Structural Quality Factor of Flo-TENG under Stochastic Wave Excitation

Triboelectric nanogenerators (TENGs) have recently emerged as a promising technology for efficient water wave energy harvesting. However, there is a paucity of clear guidance regarding the optimal designs of TENGs and their shells to achieve efficient absorption and conversion of water wave energy in real random waves. Herein, from the perspective of wave-body interaction and energy transfer, this paper proposes a structural quality factor (Q_unit) for the quantitative evaluation of both the motion of floating triboelectric nanogenerator (Flo-TENG) shells and their capability to absorb and convert water wave energy efficiently. The factor is further subdivided into the amplitude structural quality factor (Q_acc), which characterizes shell motion amplitude, and the frequency structural quality factor (Q_f), which describes shell motion frequency. This paper systematically investigates the impact of various shell parameters such as bow shapes, curvatures, inclinations, and immersion ratios on Q_acc and Q_f. The findings indicate that variations in shell shape result in distinct Q_unit values along different axial directions of wave propagation. These variations directly influence energy absorption efficiency in these directions. These results provide fundamental guidance for the design of high-performance Flo-TENG shells and the selection of internal energy harvesting directions to enable more efficient energy conversion.