Study On The Collision Problem Of Jack-up Platform Legs Docking On The Sea

The jack-up drilling platform is the most common mobile offshore drilling platform.Among them,the most important component of jack-up platform is pile leg,and the commonly used methods for lifting the legs are lifting method of dock and hoisting at sea.The hoisting method at sea is suitable for lifting piles with big weight and large length.The lifting work under complex environmental conditions,often encounter all sorts of unexpected circumstances,collision phenomenon is a kind of when an accident happens;collision at sea legs in the docking process may cause serious accidents.Therefore,it is of great significance to avoid the risk and reduce the loss when analyzing and studying the collision problem in the butt joint operation of the pile leg.This paper takes the JU2000 E jack-up drilling platform as an object,and the basic equation of motion is established by Lagrange method to solve the platform collision problem.According to the collision theory,a local finite element model of jack-up platform is established by using large nonlinear finite element analysis software ANSYS/LS-DYNA.Simulate the crane under different speed on the platform side of the low-speed collision phenomenon,legs at different height falls on the platform of helicopter deck slamming,and legs to move at different speeds on the platform of the superstructure low-speed collision phenomenon.Analysis of the impact in the process of platform of energy change,crane or leg speed change,platform deformation and stress change and structure failure etc..According to the results,the relationship between the maximum stress of the platform and the collision velocity is obtained,and then the critical collision velocity of the platform in different regions is given.Then,analyze the process and factors of sea legs may cause the problem of collision docking,and based on the simulation results of the collision damage,according to the influencing factors of collision and leg offshore lifting limit conditions in the process of sea legs,the docking process in place and crane operations and leg lifting process optimization.This paper gives a brake crane in place of the distance,the safe distance of leg lifting hoisting height in the process of decentralization and the speed limit,and in the process of moving and superstructure and the moving speed limit.It provides reference for the design of the lifting operation scheme of the leg.