On the influence of pre-stress on the mechanical properties of a unidirectional GRE composite

The effect of composite pre-stress on the mechanical properties of E-glass fibre in an epoxy resin has been investigated theoretically and experimentally. Experimental results have been obtained for pre-stresses (0, 25, 50, 75, 100, 200 MPa) at each of three fibre volume fractions (0.35, 0.45, 0.6). A theoretical model has been developed to predict the effect of composite pre-stress on the pre-load strain in fibre and matrix, tensile strength and elastic modulus of the composite. The results show that pre-tensioning of the fibre during fabrication increases the tensile strength and elastic modulus of the composite. This increase has been found to be a function of composite pre-stress and fibre volume fraction. Good agreement has been obtained between the theoretical results and experimental measurements.