THE EFFECT OF FIBER SIZING ON FIBERS AND BUNDLE STRENGTH IN HYBRID GLASS CARBON-FIBER COMPOSITES

Tests have been carried out on single carbon fibres supplied in the si zed and unsized conditions, as well as impregnated tows and tows in a glass-carbon fibre hybrid composite of the same fibre. The results wer e analysed using a Weibull distribution for the strengths of the reinf orcing fibres and composites. The tensile strength of the single fibre s appeared to be unaffected by the sizing of the filaments. In the cas e of the impregnated tows, an increase in characteristic strength of 7 % was observed for the unsized fibres. The strength of the impregnated tows in hybrid composites was seen to be 15% higher than those tested in air. This can be attributed to the ''hybrid effect''.