In the optimal design scheme of the vibration energy collector between the second-level mass and the track plate,a nonlinear term is added to study its nonlinear characteristics.It can be known from the frequency response curve that the forward frequency sweep curve and the reverse frequency sweep curve of the nonlinear vibration energy harvester do not coincide.Under simple harmonic excitation,among the three nonlinear term design schemes,the optimal nonlinear design scheme was selected by comparison.After adopting the optimal nonlinear term design scheme,the rms output power and peak output power of the collector have been significantly improved.Through research,it was found that both linear and non-linear vibration collectors of two degrees of freedom can purposely enhance any of the two resonance peaks by adjusting the system stiffness coefficient,resistance and other parameters to achieve the purpose of resonance resonance with orbital vibration.