Handbook of fibre rope technology

McKenna, H.A.; Hearle, J. W. S.; O'Hear, N.

doi:10.1533/9781855739932

Cited by 108 publications

(103 citation statements)

References 0 publications

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“…The resulting fiber has a fibrillar texture, but it is highly oriented and has the necessary high crystallinity and the chain-extended structure to give it high modulus and high strength greater than those of the flexible semi-crystalline polymer fibers. The elongation of the resulting fiber here is low 17,24,33 . The modulus of the PPTA fibers is essentially independent of the inherent viscosity and the air gap.…”

Section: Spinning Processmentioning

confidence: 84%

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Microstructural developments of poly (p-phenylene terephthalamide) fibers during heat treatment process: a review

et al. 2014

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Poly (p-phenylene terephthalamide) fibers prepared by wet or dry-jet wet spinning processes have a notable response to very brief heat treatment (seconds) under tension. The modulus of the as-spun fiber can be greatly affected by the heat treatment conditions (temperature, tension and duration). The crystallite orientation and the fiber modulus will increase by this short-term heating under tension. Poly (p-phenylene terephthalamide) fibers have a very high molecular orientation (orientation angle 12-20°). Kevlar  and Twaron  fibers are poly (p-phenylene terephthalamide) fibers. This review reports for PPTA fibers the heat treatment techniques, devices and its process conditions. It reports in details the structural relationships between the fiber properties which are influenced by the heat treatment process. In particular, focused deeply on the effect of the crystal structure and the morphology of the fibers on the mechanical properties of PPTA fibers.

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Section: Spinning Processmentioning

confidence: 84%

“…The layer of the hydrogen-bonded chains and the contents of the cell are shown in Figures 9a Figure 9. The PPTA crystal lattice with pseudo-orthorhombic unit cell 33,34 . and b: (a) the projection of the crystal structure parallel to the a-axis of a layer of hydrogen-bonded chains and (b) is the projection parallel to the c-axis.…”

Section: Crystal Structurementioning

confidence: 99%

Microstructural developments of poly (p-phenylene terephthalamide) fibers during heat treatment process: a review

et al. 2014

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“…Whilst load overshoot would have had some in uence on the rst few cycles of each harmonic interval, the measured responses suggest that the accumulated strain of the rope by the nal cycles was not greatly in uenced. As the properties of synthetic materials including nylon can be in uenced by uctuations in the surrounding environment [17], measurements of air temperature were made continuously during testing for load set LS2. The humidity level was also recorded at the start of each test (Table 4).…”

Section: Rope Testing Proceduresmentioning

confidence: 99%

Synthetic rope responses in the context of load history: Operational performance

et al. 2014

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The utilisation of synthetic mooring ropes for marine renewable energy (MRE) devices is a recent occurrence. Despite current use in the o shore industry, MRE mooring components are typically subjected to highly dynamic loads, necessitating the detailed characterisation of operational and long-term component performance for lifecycle analysis and operations management. To address the uncertainties associated with synthetic mooring components in this application, tension experiments have been conducted on nylon 6 parallel-stranded rope samples at IFREMER, France and the University of Exeter, UK under the consortium MERiFIC (Marine Energy in Far Peripheral and Island Communities). Measurements are reported from harmonic loading tests with di erent initial bedding-in levels used to investigate the in uence of load history on the immediate dynamic properties of the rope. Two irregular load regimes were also applied based on mooring tensions recorded by the South West Mooring Test Facility (SWMTF). Datasets are provided to facilitate the development of rope modelling tools. For the load regimes studied it was found that the operational performance of the rope is strongly in uenced by the instantaneous load-strain characteristic. This study provides unique insight into the sti ness and damping properties of synthetic rope in the context of loading regimes relevant to MRE devices.

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“…Conventional fibre ropes display hysteresis when subjected to cyclic loading, a proportion of the work done during the extension being transferred to heat [13]. This is an important consideration for both conventional ropes and the Exeter Tether (which also displays hysteretic behaviour) as the hysteresis will contribute to the damping of the system.…”

Section: Introductionmentioning

confidence: 99%

A Novel Mooring Tether for Highly-Dynamic Offshore Applications; Mitigating Peak and Fatigue Loads via Selectable Axial Stiffness

Gordelier

Parish

Thies

et al. 2015

JMSE

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Highly-dynamic floating bodies such as wave energy convertors require mooring lines with particular mechanical properties; the mooring system must achieve adequate station keeping whilst controlling mooring tensions within acceptable limits. Optimised compliant mooring systems can meet these requirements but where compliance is achieved through system architecture, the complexity of the system increases together with the mooring footprint. This work introduces the "Exeter Tether", a novel fibre rope mooring tether providing advantages over conventional fibre ropes. The tether concept aims to provide a significantly lower axial stiffness by de-coupling this attribute from the minimum breaking load of the line. A benefit of reduced axial stiffness is the reduction of mooring system stiffness providing a reduction of peak and fatigue loads, without increasing mooring system complexity. Reducing these loads improves system reliability and allows a reduction in mass of both the mooring system and the floating body, thus reducing costs. The principles behind the novel tether design are presented here, along with an outline of eight prototype tether variants. Results from the proof of concept study are given together with preliminary findings from sea trials conducted in Falmouth Bay. Results demonstrate that the Exeter Tether can be configured to achieve a significantly lower axial stiffness than conventional OPEN ACCESS J. Mar. Sci. Eng. 2015, 3 1288 fibre rope and that the stiffness is selectable within limits for a given breaking strength. Strain values greater than 0.35 are achieved at 30% of line breaking strength; this represents more than a threefold increase of the strain achievable with a conventional rope of the same material. The tether was subjected to six months of sea trials to establish any threats to its own reliability and to inform future design enhancements in this respect.

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Handbook of fibre rope technology

Cited by 108 publications

References 0 publications

Microstructural developments of poly (p-phenylene terephthalamide) fibers during heat treatment process: a review

Microstructural developments of poly (p-phenylene terephthalamide) fibers during heat treatment process: a review

Synthetic rope responses in the context of load history: Operational performance

A Novel Mooring Tether for Highly-Dynamic Offshore Applications; Mitigating Peak and Fatigue Loads via Selectable Axial Stiffness

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