AN EXPERIMENTAL STUDY OF NONLINEAR BEHAVIOUR IN ROLL AND CAPSIZE

Article type: Research Article

Authors: Cotton, B. | Spyrou, K.J.

Affiliations: Centre for Nonlinear Dynamics and its Applications, University College London, United Kingdom | Department of Naval Architecture and Marine Engineering, National Technical University of Athens, Athens, Greece

Abstract: In this paper we present the results of a series of capsize tests based on a prismatic model ship. The aim of the experiments was to study the significance of some nonlinear phenomena predicted in theoretical studies of roll motion. Regions of bistability are observed near linear resonance. It is verified that, near resonance, the freqency-response curve is skewed towards lower frequencies due to the softening nature of the GZ curve. The experimentally derived capsize boundary is then compared with the theoretical one. Finally we present some evidence for the sensitivity of capsize to initial conditions and discuss the importance of applying this to a testing procedure.

Journal: International Shipbuilding Progress, vol. 48, no. 1, pp. 5-18, 2001