FIBER STRAIN MAPPING IN ARAMID/EPOXY MICROCOMPOSITES

Two-dimensional microcomposites, comprising regular arrays of Kevlar 49 fibres embedded in an epoxy resin, were fabricated and subjected to incremental tensile loading up to fracture. The strain along individual fibres at different levels of applied load was monitored using a laser Raman spectroscopic technique. A strain magnification of 80% maximum was measured in an intact fibre as a result of a fibre fracture in an adjacent fibre. The exact distribution of the strain increase within the transfer length of the broken fibre was obtained. The experimental stress concentration factor is compared with that derived from existing analytical models.