Modelling and analysis of ship roll oscillations interacting with stationary icebergs

• Published in: Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science
• Main Authors: Grace, I F, Ibrahim, R A
• Format: Article in Journal/Newspaper
• Language: English
• Published: SAGE Publications 2008
• Subjects: Mechanical Engineering; Arctic; Iceberg*
• Online Access: http://dx.doi.org/10.1243/09544062jmes935; http://journals.sagepub.com/doi/pdf/10.1243/09544062JMES935

Impact dynamic interaction of ships with solid ice or stationary rigid structures is a serious problem that affects the safe operation and navigation in arctic regions. The purpose of this study is to present two analytical models of impact interaction between ship roll dynamics and one-side rigid barrier. These models are the phenomenological modelling represented by a power law in stiffness and damping forces, and Zhuravlev non-smooth coordinate transformation. Extensive numerical simulations are carried out for all initial conditions covered by the ship grazing orbit for different values of excitation amplitude and frequencies of external wave roll moment. The basins of attraction of safe operation are obtained and reveal the coexistence of different response regimes such as non-impact periodic oscillations, modulation impact motion, period-added impact oscillations, chaotic impact motion, and unbounded rotational motion. The results are summarized in the bifurcation diagram in terms of response-excitation amplitudes plane. The stability fraction index is obtained for different values of excitation frequency based on the ratio of the area of bounded roll oscillations to the total area of the grazing orbit.