A real-time sensing system based on triboelectric nanogenerator for dynamic response of bridges

The strain of bridges under traffic loads is time-varying and of small amplitude(～10-6), which is a type of cumulative response and needs long-term continuous monitoring. To precisely capture the time-varying responses, a dynamic strain triboelectric nanogenerator（TENG） sensor with superior response capability, sensitivity, self-powered, and long-term stability is proposed in this paper. An analytical correlation between the structural strain response signal and the detected electrical signal is established for long-term continuous quantitative strain measurements based on the principles of contact electrification and electrostatic induction. A series of experiments are conducted to investigate the output performance of the proposed lateral-sliding mode TENG sensors. The results reveal that, with the loading condition with frequencies lower than 10 Hz, the time-varying strain responses of the steel bridge within the range of 3 to 150 microstrains can also be detected with high precision of 0.1 microstrains. And it achieves long-term stability after 10000 loading cycles compared with commercial sensors. The proposed novel sensing theory and method based on TENG technology can be applied as a new alternative approach for monitoring realtime structural strain information quantitatively with general applicability and feasibility for bridges.