Forming discontinuous fiber arrays by fracture of lubricated carbon-filament tows

This paper presents the results of a set of continuous-filament-tow fracturing experiments designed to produce highly collimated discontinuous-fiber-arrays with well-dispersed fractures. Discontinuous-fiber-arrays have at least two uses: reinforcing a matrix phase at high volume fraction and, when impregnated with a fluid, performing as a microrheometer. The lubricating fluid used for these experiments is uncured TCR epoxy, which may be stored at room temperature for up to one year. Tows with gauge lengths of 287, 362 and 400 mm were fractured into discontinuous fibers arrays during extension at four percent strain/min. Weibull analysis showed singlet failures were responsible for the fracture process of the two largest gauge length samples and multiplet failures accounted for the bulk of fracture at the shortest gauge length. Normal distributions approximated the filament length distribution at all gauge lengths. The longest gauge sample had the best distribution of filament breaks and had an average fiber length of 207 mm and a standard deviation of 65 mm.

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