doi:10.3850/978-981-08-7619-7_P009

ABSTRACT

This paper reviews the formulation of problems related to extreme ship motions in random waves and approaches to solving these problems. The dynamical system is characterized by integro-differential equations. The bandwidth of excitation is medium; stiffness is extremely nonlinear and random. In standard ship design, the main tools for the engineering evaluation are model experiments and numerical simulations using potential flow hydrodynamics with empirical models for non-potential flow forces. However, a direct Monte Carlo approach is impractical because of the high cost of running these tools and the rarity of extreme motion events. To obtain a practical solution, the principle of separation is used to separately consider the nonlinear phenomena resulting in an extreme response and the conditions that lead to the occurrence of such phenomena. This paper discusses fundamental aspects of three methods that use the principle of separation: the peaks-over-threshold/envelope peaks-over-threshold method, the split-time method, and the wave group method.

Keywords: Rare events, Monte Carlo method, Stability of ship in waves.

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