Wave energy harvesting using nonlinear stiffness system

•A nonlinear stiffness mechanism installed in a floating point absorber in regular waves allowed for studying the influence of the nonlinear behavior on wave energy harvesting.•The nonlinear stiffness system could improve the efficiency of wave energy harvesting, increasing mean power, by both pushing up the natural period and broadening resonance.•The whole analysis process could be used as a reference for the preliminary design of nonlinear stiffness system to enhance the wave energy harvesting of a floating point absorber. A nonlinear stiffness mechanism installed in a floating point absorber (FPA) in regular waves allowed for studying the influence of the nonlinear behavior on wave energy harvesting. Static analysis of nonlinear stiffness system and time domain numerical simulations based on Cummins’ equation evaluated the effects of power take-off (PTO) damping, system stiffness and geometry dimensions. The results may apply to the evaluation of the balance between energy harvesting performance and practical design limitations. The nonlinear stiffness system improved the efficiency of wave energy harvesting, increasing mean power, by both pushing up the natural period, and broadening resonance, therefore proving more competitiveness.