Hydroelastic effects on the vertical bending moment of a container ship in head and oblique seas

Large-sized ships like Ultra large container ships (ULCS) experience severe hydroelastic vibrations like springing and whipping. This study numerically investigates the performance of a time domain method to assess the effect of structural vibration in calculating of vertical bending load of an ULCS. The proposed 2-D body nonlinear time-domain numerical method comprises a seakeeping solver based on potential flow theory and a structural solver based on Timoshenko beam theory. The simulations are carried out in the head and oblique waves for various forward speed conditions. The solver captures the effects of high-order springing and whipping in vertical bending. The numerical method identifies the whipping effect based on the slamming associated with the relative motion of the ship. The vertical bending moment is calculated in both regular and irregular waves, and the results are compared with the experimental results. The statistical evaluations of available results for irregular waves are carried out and presented. The numerical results are in good agreement with the experimental ones for most of the analyzed cases.