A Numerical and Structural Response of FPSO Under Wave Induced Motions
Greeshma George1, Sheeja Janardhanan2

1Greeshma George, Department of Civil Engineering, SCMS School of Engineering and Technology, Karukutty, Ernakulam (Kerala), India.
2Sheeja Janardhanan, Department of Mechanical Engineering, SCMS School of Engineering and Technology, Karukutty, Ernakulam (Kerala), India.
Manuscript received on 21 May 2019 | Revised Manuscript received on 07 June 2019 | Manuscript Published on 15 June 2019 | PP: 267-271 | Volume-8 Issue-1S2 May 2019 | Retrieval Number: A00610581S219/2019©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: FPSO (Floating Production, Storage and Offloading) is generally a ship used by oil and gas industry for performing a multitude of tasks and is moored to the ocean bed for the extraction of oils and hydrocarbons. Due to continuously varying cyclic load, FPSO undergoes progressive and localized structural deformations leading to fatigue damage. Structural analysis of the FPSO is important to establish the strength and stability of the structure. A moored FPSO generally has three degrees of freedom viz. heave, roll and pitch, under following sea conditions. In this paper, a numerical study on the FPSO has been conducted with the help of CFD (Computational Fluid Dynamics) analysis under calm sea-stateand the subsequent structural response of the system has been calculated by finite element method. CFD studies have high potential in determining the effect of any complex fluid loading with reasonable degree of accuracy. Geometric modeling and meshing have been carried out in ANSYS ICEM CFD. An unstructured grid system has been used here and the prescribed motions on the hull in heave, roll and pitch have been brought in using user defined function (UDF) module of the commercial CFD solver, FLUENT. Air water interface has been captured using volume of fluid method. The lift and drag forces are calculated from the simulations. Fluid forces have been validated against their analytical counterpart using Linear wave theory and Strip theory. Structural response of 3D hull has been predicted in ANYS Workbench with the forces determined from the CFD solver as input. Equivalent stress distribution and total deformations of the structure have been studied using static analysis. Understanding the behavior of structure under various motions provides an insight and guidance to the design calculations of the FPSO in order to withstand fatigue loading.
Keywords: FPSO, CFD, Pitch, Heave, Roll, Lift, Drag, Structural Response.
Scope of the Article: Structural Engineering