Strength studies of single carbon fibres in model composite fragmentation tests

Abstract The strength of single fibres embedded in resin has been estimated by continuous monitoring of single embedded-fibre fragmentation tests. The data generated have been analysed using an adapted Weibull model which includes the influence of the ‘ineffective’ length at each fibre break. Weibull parameters determined from this analysis have been compared with those from tests carried out on fibres in free air. Similar trends were observed. Estimates of interfacial shear strength can also be generated from the fragment lengths and embedded-fibre strengths, and these values together with the strength data indicate an optimum treatment level which may have occurred after the removal of a weakly bonded layer of graphite on the surface.