高速铁路桥梁随机振动能量收集效率的评估方法与优化理论

Improving the efficiency of stochastic vibration-based energy harvesting could not only resolve the long-term energy providing problem for wireless sensor nodes of the bridge SHM system, but also provide energy for lighting and other facilities on the bridge. The key of achieving this is to determine reasonably the natural frequencies of the energy harvesters on the bridge. However, current research for energy harvesting of high-speed bridges is limited to deterministic analyses, thus could not obtain the best natural frequencies of the harvesters. The program is intent to establish the approach of estimating the efficiency of the energy harvesting and optimizing the natural frequencies of harvesters, considering the time-varying and stochastic properties of high-speed bridge vibrations. Main research contents include: 1) obtaining stochastic vibrations of high-speed bridges subjected to trains by the number theory and the probability density evolution method and establishing energy harvesting model suitable for high-speed bridges; 2) establishing the model of estimating the efficiency of the energy harvesting considering stochastic input and output; 3) optimizing the natural frequencies of energy harvesters taking the efficiency of the energy harvesting as the objective function from the point of view of probability. The program could provide technique for long-term SHM of high-speed bridges, and lay the science foundation for the technique of energy harvesting of high-speed bridges, which contain both significant science sense and engineering value.

高效收集高速铁路桥梁随机振动能量除了能有效解决无线传感器网在桥梁健康监测中的长期能源供给难题，还可为桥上照明等附属设施供能，而合理地确定能量收集器的固有频率是提高能量收集效率的关键，但已有研究局限于确定性分析，难以获得能量收集器的最佳固有频率。为提高收集效率，本项目拟考虑高速铁路桥梁振动的时变性和随机性，建立高速铁路桥梁随机振动能量收集效率的评估方法和能量收集器固有频率的概率优化理论。主要内容包括：1）以轨道随机不平顺作为激励，采用数论法和概率密度演化理论获得高速铁路桥梁随机响应，建立适合高速铁路桥梁随机振动的能量收集器模型；2）考虑随机激励和随机输出功率，建立高速铁路桥梁随机振动能量收集效率的评估模型；3）以能量收集效率为目标函数，对能量收集器的固有频率等参数进行概率优化。本项目研究将为桥梁长期健康监测等提供技术手段，为桥梁随机振动能量高效采集提供科学基础，具有重要的学术意义与工程价值。

高效收集高速铁路桥梁随机振动能量除了能有效解决无线传感器网在桥梁健康监测中的长期能源供给难题，还可为桥上照明等附属设施供能。其中，最关键的问题就是如何提高能量收集效率。但实际环境激励普遍存在多方向、宽频带、多成分及低频非线性等特点, 制约了振动能量收集效果的进一步提升。本项目拟考虑高速铁路桥梁振动的时变性和随机性，提出在传统压电能量收集系统中引入惯性放大思想和非线性振子，从降低能量收集系统共振频率和拓宽系统有效输出电压频带两个方面提高能量收集效率，开展了理论、数值模拟验证等方面的研究，实现在低频随机的桥梁振动下能量收集效率的提高。本项目研究将为桥梁长期健康监测等提供技术手段，为桥梁随机振动能量高效采集提供科学基础，具有重要的学术意义与工程价值。