NON-LINEAR FINITE ELEMENT ANALYSIS OF DECK, BOTTOM AND INNER BOTTOM PANELS IN FPSO VESSEL

Year 2020, Issue: 18, - , 09.06.2020

Özgür Özgüç

Abstract

Floating production, storage and offloading systems (FPSOs) are widely used to develop offshore oil and
gas fields. FPSOs structures shall be evaluated in order to satisfy the specifications of both in-service and
pre-service loading conditions. The key aspects of the structural assessment of FPSOs are the buckling
and ultimate strength behaviour of plate panels, stiffened panels and hull girders. The focus of this paper
is to address the buckling and ultimate strength criteria for FPSO hull structures. Buckling strength
assessment of three panels in FPSO vessel is being carried out using the non-linear finite element code
ADVANCE/ABAQUS, where the analyses involve both material inelastic effects and non-linear
geometric effects. The capacities of the bottom panels are estimated under simultaneously acting lateral
pressure and axial compression. The upper deck is only subjected to axial compression. The three panels
are located in the upper deck, the inner bottom and the bottom shell. The capacities of the bottom panels
are predicted under simultaneously acting lateral pressure (0.249 MPa for inner bottom and 0.146 MPa
for the bottom) and axial compression. For both the bottom and the inner bottom panel the pressure acts
from the ballast tank and outward. The upper deck is only subjected to axial compression. The Ultimate
Limit State (ULS) capacities have been estimated to 260 MPa for the upper deck, 205 MPa for the inner
bottom and 250 MPa for the bottom shell.

Keywords

non-linear finite element, FPSO vessel, axial compression, lateral pressure, buckling capacity

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