The Analysis of Mechanical Properties and Lightweight Design of Nonmetallic Armored Umbilical Cable

Abstract

Due to the development of gas and oil exploration into the deep sea, the effective tensile capacity provided by armored steel wire will decrease rapidly with the increase of the weight of umbilical cables. In this paper, two designs of lightweight umbilical cables were studied in full consideration of the geometric characteristics, and the mechanical properties were investigated under tension, bending, and torsion. The contact and friction between the components of the umbilical cables were also included in the model. Three cases are presented for validation from theoretical and finite element methods. The discussion on variables was carried out from the views of friction coefficient and helically wound angle. Compared with the steel tube umbilical model, the nonmetallic armored umbilical cable shows higher tensile strength and more flexibility. With the increase of friction coefficient, the stiffness of umbilical cable models doesn't change much. The helically wound angle has a great influence on the tensile stiffness and bending stiffness but little effect on the torsional rigidity. The proposed lightweight model can be applicable to 6000 m water depth. This research can benefit the design of umbilical cables to achieve the goal of high tensile capacity in deepwater applications.