Application of CFD–FEA coupling to predict hydroelastic responses of a single module VLFS in extreme wave conditions

Freak waves , as a kind of strong nonlinear waves , have a great threat to the safety of Very Large Floating Structures (VLFS). Freak wave produces enormous wave height, which caused the hydroelastic responses on the VLFS to increase significantly. Nevertheless, due to the complexity of the highly nonlinear interactions between waves and VLFS, studies of wave-induced loads and the hydroelastic responses of VFLS in freak waves are rare. In this paper, a fluid-structure interaction technique that strongly connects the CFD and FEA solvers is proposed to evaluate the wave-induced loads and hydroelastic responses of a single module VLFS under freak wave circumstances. The accuracy and reliability of the CFD–FEA coupling approach is validated through the comparisons of the results of hydroelastic responses of VLFS in regular waves with those from other numerical methods . Finally, the global motion and vertical bending moment (VBM) of VLFS in freak wave conditions are investigated. The result shows that the freak wave will lead to the global motion of VLFS being multiplied several times and largely increasing the instantaneous maximum VBM. The novel findings in this study will provide a reference for the structural design of VLFS under survival conditions. • A two-way CFD–FEA coupling method for predicting global motions and hydroelastic responses is proposed. • Numerical computations are performed on a single module very large floating structure (VLFS) in regular head waves. • Freak waves are simulated accurately using phase modulation method in CFD solver. • The hydroelastic responses of the VLFS in freak waves are investigated by the developed method. • The nonlinear high-order harmonics of wave frequencies of hydroelastic responses are captured well.