Indexed by:期刊论文

Date of Publication:2015-03-01

Journal:APPLIED OCEAN RESEARCH

Included Journals:SCIE、EI

Volume:50

Page Number:58-68

ISSN No.:0141-1187

Key Words:Unbonded flexible pipe; Helical armor wire; Bending stress; Finite element; Validity domain

Abstract:Unbonded flexible pipe is one of the important pieces of equipment in floating production systems for transport of oil and gas between floaters and subsea wells located in deep water. To assure safety over a long-term service period, analysis of fatigue behavior under alternative bending is a key requirement. An analytical model for prediction of bending behavior is essential for understanding the mechanism of the local stress distribution in the helical wires of the tension armor layers under alternative curvatures and rapid estimation of the service life of flexible pipes for designers in engineering practice. In this paper, seven analytical models available in the literature are selected and summarized. Although the experimental results reported in the literature are limited, a three-dimensional finite element model is developed for investigation of the seven models, and the validity and limitations of these models for different structural Parameters of helical wire are discussed, i.e., the width-thickness ratio of the wire section and helical angle. The analytical model based on spring theory resulted in a satisfactory estimation of bending stress for most cases and is recommended as a tool for the basic design of the helical armor wire structures in flexible pipes. (C) 2015 Elsevier Ltd. All rights reserved.