Hybrid composite wires for tensile armours in flexible risers: Manufacturing and mechanical characterisation

Abstract

With the rising global demand for hydrocarbon fuels, there is a growing need for the oil and gas industry to operate in deeper offshore waters. In this context, the traditional metallic tensile armours in flexible risers pose certain limitations (e.g. weight, corrosion, fatigue damage) in demanding service environments. This paper presents a novel and proprietary hybrid composite wire as an alternative to metallic (carbon steel) wires. The hybrid composite wire consists of an over-braided (Dyneema® 1 fibres) core, with the core consisting of hexagonally packed composite rods (pultruded carbon fibre and vinyl ester). These hybrid composite wires can provide high tensile strength and stiffness accompanied by low flexural and torsional rigidities, which can easily be tailored by varying geometrical and manufacturing parameters. This paper presents the manufacturing methods used, and the mechanical behaviour of the hybrid composite wires with various configurations.

Hybrid composite tensile armour wires in flexible risers: A multi-scale model

“…using a micro-mechanical model) and the overbraid sleeve (i.e. using a meso-mechanical model, which is based on the model proposed for a tri-axial braids in [1]), are used to develop a multi-scale model for the hybrid composite wires. The internal friction between composite rods as well as the rods and the shell (i.e.…”

“…The procedure followed for the manufacturing and testing of the hybrid composite armour wires is reported by the authors in Gautam et al [1]. The manufacturing process of the hybrid composite wires involved overbraiding of hexagonally packed pultruded rods, where each rod had a diameter of 4 mm.…”

“…The torsion tests, with a gauge length of 100 mm, are carried out up to a maximum limit of 400 º/m for the hybrid wires [1]. A total of 5 specimens for each configuration (see Table 1 …”

“…The structure is analogous to the structure of flexible riser itself, comprising of multiple un-bonded components. This paper, with emphasis on computational modelling, is an extension to the experimental work conducted by the authors in Gautam et al [1]. A multi-scale model is developed by using a combined analyticalcomputational approach for the hybrid composite armour wires to study the torsional and flexural behaviour as a function of over-braid parameters, internal friction, and braid tow pre-tension.…”

“…1) is proposed by Gautam et al [1]. These hybrid composite armour wires consist of carbon and vinyl ester pultruded rods, stacked in form of hexagonal closed packing, completely un-bonded to each other, but held together by an over-braided ultrahigh molecular weight polyethylene (UHMW-PE) fibres-commercially known as Dyneema.…”