Hydroelastic analysis in frequency domain for annular membrane-dual floaters coupled FPV structure

Abstract：Objectives A frequency-domain hydroelastic model is developed for an annular membrane–dual floaters coupled floating photovoltaic (FPV) structure under regular waves in a FPV–aquaculture hybrid system, aiming to evaluate the effects of key structural parameters. Methods Based on linear potential flow theory and the modal superposition method, analytical expressions for the membrane modes are derived. Modal hydrodynamic coefficients are obtained using WAMIT. By enforcing displacement compatibility between the membrane and the inner and outer floaters, a coupled dynamic equation is established via the Lagrange multiplier method to solve the frequency-domain hydroelastic response. Results The maximum motion response reaches about 5 times the incident wave amplitude and occurs at the wave-facing point of the outer floater under a wave frequency of . The influence of the aperture ratio shows strong frequency dependence, mainly governing the overall response distribution and the load level on the inner floater. Under high-frequency waves, increasing the aperture expands the low-response region, while increasing floater stiffness effectively suppresses local responses. Conclusions The proposed frequency-domain hydroelastic model provides a theoretical basis for the design and optimization of annular membrane-based FPV structures.