With the trend of increasing dimensions of large ships, especially for the ultra large container ship, the hydroelasticity of ship in waves become more and more important. The hydroelastic responses, such as springing and whipping, happen more frequently even in sea states that were not regarded as severe before. It is of great importance to estimate the wave and vibration induced loads of ships accurately. In the present work, a fluid-structure interaction (FSI) method is developed based on CFD-FEM method to predict the hydroelastic response of a 20000TEU container ship in waves. Fluid field is solved by RANS method with OpenFOAM. Structural vibration is represented by Timoshenko beam model and solved by Newmark-beta method. The springing response of container ships in different regular waves are calculated. The predicted results, including ship motions, vertical bending moment, are compared with the experimental results. and the present CFD-FEM solver is proved to be reliable in predicting hydroelastic response for ultra large container ship in waves.
With the trend of increasing dimensions of large ships, particularly ultra large container ships with their length reaching approximately 400m, the ships become more flexible. The hydroelastic responses, such as springing and whipping, happen more frequently even in sea states that were not regarded as severe before. In recent years, a few critical ship accidents due to fatigue cracks and structure failure caused by hydroelastic responses took place unexpectedly. Two severe accidents involving large container ships occurred: MSC NAPOLI in 2007 and MOL COMFORT in 2013 (Hirdaris et al., 2023), as shown in Fig. 1. Both vessels were reported to have failed in a hogging condition due to the collapse of the hull girder. These accidents have drawn attention from the governmental organization (IMO), classification association (IACS) and international technical committees, such as ITTC and ISSC. Now, a joint work group between ISSC and ITTC is also carrying out research on this important issue of springing and whipping responses of ultra large container ship.
