Fracture of Fibre Reinforced Materials

Abstract

A SIMPLE experiment has been carried out which shows the importance of the rate of loading on the fracture characteristics of a unidirectional composite. Three specimens of flexibilized epoxy resin, 12.7 mm × 6.4 mm in cross-section and 50 mm test length reinforced with 3 volumes per cent continuous silica fibres in unidirectional array, were loaded to fracture at 0.051 mm/min, 5.1 mm/min, 510 mm/min respectively, at room temperature. Fracture was deliberately encouraged by forming a small notch at one side of each specimen and a tensile crack then spread in the resin to the opposite side. Fibre fracture did not coincide with resin fracture but was spread over a region on either side of the resin crack.