Response of FPSO Systems to Squalls

Abstract

Squalls are mesoscale sudden wind-speed increases that can occur worldwide and are a design driver for FPSO systems in areas the other design environmental conditions are relatively benign, e.g. offshore West Africa. Squalls are transient winds which rapidly reach a peak wind speed (up to 50 m/s) and then decay to low speeds in a span of 60 to 90 minutes. As squalls are transient phenomena traditional steady-state analysis techniques cannot be used for the global analysis or the development of the extreme response estimates. This paper focuses on the characterization of the squall environment and the impact of various parameters on the response of FPSOs. The responses of both spread and turret moored FPSOs are presented and the difference in response is discussed. The paper then focuses on a parametric study on a representative single degree of freedom model of a spread-moored FPSO with an emphasis on the estimation of the extreme response and its dependence on sample size.

Wave-induced vibration control of Floating production storage and offloading systems by tuned mass damper inerter

“…The finite element modelling of FPSOs with storge tanks in the hull requires a considerable number of degrees of freedom, making the computational analysis highly tedious. Hence, the lumped mass model is being considered in studies on the FPSO under unidirectional wave excitation (Duggal et al, 2011; Gurusamy et al, 2019; Gurusamy and Kumar, 2021). Further, a liquid-containing tank under lateral excitation is commonly modelled by mass-spring-dashpot systems representing an impulsive or “dead” mass, and a series of sloshing masses, with the fundamental sloshing mode predominating (Ibrahim et al, 2001).…”

Structural Integrity of Welded Joints: An Investigation of the FPSO Module Stools

“…[9]. ECA is a methodology that makes use of fracture mechanics theory to determine the significance of welding flaws, allowing to carry out quantitative estimations of the risk of materials' failure by fracture and fatigue, especially for existing flaws on welded structures, as is the case in many FPSO projects [10][11][12].…”