Simulation of the fibre fragmentation process by a fracture mechanics analysis

A computer simulation model has been developed to investigate the fibre fragmentation process in a single-fibre model composite. The breakage of the fibre was assumed to be controlled by the critical stress intensity factor of pre-existing flaws on the fibre surface, the size of which follows either a random distribution or a Pareto distribution. A Griffith energy-balance theory is used to establish the interfacial debond criterion. The simulation results of mean fibre fragment length and mean fibre fragment debond length versus applied stress are presented for a carbon-fibre/epoxy-matrix composite with two different fibre surface treatments. The effects of flaw density and flaw size on the fragmentation process and mean fibre fragment length are discussed with respect to flaw distribution. The present results contribute to a better understanding of fibre fragmentation mechanisms in fibre-reinforced composites.