Research on Whipping and Springing Responses of Hull based on Different Experimental Method and Nonlinear Hydroelastic Time-domain Theory

The growth in size of hull may result in serious whipping and springing phenomenon that can increase both the ultimate load and fatigue damage on the hull structure. In order to study the vibration responses of hull better, the self-propulsion and towing segmented ship model experiments of a 10000-TEU containership were carried out in a towing tank. The effect of self-propulsion and towing test methods on whipping and springing responses in different sea states is analyzed. In order to consider the effect of various vibration frequency components on load responses, a nonlinear hydroelastic method considering the wave memory function is proposed. A method is proposed for time-domain retardation function to solve limitation in the calculation of damping coefficient at high frequency. Finally, the measured results on the central hull are compared with those calculated by the linear hydroelastic theory and nonlinear hydroelastic theory, and it indicates that the nonlinear hydroelastic method proposed in this paper can predict the vibration responses better.