Piezoelectric Energy Harvesting From Torsional Vibration

Torsional vibration is present in various applications, such as in oil drilling pipes, engine crankshafts, and wind turbine gearboxes. In the case of oil drilling, ever deeper wells are being drilled and sensors used to gather data from the bottom of the well. Providing an energy source for these sensors is a big challenge. Harvesting energy from torsional vibrations presents a promising solution for powering the sensors on rotational systems. We investigated the concept of torsional vibration energy harvesting using a piezoelectric transducer attached to a shaft at an arbitrary angle with respect to the axis of the shaft. A comprehensive theoretical model considering all the working modes, including d₁₅, d₃₁, and d₃₃ mode, has been developed to express the voltage outputs as functions of the mounting angle. The frequency responses of the voltage outputs over the input torque have also been studied and compared. A finite element model was also implemented to verify the theoretical results and illustrate the voltage distribution within the piezoelectric material under an external torque input.