FPSO HULL STRUCTURES WITH SANDWICH PLATES IN CARGO TANKS

João Pedro Cunha Machado da Silva

Key information

Authors:

João Pedro Cunha Machado da Silva (João Pedro Cunha Machado da Silva)

Supervisors:

Paulo Maurício Videiro (Paulo Maurício Videiro); Baiqiao Chen (Baiqiao Chen)

Published in

12/15/2021

Abstract

Nowadays, the floating production storage and offload system (FPSO) is one of the most common platform types for offshore oil production. The traditional FPSO hulls are built with steel stiffened panels, similar to tankers structures and the classification societies demand its inspection. However, these surveys are a time consuming and risky activity. The traditional arrangement of the stiffened panels creates obstacles for automated cleaning and inspections by remote devices. In order to overcome this problem, a proposed approach is the use of the sandwich plates system (SPS) in cargo tank structures. This paper summarizes the results of an initial study for the design and construction of FPSO’s hulls with SPS. The main goal is to have the walls and bottom of the cargo tanks free of stiffeners to allow remote cleaning and thickness inspection of bottom and longitudinal bulkhead plates using autonomous equipment. This research is carried out by first designing the hull with a conventional structural arrangement using steel according to the ABS rules as a benchmark. Following that, the equivalent hull structure with sandwich plates is designed in accordance with the guidelines for SPS construction from DNV rules. Finally, this paper provides the results of a finite element analysis to compare the stresses and ultimate strength of both types of structures. Briefly, the main results were that the SPS design provided a reduction of 2.8% of the total weight and a better overall structural performance by an increase of 26% for the ultimate strength of the hull.