The Influence of Ship Collision Parameters on the Global Nonlinear Dynamic Response of a North-Sea Jack-Up Platform

Abstract

In the present study, the influence of ship collision parameters related to vessel impact energy and also the impact scenario on the global nonlinear dynamic behavior of a three-leg jack-up platform is investigated. A North-Sea three-leg jack-up platform is studied as a case which is located in water depth of about 105 m. Nonlinear elastoplastic and hyperelastic type spring models are used for ship bow and broad-side impacts. A nonlinear elastoplastic type spud-can-soil interaction model is also applied. Loose sand to medium dense sand profile is considered at the sea-base. The effects of ship collision parameters such as ship mass and velocity, impact direction, hit point on jack-up as well as the spud-can-soil interaction are studied. For the first time, the supply vessel impact energy level far beyond 14 MJ as conventionally applied for ship-jack-up leg collision analysis (i.e., higher energy impact) has been also considered. The findings of this study indicated that the type of bow or broad-side impact as well as the spud-can-soil interaction may have considerable effects on the nonlinear dynamic behavior of the jack-up platform during ship collision. It is also found that ship collision in the direction of incident waves with mass of 5000 tons and impact velocity of 5 m/s displacement may have more profound effect on global dynamic response of the jack-up platform near ultimate collapse. It is also found in this research work that dynamic postimpact behavior of the jack-up platform may be greatly influenced by the combined action of extreme wave and current.