Power wireless sensors via regenerative electromagnetic TMD

Lack of sustainable power source prevents wireless smart sensors (WSS) from widespread application in long-term structural health monitoring (SHM). Some efforts have been reported in literatures to solve this problem by using solar energy, micro-wind turbine technology and vibration-based energy harvester. In particular, a variety of mechanisms or materials have been explored for vibration-based energy harvesting techniques, including electromagnetic induction, piezoelectricity, electrostatic generation, dielectric elastomers and so on. However, there still exists a gap between the power output of most existing vibration-based energy harvesting devices and the power demand of commercially available WSS. This paper presents an experimental study on a novel energy harvesting solution to WSS-utilizing regenerative electromagnetic tuned mass dampers (EMTMD). The EMTMD, as a key element in the system, is composed of a pendulum-type TMD and a rotary electromagnetic damper. When connected to an energy harvesting circuit (EHC), it converts vibration energy of structures to electrical energy, and functions in both structural vibration reduction and sensor power supply. The functionality of the regenerative EMTMD system was validated in this study through shaking table tests of a single-story steel frame model equipped with an integrated EMTMD, EHC and WSS system. The experimental results revealed that the proposed regenerative EMTMD system can provide regenerative and economical power to WSS. The harvested power under random ground motions (RMS acceleration = 0.05g) reaches up to 312.4 mW. The proof-of-concept experiments clearly demonstrate the novel EMTMD is a promising device to be exploited as a sustainable and regenerative power source to WSS.