Numerical predictions of motions and coupled bending and torsional vibrations of containerships in regular head and oblique waves

In this paper, global hydroelastic responses of two ultra large containerships in head and oblique waves are numerically predicted by means of a combined method which is mainly focused on the high-frequency vibrations under harsh sea conditions. The Damping Zone Method is used for the achievement of infinity radiation condition and the steady and unsteady flow are solved by Taylor Expansion Boundary Element Method (TEBEM). In the structure-property research portion, an improved beam structural model is applied for the analysis of vertical modal and coupled horizontal and torsional modal. In the hydrodynamic calculation phase, the nonlinearities of hydrostatic restoring forces and 1st order incident wave forces caused by the associated ship motions as well as the slamming loads in large amplitude regular oblique seas are taken into consideration. The simulating calculations of nonlinear hydroelastic responses of two containerships are carried out. Meanwhile, the forward speed effects are analyzed. An acceptable agreement is obtained between the numerical predictions and measured data in terms of motions and loads which validates the accuracy of the proposed method in this paper.