Sensitivity analysis of key parameters on static stiffness of the power umbilical

Abstract

The power umbilical is mainly composed of several unbonded spiral layers with high axial strength and flexibility in bending. In order to analyze the influence of the key parameters on the static stiffness of the power umbilical, a three-dimensional (3D) finite element method (FEM) model was developed through the program ANASYS where the modeling method showed an improvement over the other studies. Based on the model, the contact and friction between layers were taken into consideration, and the results were calibrated by the present theoretical results and experimental results. In addition, the parameter sensitivity analysis was carried out from the views of friction coefficient, lay angle and external pressure. The results show an obvious correspondence between the model and the published solutions, which means that the FEM model can describe the static stiffness of the power umbilical accurately. It is also shown that the lay angle of the wires will affect the tensile and torsional stiffness of the power umbilical to a large extent while the bending stiffness is mainly sensitive to friction coefficient. The achievements of this study can provide technical support for the section design and optimization of the power umbilical.