CHARACTERIZATION OF FIBERS - IMPROVEMENT OF THE LOOSE BUNDLE TEST BY DIRECT MEASUREMENT OF THE STRAIN

The statistical variation in mechanical properties of E-glass fibres h as been studied using loose bundles containing N greater than or equal to 1 000 fibres. Particular care has been taken for preparation of th ese bundle specimens so as to be able to measure the direct sample def ormation with a mechanical extensometer. The direct measure of the bun dle strain during a tensile test allows us to obtain a reliable determ ination of the intrinsic. 'load-strain' behaviour law and of the follo wing characteristics of the bundle: number of initially intact fibres in the bundle; Weibull shape parameter strength and failure strain of the bundle and mean strength of the fibres.