FIBER STRAIN MAPPING IN ARAMID EPOXY MICROCOMPOSITES/

Two-dimensional microcomposites, comprising regular arrays of Kevlar 4 9 fibres embedded in an epoxy resin, were fabricated and subjected to incremental tensile loading up to fracture. The strain along individua l fibres at different levels of applied load was monitored using a las er Raman spectroscopic technique. A strain magnification of 80% maximu m was measured in an intact fibre as a result of a fibre fracture in a n adjacent fibre. The exact distribution of the strain increase within the transfer length of the broken fibre was obtained. The experimenta l stress concentration factor is compared with that derived from exist ing analytical models.