Collision analysis of a cylindrical offshore structure with fluid region due to impact

Abstract

The main object of this research is to establish the impact simulation techniques for offshore structures. The collision between ship and offshore structure is generally a complex problem and it is often impractical to perform rigorous finite element analyses to include all effects and sequences during the collision. This paper is focused on the structural behaviors of fixed cylindrical type offshore substructure with fluid part. A significant part of the collision energy is dissipated in terms of strain energy and the contribution from the elastic strain can normally be neglected. On applying the impact force of a service boat to the cylindrical structure, the maximum acceleration, internal energy, and plastic strain are calculated for each load cases using LS-Dyna finite element software. The fluid-structure interaction analysis was performed using ALE (Accidental Limit State) method which is possible to apply fluid region on the impact problem. A parametric study is carried out by changing design variables of the velocity of service boat and the thickness of the cylindrical structure considering fluid part. It is concluded that this paper provides designing process used for the rubber fender considering service boat impact. Copyright ？ 2015 by the International Society of Offshore and Polar Engineers (ISOPE).