Electromechanical coupling and energy harvesting of circular rings

Ring shell structures often exhibit oscillatory behaviors during their operations. It is a crucial challenge to extract vibration energy, which is always wasted, to convert to useful electric energy. In this study, the concept of energy harvesting based on a circular ring laminated with a piezoelectric patch is established to achieve this purpose. The electrical device is assumed to be an equivalent resistance in the close-loop circuit as a simplified energy harvesting system. Due to the direct piezoelectric effect, the electromechanical coupling mechanism of the energy harvesting system is analyzed. Then, the electric power on the resistance is obtained. Case studies with respect to different system parameters, such as the equivalent resistance, excitation frequency, and the ring size, are conducted to optimize the modal power. Results show that the maximal modal power output is related to the equivalent resistance, the excitation frequency, as well as the ring radius. The optimal modal parameters are evaluated to maximize the energy harvesting effectiveness and provide a design guideline of ring-type energy harvesters for practical applications.