Design and performance enhancement of a force-amplified piezoelectric stack energy harvester under pressure fluctuations in hydraulic pipeline systems

Pipelines are a safe and environmentally friendly way to convey fluids over a long distance. Pressure fluctuations generated by unsteady flows are a common phenomenon in hydraulic pipeline systems. In this paper, a piezoelectric stack energy harvester is designed to scavenge the vibration energy of pressure fluctuations in pipeline systems, where a force amplifier is introduced as an auxiliary booster to enhance the energy conversion efficiency under low-frequency excitation levels. The device can be integrated with health monitoring sensors to eliminate the needs of batteries or wired power supplies to individual sensors. The working principle of the force amplifier is analyzed by investigating the magnification coefficient based on a dynamic model. The optimized structural parameters are also investigated by theoretical studies. Besides, the finite element model of the force amplifier is also constructed to analyze the magnification coefficient and to validate the theoretical results. Experimental studies are also carried out to identify the effect of the force amplifier on the proposed energy harvester. The results show that there is great potential to realize a self-powered wireless sensor network technology for pipeline monitoring.