New Method Calculating the Vibration of Offshore Structure Subjected to Wave Action

Abstract

Usually, modal analysis is used for the vibration of simple offshore structures. For large structures the finite element method is applied to analyse dynamic deflections and stresses. Both methods are approximately; it is difficult to model the nonlinear component of the wave force due to the drag on each element and a common hydrodynamic damping is usually applied.

In this paper the vibration of offshore structures subject to harmonic and random waves is considered by using the dynamic stiffness matrix method (DSM method); the element drag force is obtained by considering the relative motion between the structure and sea water in detail.