Authors:
Anis A. Mohamad Ali; Ahmed Al-Kadhimi; Majed Shaker;
Abstract:
Unlike structures in the air, the vibration analysis of a submerged or floating structure such as offshore structures is possible only
when the fluid-structures is understood, as the whole or part of the structure is in contact with water. Using the commercial F.E.A.
program ANSYS (v.12.0) (to model the Winkler and Brick-full bond models) and program ABAQUS(v.6.9) (to model the Brickinterface
model), the stress matrix considering a dynamic load was superposed on the stiffness matrix of the structure. A time domain
solution is recommended, using the generalized Morison’s equation by FORTRAN90 program to construct a program to calculate the
wave forces, and Airy's linear and Second Order Stoke's wave theories are employed to describe the flow characteristics by using
MAPLE13 program (to solve and apply the boundary conditions of the problems on Laplace's equation), and the results are compared and discussed. Both free and forced vibration analyses are carried out for two case studies.
Keywords:
Natural frequency, Fixed jacket offshore, Finite element method, Validity of wave theory, Dynamic analysis