ESTUDO DA CONTRIBUIÇÃO INERCIAL E DE AMORTECIMENTO DE LINHAS DE ANCORAGEM NO MOVIMENTO DE MONOBOIAS

Abstract

In offshore oil production activities, monobuoys comprise oceanic terminals used by offloading ships to control the oil transference to the coast. They are relatively small structures, with accentuated dynamic responses when submitted to wave forces. Due to their lower inertia when compared with other types of floating systems, their mooring lines and risers lines may contribute directly with its static and dynamic behavior, evidencing a structural and hydrodynamic coupling between monobuoy and lines. In the search of an analysis methodology that may take advantage on both coupled and uncoupled formulations, this work presents procedures to evaluate, based on coupled simulations, the inertial and damping contribution of the mooring lines and risers into the monobuoy’s responses. These values may be inserted as input parameters into a calibrated uncoupled simulation to obtain dynamic responses with higher accuracy and lower computational cost. This work will present a case study of a standard monobuoy, with 9 mooring lines, located into a 90 meter water depth, comparing the motions provided by coupled and uncoupled simulations, with and without the proposed calibration procedure, and assessing the computational costs.