Jordan Journal of Civil Engineering

Dynamic Behavior of Jacket Type Offshore Structure


Anis A. Mohamad Ali; Ahmed Al-Kadhimi; Majed Shaker;


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.


Natural frequency, Fixed jacket offshore, Finite element method, Validity of wave theory, Dynamic analysis