NONLINEAR SHIP MOTION AND GLOBAL BENDING MOMENT PREDICTIONS IN REGULAR HEAD SEAS

In this paper, the prediction of nonlinear heave and pitch motions and global bending moments of a ship hull in regular head seas are described. The small amplitude linear theory as well as a large amplitude nonlinear prediction method are used to predict the ship motions in the frequency and time domains. The global bending moment values are predicted utilising two different methods. The first method is based on the elastic vibratory response due to the total hydrodynamic force and the second method is based on the rigid body response due to linear force superimposed on the elastic response due to impact forces. A series of measurements of ship motions and global bending moments was carried out with a container ship model at different wave frequencies, wave amplitudes and forward speeds. Theoretical prediction results are compared with the experimental data and there is a good agreement between them.