Analysis Of Mechanical Properties Of Umbilical Spiral Carbon Fiber Reinforced Rod

Umbilical is the “Nerve Lifeline” connecting underwater production system and floating structure.With the advancement of the deepwater development of offshore oil and gas resources,the weight of steel pipelines restricts the development process of deepwater oil and gas.Using spiral carbon fiber reinforced rod instead of the steel armored layer in the umbilical to achieve a lightweight design of the umbilical.And it can effectively solve the contradiction between carrying capacity and self weight of the umbilical cable in the deepwater oil and gas development process.In this paper,the mathematical analysis method is used to analyze the geometrical model of spiral carbon fiber reinforced rod.It is found that the establishment of the parametric equation of its ideal contact model requires the determination of four specific parameters.Using anisotropic carbon fiber materials,taking into account the radial contraction and the assembly pressure effect,the stiffness matrix of the spiral carbon fiber reinforced rod under the tension-torsion coupled load is deduced through mathematical analysis and finite element calculation.It is found that the results of various stiffness coefficients obtained by mathematical analysis are closed to the finite element calculation.With the same structure size,the stiffness coefficient of the spiral carbon fiber reinforced rod is slightly smaller than that of the steel spiral reinforcement rod,but its weight is only about 1/5 of the latter.The integral form of carbon fiber reinforced umbilical is determined preliminarily,and the overall mechanical properties and hydrodynamic analysis of umbilical are carried out.It is found that the carbon fiber reinforced umbilical performed better than the steel armo red umbilical in mechanical properties,and it can completely satisfy the hard working environment of the water depth below 2700 m.The paper provides a theoretical basis,and carries out a preliminary exploration of practical applications for the lightweight design of deepwater umbilicals,which promotes the process of development of deepwater oil and gas.