Research On Vibration Energy Harvesting Based On Piezoelectric Cantilever Structure And Its Application In Bridge Engineering

The development of energy recovery technology is an extremely urgent on account of the question of energy shortage has appeared in numerous nations around the world in recent years.Among them,the research on piezoelectric energy harvesting technology is widely noted particularly in bridge traffic territory,because a large amount of mechanical energy output to the environment is very valuable for energy recovery technology.In which case,the mechanical energy can be converted into electric energy by employ piezoelectric energy harvesting technology for using by various radio sensors in the bridge monitoring system,which is able to overcome the traditional problems in short life and the replacement of battery.Thus,the paper designs a higher efficient and more applicable device in virtue of theoretical analysis,numerical simulation,experimental analysis and other methods to explore the electromechanical characteristics of piezoelectric energy in bridge engineering.The relevant research works and conclusions are as follow:(1)On the basis of Euler Bernoulli beam theory,the distribution parameter governing equation of the cantilever bistrystal piezoelectric energy collector is established and solved by the modal superposition method to obtain the analytical solutions of characteristic frequency,voltage output and power output.Then the entity collection device and the relevant collection performance results are obtained with finite element software ANSYS.Subsequently,the relevant collection performance results obtained from the experiment are analyzed after the entity collection device is designed by building a scientific experimental platform.Finally,the results of the above three analysis methods are compared to verify the correctness and accuracy of the theoretical and simulation analysis.(2)The parametric analysis of the cantilever twin-crystal piezoelectric energy harvesting device is carried out by theoretical analysis and numerical simulation to make a thorough inquiry of the influence law of the dynamic characteristics and electromechanical characteristics of the collecting device of the structure parameters and the dynamic characteristics of piezoelectric parameters.The structure parameters include the covering position of piezoelectric material,the density of the quality of block,cantilever beam aspect ratio,the piezoelectric layer and another Piezoelectric parameter include piezoelectric constant and dielectric constant of piezoelectric materials.The result display that the consequence of the theoretical analysis method and the numerical simulation method are analogical.In additional the piezoelectric constant has the optimal solution;other parameters have a unidirectional effect on the natural frequency as well as collection performance of the device.The positive piezoelectric effect is considered in theoretical analysis based on Euler Bernoulli beam model,while the inverse piezoelectric effect occurs simultaneously with the positive piezoelectric effect is not taken into account.(3)The vibration energy collection analysis is carried out for the strap-type monorail bridge and continuous girder highway bridge respectively.Firstly,the numerical models of two bridges are established by finite element software Ansys.Then,behind the analysis of the acceleration data under coupled vibration of the vehicle-bridge,the corresponding double-crystal cantilever piezoelectric energy harvesting device is designed and verified by finite element simulation.Finally,according to speed,vehicle size,road level,traffic and other factors are divided into imparity operation mode,analyzing and comparing the voltage output and collected energy under each working condition respectively.The results showed that: the speed of the vehicle would not change the bridge vibration acceleration amplitude,but with the condition of the heavier vehicle、the worse road conditions、the higher traffic volume and other factors will significantly improve the bridge vibration acceleration amplitude and further increase the output voltage of the collector as well as the total energy collection.Moreover,the study compares the daylong energy collection for two bridges through daily traffic statistics.Though the collector power of principal period in the accumulator installed in urban monorail bridge is higher than the accumulator installed in the continuous beam bridge,the daily total collecting energy well below the collector installed in highway bridge.