Research On Simulation Technologies Of Ship Pipelaying Operation

Subsea pipelines play an important role as a lifeline to the exploitation of ocean resources.The installation of subsea pipelines faces extraordinary challenges due to the complex construction environments and high requirements for the construction quality.By pipelaying operation simulation method,the personnel operational experiences can be improved,and the assignments can be previewed and evaluated,so the risks of actual offshore operation will be reduced,and the safety will be improved.In this dissertation,an investigation was performed to study the key technologies of vessel pipelaying operation simulation method:the dynamic geometry nonlinearity problem of subsea pipeline installation was analyzed based on the small strain,large displacement elastic beam model and the nonlinear finite element analysis method,and using the catenary curve as the initial shape,the force and deformation analysis of pipelines was performed by iterative computations;the kinematic and dynamic model based on multi-rigid-body theory was established to study the dynamic real-time simulation problem;a PSR-DSRvSVR-NCEBA ship motion prediction method was proposed considering the time series of ship motions;a framework of pipelaying operation simulation system was designed and built.The contents of the dissertation include:1)Studied the stress-strain relation of pipelines by analysis of static and dynamic force balance equation based on the small strain large displacement theory for geometry-nonlinear Euler-Bernoulli beams and obtained the tangent non-stiffness matrix for small strain and geometry-nonlinear beams;solved the static nonlinear finite element balance equation using the combined Newton-Raphson iterative and load increment method;used linear time domain integration method to solve dynamic nonliear FEM equation,reduced the iterative computation by describing the deformation motion with the Updated Lagrange method and setting the catenary curve as the initial shape.2)Established the multi-rigid-body kinematic and dynamic models for pipelines with the rigid body element and the generalized displacement and velocity of hinges based on the multi-rigid-body system theory and the Lagrange expression coordinates,and analyzed the mass matrix,damping matrix,deformation force vector etc.Solved the top tension of pipeline using inverse method,which can be used as an input of tensioner,and made essentially support to real time simulation of deep-sea pipelaying operations.3)Aiming at the chaotic and periodicly ship motion time series data,which has noisy disturbance,this paper studied this prediction sapce reconstruction method(PSR),and to enhance the robust adaption to time serial variation,this paper proposed a dynamics seasons adjusted model(DSAM),and combined it with Robust-v Support vetor machine(RvSVR),and finally constructed a PSR-DSRvSVR prediction model.Aiming at the shortcoming of bat algorithom,this paper combined cat mapping,and cloud model as well as nicle acceleration searching method together and produced a high niche chaos efficient bat algorithm(NCEBA),and used it to the knotty problem of DSRvSVR parameters optimization,so the whole algorithm named PSR-DSRvSVR-NCEBA prediction method was established for ship heaving motion,which can rapidly predict the ship motion with accuarcy and robust,as well as reflect the chaos of ship motion in time series,and effectively response to the noisy signals problem.4)Estabilish a simulation framework and software data change port of pipelaying operation system,design a PID logic tensioner controller and drive model,and the tensioner can output tension realtimely.Based on these results,this paper also make a simulation test,and use it in the key technical problems for installation of deep water pipelines using a simulation method,contribute the core technical to "pipelaying and crane ship and supporting technology",a sub-topic of the National Science and Technology Major Project.