Harvesting traffic-induced bridge vibrations

This paper demonstrates the harvesting of low-frequency and low-amplitude vibration energy from a suspension bridge. The performance of a Parametric Frequency Increased Generator (PFIG) is evaluated at different locations along the bridge. Bridge vibrations have very low acceleration 0.1-1 m/s² and variable frequency characteristics (1-40 Hz), making them very challenging to harvest. Field test results show consistent operation along the length of the bridge, producing 0.46-0.72 μW of continuous (average) power (peaks in the range of 30-100 μW), independent of the location of the harvester on the bridge, and without any modifications or tuning. These results pave the way for installing a network of wireless structural health monitoring sensors throughout the bridge without regard to the specific characteristics of the vibration at each location. The fabricated device has a volume of 43 cm³ (68 cm³ including casing).