Oscillating water column wave energy converter with flexible structured sheet material for enhanced power output

Abstract

Flexible wave energy converters (FlexWECs) are increasingly recognized for their potential to improve efficiency, reliability, and survivability in extreme ocean conditions. This study explores two strategies to enhance FlexWEC performance: customizing material properties and optimizing structural configuration. A structural sheet material with a specific pattern was developed to increase device power output under lower external loading, while membrane pre-stretching was investigated to tune the system’s natural frequency and improve dynamic response. The material’s mechanical behaviour was characterized through uniaxial tests, and a hyper-elastic YEOH model was applied to describe its nonlinear response. High-fidelity fluid–structure interaction simulations were performed to compare the performance of a flexible oscillating water column wave energy converter (WEC) using the newly developed structural sheet material against conventional natural rubber, with a focus on fluid dynamics, membrane deformation, stress distribution, and power output. The results indicate that, compared to natural rubber, the structural sheet material increases membrane deformation by 143%, reduces maximum stress by 14% at resonance, and boosts power output by 245%. Additionally, pre-stretching significantly increases the WEC system’s natural frequency, promotes a more uniform stress distribution, which reduces fatigue risk, and increases power output by 54%. These findings highlight the potential of these strategies to enhance FlexWEC efficiency and reliability, offering valuable insights for adapting such systems to complex and variable marine environments.