基于非线性能量阱的桥梁振动能量采集装置的适用性研究

Applicability of bridge vibration energy harvester based on nonlinear energy sink

非线性能量阱(nonlinear energy sink,NES)作为一种经典的振动控制技术,近几年在一些研究中被创新性地与振动能量采集技术相结合,取得了一系列的进展。对于桥梁结构健康监测系统而言,传感器的供能问题一直有待改善,探究基于NES的振动能量采集装置在桥梁结构上的适用性,对于桥梁结构振动能量采集的相关应用具有重要的理论意义和实用价值;以铁路简支梁桥为例,进行了针对基于NES的桥梁振动能量采集装置的适用性的讨论:(1)测试与表征了NES装置的力学特性和系统参数;(2)运用车辆-轨道-桥梁垂向耦合动力学理论和有限元法,评估不同初始激励条件下NES装置的动态响应及其能量采集效果。结果表明,安装于桥梁结构上的NES装置具有弱线性刚度和强非线性刚度特性,对初始能量大小较敏感,只有当初始位移达到一定阈值时,NES-桥梁系统中的靶向能量传递(targeted energy transfer,TET)才会被激发。初始能量低于阈值时,TET无法被激发,NES装置能量采集效率不佳。基于数值分析的结果可知,该NES装置能够在合适的桥梁振动激励下发挥出非线性特性的优势,从而获得良好的能量采集效率。

As a classical vibration control technology,nonlinear energy sink(NES)has been innovatively combined with vibration energy acquisition technology in some studies for several years,and made a series of progress.For bridge structure health monitoring systems,the problem of sensor energy supply needs to be improved.Exploring the applicability of vibration energy harvester based on nonlinear energy sink on bridge structures has important theoretical significance and practical value for related applications of bridge structure vibration energy harvesting.Here,taking a railway simply supported beam bridge as an example,the applicability of bridge vibration energy harvester based on NES was discussed.Firstly,mechanical properties and system parameters of NES were tested and characterized.Then,using the vehicle-track-bridge vertical coupled dynamics theory and finite element method,NES’s dynamic response and its energy collection effect under different initial excitation conditions were evaluated.The results showed that the NES device installed on bridge structure has characteristics of weak linear stiffness and strong nonlinear stiffness,it is sensitive to initial energy;only when initial displacement reaches a certain threshold,targeted energy transfer(TET)in NES-bridge system can be excited;when initial energy is lower than the threshold,TET can’t be excited,and the energy collection efficiency of NES device is poor;numerical analysis results reveals the NES device can exert advantages of nonlinear characteristics under appropriate bridge vibration excitation to obtain good energy collection efficiency.