Constraint effects on the hydroelasticity of very large floating structures

Abstract

Offshore structures are continuously subjected to wave-induced loads, resulting in both rigid-body motion and elastic deformation. In very large floating structures (VLFSs), hydroelastic deformation is primarily characterized by vertical displacement, encompassing both oscillatory motion and flexible deflection. Hydroelastic analysis typically involves imposing constraints to restrict body motion in waves, which can significantly influence deformation behavior. To assess the impact of these constraints, this study examines how different boundary conditions affect the hydroelastic response of VLFSs. Specifically, five test cases with distinct constraint conditions are designed to systematically evaluate their effects across multiple wavelengths. A coupled numerical methodology integrating computational fluid dynamics (CFD) and computational structural dynamics (CSD) is developed to analyze hydroelastic deformation under these conditions. Strain distributions at key locations along the floating structure are examined under varying wave conditions. Results indicate that spring constraints provide a stable deformation pattern, aligning well with physical expectations in both long and short waves. This study highlights the critical role of constraint selection in VLFS modeling and suggests that future research should explore multi-directional wave effects and diverse restraint configurations to enhance VLFS design and performance.