The local bond strength and its determination by fragmentation and pull-out tests

Several theoretical models have been analysed to determine the local (ultimate) adhesive bond strength for a thin-fibre/thermoplastic-matrix system, proceeding from experimental data obtained by the fragmentation and pull-out techniques. For the pull-out test, an extrapolation model is proposed that takes into account the stress in a matrix resulting from both external load and thermal shrinkage. For the fragmentation technique, the local adhesive strength was calculated from the results of continuously monitored single-fibre composite tests. Both approaches gave close ultimate bond strength values for carbon-fibre/epoxy-matrix systems. (C) 1997 Elsevier Science Limited.