Fibre/resin interaction in fragmentation tests: coaxial vs. simple specimens comparison

Abstract

Fragmentation tests of single carbon fibres embedded in small resin specimens are widely used to compare fibre surface treatments or sizes. A limitation of the test is that the matrix must have a high enough ultimate strain for the multiple fracture process to be fully achieved before specimen fractures. The so‐called coaxial geometry was introduced in order to extend the method to low strain‐to‐failure resin systems. In agreement with the Cox theory of the elastic stress transfer, interposition of a ‘high’‐modulus material between the fibre and the resin (the ‘low’‐modulus material) results in a shorter fragment length, i.e. a better stress transfer.