Evaluation of negative stiffness mechanism on a pitch-type wave energy converter

Abstract

The current study focuses on the application of the nonlinear negative stiffness mechanism to a Salter's duck, which is a well-known wave energy conversion (WEC) device known for its efficiency of 90% in 2D regular waves. Despite the proven efficiency of WEC devices, they face the challenge of producing a stable system that can effectively extract energy from constantly changing wave conditions. Recent studies have shown that the use of negative stiffness can address this issue, and this approach has been adopted in the present study for the pitch-type WEC-rotor (Salter’s duck). The study employed a time domain analysis based on linear potential theory to examine the impact of factors such as spring length and stiffness on wave energy extraction in both regular and irregular wave conditions. The results of the study showed that the incorporation of negative stiffness improves the extraction of wave energy. © 2023 by the International Society of Offshore and Polar Engineers (ISOPE).