Nonlinear Effects in Predicting the Motion Response of Intact and Damaged Mobile Platforms

In this paper the importance of non-linear terms in wave excitation and hydrodynamic reaction forces, and of metacentric height and coupling between the different modes of rigid-body motion, in predicting the dynamic response of an intact and damaged platform in waves is highlighted. The motion response predictions obtained using non-linear large motion equations in six degrees of freedom are illustrated to indicate the behaviour of a semi-submersible platform in waves during intact, flooding and post-flooding conditions. The results of the numerical motion response predictions are compared with measurements taken during model tests carried out in the wave tank at the University of Glasgow.