Theoretical and numerical studies on improving absorption power of multi-body wave energy convert device with nonlinear bistable structure

For the energy supplement of deep-sea equipment, we examine a multi-body absolute motion counter-rotating wave energy converter (CR-WEC) in the research. In order to improve the capture efficiency of the absorber, a nonlinear bistable structure is proposed to improve the overall wave-following vibration capability of the CR-WEC. And then, we suggest to employing the harmonic balance method to solve the system dynamics equation in the CR-WEC 2-DOF absolute motion state. Combining the essential assumptions results in an analytical solution that is approximative. The paper also investigates the influence of system-related parameter modifications on absorption efficiency. A multi-degree-of-freedom arrangement with an unaltered overall mass is proposed to further increase the device ability to absorb energy. According to the numerical calculation and simulation results, the combination of 3-DOF state and bistable structure can make the device have the maximum capture width and peak value. In the irregular incident wave under the natural state, the multi-body bistable-linear configuration proposed in this study obtains the highest average absorption power.