Carbon Fibres: Manufacture, Properties, Structure and Applications

Johnson, D. J.

doi:10.1016/b978-0-408-03837-9.50011-7

Cited by 4 publications

(1 citation statement)

References 33 publications

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“…This is due to their atomic structure 6 . Essentially, PAN-based carbon fibres are nongraphitizing with a turbostratic (irregular) organisation of the graphitic layer planes, and the most realistic model of the structure consists of a complex fibrillar structure threedimensionally interlinked forming crystallites which enclose sharp-edged voids 7 . In E-glass type fibres the presence of elements such as Ca, Na and K tends to break up the regular network of the three-dimensional covalent bonded tetrahedral formed in the presence of silicon, at the centre, and oxygen at the corners.…”

Section: Resultsmentioning

confidence: 99%

Influence of the Testing Gage Length on the Strength, Young's Modulus and Weibull Modulus of Carbon Fibres and Glass Fibres

Pardini

Manhani

2002

Mat. Res.

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Carbon fibres and glass fibres are reinforcements for advanced composites and the fiber strength is the most influential factor on the strength of the composites. They are essentially brittle and fail with very little reduction in cross section. Composites made with these fibres are characterized by a high strength/density ratio and their properties are intrisically related to their microstructure, i.e., amount and orientation of the fibres, surface treatment, among other factors. Processing parameters have an important role in the fibre mechanical behaviour (strength and modulus). Cracks, voids and impurities in the case of glass fibres and fibrillar misalignments in the case of carbon fibres are created during processing. Such inhomogeneities give rise to an appreciable scatter in properties. The most used statistical tool that deals with this characteristic variability in properties is the Weibull distribution. The present work investigates the influence of the testing gage length on the strength, Young's modulus and Weibull modulus of carbon fibres and glass fibres. The Young's modulus is calculated by two methods: (i) ASTM D 3379M, and (ii) interaction between testing equipment/specimen The first method resulted in a Young modulus of 183 GPa for carbon fibre, and 76 GPa for glass fibre. The second method gave a Young modulus of 250 GPa for carbon fibre and 50 GPa for glass fibre. These differences revelead differences on how the interaction specimen/testing machine can interfere in the Young modulus calculations. Weibull modulus can be a tool to evaluate the fibre's homogeneity in terms of properties and it is a good quality control parameter during processing. In the range of specimen gage length tested the Weibull modulus for carbon fibre is ~ 3.30 and for glass fibres is ~ 5.65, which indicates that for the batch of fibres tested, the glass fibre is more uniform in properties

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Section: Resultsmentioning

confidence: 99%