Study Of Efficient Solution To Dynamic Problems Of Mooring Line Based On Rod Theory

After years of development, the finite element method based on slender rod theory has been employed to analysis of mooring line system widely.The mooring line is considered as a continuous elastic medium composed of many units and the spatial configuration and tension distribution can be accurately expressed by using the interpolation function to expresss variables with node values.In this paper,the finite element method is employed to disperse the governing equations of the mooring line and program has been writen for static and dynamic analysis.A series of case study are carried out to verify the effectiveness of the program.The top of the mooring line is supposed to be hinged to the fairleads.A great deal of attention has been paid to the ocean bottom boundary condition.The ocean bottom is assumed to be flat and elastic and it is reasonable to use an elastic layer composed of nonlinear springs to represent the ocean bottom . Newton's method is used to solve the static problems ,and the influence of axial stretch and hydrostatic pressure is studied. For dynamic problems two different integral format are employed :Adams-Moulton format and Newmark-pformat.The accuracy ,efficiency and stability are compared between them.Combining with asynchronous coupling method to mooring system and platforms,the MPI paralleling computing technology is adopted to improve the computation efficiency of dynamic analysis.