The use of flexible breakwaters to protect offshore areas from wave impacts has increased in recent years, owing to their cost effectiveness, environmental friendliness, and simple installation. This study proposes a finite-volume-method-finite-element-method coupled model based on waves2Foam, preCICE, and CalculiX to investigate wave attenuation by a vertical plate-type flexible breakwater under the impact of a solitary wave. The numerical model was validated by comparing the current results with previous numerical and experimental results. The proposed coupled model appropriately predicted the intricate flow phenomena of solitary waves impacting the flexible breakwater. The study systematically discusses the wave attenuation performance and structural response of the flexible breakwater under the impact of a solitary wave by considering several prominent factors: the mass coefficient, stiffness coefficient, and Poisson's ratio. Implementing a flexible breakwater effectively reduced wave energy intensity through various mechanisms, such as wave overtopping, wave breaking, and the dynamic response of the flexible breakwater. The material density had a negligible impact on the efficiency of the flexible breakwater in terms of wave dissipation and structural response; by contrast, the flexibility and compressibility of the breakwater significantly influenced the efficiency of the flexible breakwater. Employing a flexible breakwater fabricated using a compressible material is recommended for protecting coastal regions from wave-induced damage.
