MEMS Vibrational Power Generator for Bridge Slab and Pier Health Monitoring

Micro energy harvesters (MEH) based on microelectromechanical systems (MEMS) are rapidly developing, providing a green and virtually infinite energy source. The electrostatic vibratory power generator outputs electric power when it vibrates, motivating us to apply it to vibrating civil infrastructures excited by ambient and daily traffic loadings. In this study, an innovative monitoring system utilizing MEH devices was proposed for detecting slab damage and pier scours for bridge structures. Its performance was numerically investigated with finite element models, where the damage in slabs was modeled with a reduced Young’s modulus and scours with fixed boundaries of inclined depth. It was shown that the powers generated at each MEH varied as the target structure’s modal frequency shifted and amplitude changed by damage or scour. A power generation index was proposed to identify slab damage and a reference-free method was introduced to detect uneven pier scours. Utilizing an electrostatic vibration-based MEH (MEMS vibrational power generator), this pioneering study showed that MEMS vibrational power generators can work as sensors for an infrastructure structural health monitoring system.