Theoretical Analysis And Numerical Simulation On The Mechanical Property Of Marine Dynamic Pipe Line

Marine pipe line system is one of the important structures in the offshore oil and gas development. Umbilical cable system is the most important type of the marine pipe line system and it plays a huge role for offshore oil and gas development, so its mechanical properties are focused for every researcher. In this paper, the local mechanical properties of the umbilical cable are analyzed theoretical analysis and simulated numerical calculation by ANSYS in detail. The purpose is to provide theoretical guidance for actual engineering design.Firstly, mechanical properties of marine pipe lines in section stiffness and strength is introduced in detail. This provides a clear structure concept for the following ANSYS numerical simulation. The single spiral line mechanical properties of tension-torsion are discussed, which is help for understanding and applying the umbilical cable tension-torsion theoretical model. Due to the umbilical cable composed of multilayer material, contract analysis is indispensable part for mechanical numerical analysis. Those are summarized of analysis steps and cautions about ANSYS contract analysis. The best of elements are selected for contract analysis by an comparison of different elements in the same example.Secondly, the tension stiffness and bending stiffness of unarmored steel umbilical cable are calculated in theoretical analysis and numerical simulation and those results are also compared. Point and point contract analysis is used of numerical simulation of ANSYS. The theoretical and numerical results are in good agreement within a certain error range about axial tension stiffness when those have the same boundary conditions. When the angle of spiral lines becomes larger, the axial tension stiffness of the umbilical cable becomes less and it becomes bigger when the coefficient of friction becomes bigger. The numerical simulation model is closer to actual working conditions by the analysis of the different boundary conditions. For analysis of the bending stiffness, the numerical analysis is little errors compared to theoretical analysis before slippage occurs between the spiral lines. However, when the slippage has occurred, the bending stiffness of numerical analysis deceases rapidly.Finally, the tension stiffness bending stiffness and torsion stiffness of armored steel umbilical cable are researched by numerical analysis and their result is compared to one of theoretical analysis. The method that we own definite beam section in BEAM189element and apply to point and point contract analysis is used for the numerical simulation of ANSYS. The theoretical and numerical results are in good agreement within a certain error range about axial tension stiffness. By the numerical simulation analysis, armored steel wires are the main force components when armored steel umbilical cable is forced tension loads. The bending stiffness of it is larger errors compared to theoretical analysis when the angle of spiral lines is little. But with the angle of it becomes larger, the errors become less. The stress of internal pipes are, larger than one of armored steel wires when armored steel umbilical cable is forced bending loads and internal pipes get yields more easily. When the friction coefficient of pipe lines and the angle of spiral lines become larger, the torsion stiffness becomes larger by the numerical simulation of torsion deformation.