Nonlinear bending moments of an ultra large container ship in extreme waves based on a segmented model test

Abstract

The paper presents an experimental investigation on the nonlinear bending moments of an ultra large container ship over 300 m long in rough waves. The design and calibration procedure of the scaled segmented ship model with variable cross-section backbone beam is introduced. Transfer functions of vertical bending moments at different Froude numbers, wave headings and wave heights are analyzed. Ship responses in harsh waves are analyzed and the largest wave height to wavelength ratio exceeds 1/10. It is interesting and significant to analyze the strongly nonlinear behaviors of the ship in such high waves. The resonance frequencies, proportion of high-order harmonic components, asymmetry of hogging and sagging moments as well as the phase differences between wave-frequency and high-order harmonics in extreme waves are investigated systematically.