Dual inclined perforated anti-motion plates for mitigating hydroelastic response of a VLFS under wave action

Abstract

This paper investigates the hydroelastic responses of a mat-like, rectangular very large floating structure (VLFS) edged with dual horizontal/inclined perforated plates using analytic method, numerical method and experimental test. In the analytic method, the eigenfunction expansion-matching method (EEMM) for multiple domains is applied to evaluate the diffraction and radiation potentials, and then the elastic equation of motion is solved by the Rayleigh–Ritz method. In the numerical model, the modal eigenvector equation of the VLFS with some discrete Mindlin plate elements are obtained by using the finite element method (FEM), whereas the boundary element method (BEM) is applied to solve the water wave equation. The hybrid finite element method-boundary element method (FEM-BEM) solutions are further employed for more general cases including inclined perforated anti-motion plates. Both analytic and numerical solutions are also validated against a series of experimental tests. The effectiveness of dual perforated plates in reducing the deflections of VLFS, is systematically assessed for various wave and plate parameters, and the performance of the anti-motion device can be significantly improved by selecting the proper design parameters. Based on the selected optimal parameters, the response reduction of VLFS with different locations of lower perforated plate is further highlighted.