Estudo das características estocásticas do roll paramétrico

Abstract

In the present work, three mathematical models for simulation of motions of floating systems have been developed. The developed models are capable of simulating the heave, roll and pitch motions under regular and irregular longitudinal waves. Especial effort has been made in capturing in an accurate and efficient manner the restoring actions in the developed models. This is a fundamental feature required in order to reproduce numerically the parametric roll resonance phenomenon. Numerical realizations of the motions of a containership type vessel have been generated for the purpose of studying the stationarity and ergodicity of the roll motion under parametric resonance conditions. The results obtained have shown that for containerships the stochastic roll process could be consider as a stationary process. Finally, the extreme roll responses have been used for fitting the Generalized Extreme Value Distribution (GEVD) and the Generalized Pareto Distribution (GPD). Then, using the fitted GEVD, the return period and the time between events for roll motions have been computed for two wave conditions.