Reliability evaluation of the roll motion under the wind and irregular beam waves

This paper intends to study the stochastic response and reliability of the roll motion under the action of wind and wave excitation. The roll motion in random beam seas is described by a four-dimensional (4D) Markov dynamic system whose probabilistic properties are governed by the Fokker–Planck (FP) equation. The 4D path integration (PI) method, an efficient numerical technique based on the Markov property of the 4D system, is applied in order to solve the high dimensional FP equation and then the stochastic statistics of the roll motion are derived. Based on the obtained response statistics, the reliability evaluation of the ship stability is performed and the effect of wind action is studied. The accuracy of the 4D PI method and the reliability evaluation is assessed by the versatile Monte Carlo simulation (MCS) method.