Multiple fracture in a steel reinforced epoxy resin composite

Abstract

Specimens of an epoxy resin reinforced by steel wires have been made to fail by a process which involves extensive cracking of the matrix before the UTS of the composite is reached. Such behaviour can result in energy being absorbed by the composite under constant or rising load conditions even when the composite is composed of two brittle phases. The influence of fibre size and volume fraction on the cracking process have been examined, and it has been shown that for low fibre volume fractions and large fibre sizes, the cracking process is governed by a simple relationship. When the fibre size becomes small, or the volume fraction becomes large, the cracking process is hindered, and this relationship breaks down. Under extreme conditions, cracking of the matrix can be completely suppressed and the matrix can be forced to exhibit properties markedly better than it would have shown when tested by itself. The design of materials which behave in this way may provide an important means for producing ceramic-matrix compositions with very good mechanical properties.