Effects of interphase and impact strain rates on tensile off-axis behaviour of unidirectional glass fibre composite: Experimental results

Abstract

The effects of interphase and the strain rate on tensile behaviour of composite materials have been studies on epoxy reinforced by 10 and 40% volume fractions of glass fibre. The silane and the Polyvinylacetate (PVAC) with saline fibre coatings have been used. Under tensile loading (3 × 10 −3s −1 to 3 × 10 2s −1) at room temperature, the composite is observed to behave in a brittle manner over the entire strain range investigated. In the quasi-static domain, the maximum tensile stress is found to vary linearly with the log of the strain rate whereas at a high strain rate, this function seems to be a power function of strain rate. The Bingham-Norton's model group with Eyring's model seems to be suitable, in first approximation to describe the experimental failures. The off-axis tests point out the effect of the interphase and interface in unidirectional composite. It was shown by the SEM analysis that the presence of a third phase (PVAC) tends to affect particularly stress-strain behaviour in the high strain rate range.