Two-Dimensional Dynamic Analysis of an Ocean Umbilical Cable Using the Geometrically Exact Beam Elements

Abstract

We present an idea for modeling flexible ocean umbilical cable using a nonlinear finite element method. The umbilical cable is assembled by Reissners geometrically exact beam elements, which take account of the geometric nonlinearities of large rotation and displacement, and effects of axial load and bending stiffness for modeling of slack cables. The linearization and discretization of the entire weak form for the umbilical cable system are proposed. The resulting semi-discrete motion equations are solved by the Newmark method. The capability of considering the action of horizontal ocean current is a key feature of this analysis. An example about the two-dimensional dynamic behavior of the umbilical cable system in depth-dependent ocean current with sinusoidal ship motion is presented.