Response Characteristics Of Subsea Manifold Installation Based On Multi-body Coupled

In the process of using the engineering ship to lower and install the subsea manifold,the operation safety is seriously endangered due to factors such as strong nonlinear environmental load and ship heave motion.Studying the dynamic response characteristics of the multi-body coupled installation process of the subsea manifold is the core issue to ensure its safe decentralization.In this thesis,the second-order linear differential equations are used to describe the rocking motion response of the engineering ship,and the transformation matrix between each link is calculated by referring to the motion analysis method of the manipulator.The motion models of the boom of the engineering ship under the conditions of roll,pitch and roll and pitch are calculated respectively.Using the moment balance equation and displacement continuity equation of the micro-element section of the steel cable,the shape and force equations of the steel cable at different times are deduced.Combined with the dynamic equation and force analysis of the subsea manifold,a spatial six-degree-of-freedom motion model of the system of the subsea manifold is constructed,and the numerical analytical solution is obtained.The multi-body coupled model of the engineering ship-steel cable-subsea manifold is established,aiming at the environmental parameters(wave angle,wave height and period,current velocity,fluid density),steel cable parameters(Young’s modulus,Poisson’s ratio,drag coefficient),the parameters of the subsea manifold itself(center of gravity,center of buoyancy)and the lowering speed,revealing the change law of the motion response and installation attitude of the subsea manifold during the lowering process.By establishing the force analysis model of the guide pile coupled system between the subsea manifold and the suction anchor,the dynamic response characteristics of the main body of the subsea manifold in the seabed docking process are explored,the topping and detachment phenomena are explained,and the strength of the guide pile is checked.The research results can provide reference and guiding significance for practical engineering such as wire cable lowering and docking installation of subsea manifold.