Performance investigation of an oscillating-body WEC with the tristable energy capture mechanism

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This paper conducts an investigation into the energy harvesting performance of a tristable wave energy converter (WEC) utilizing a dual snap-through mechanism. Existing studies have indicated that the bistable characteristics inherent in such mechanisms can substantially improve the power output of oscillating-body WECs. The dual snap-through mechanism comprises four symmetrically configured inclined springs, with its energy harvesting behavior being highly dependent on the geometric arrangement and stiffness of the springs. A distinctive feature of the tristable system is the emergence of three potential wells. Following the development of a mathematical model for the nonlinear WEC, this study first examines the mechanism through which multiple potential wells contribute to enhanced energy conversion. Subsequently, a comprehensive parameter analysis is conducted to evaluate the influence of variations in the parameters of the dual snap-through mechanism and wave amplitudes on the energy conversion. The results demonstrate that appropriate stiffness and projected lengths of the springs can markedly improve the power output of the WEC. Furthermore, by adjusting the parameters of tristable mechanism, the WEC can achieve superior energy generation even at high wave frequencies or under low-amplitude excitation. Finally, the current study can offer some valuable insights for the design of other multistable WECs. • A dual snap-through mechanism is adopted to realize the tristable energy capture feature of a heaving WEC; • The motion characteristics of the WEC are utilized to analyze how the tristable mechanism enhances its performance; • Appropriate physical parameters of the tristable mechanism can markedly enhance the energy capture of the WEC; • By adjusting the initial condition of the tristable mechanism, the WEC can achieve superior energy generation even under low-amplitude excitation.