A study of the effects of convergent flow fronts on the properties of fibre reinforced composites produced by RTM

The processing speed of resin transfer moulding (RTM) can be improved by using multiple injection ports. Out of necessity this results in the convergence of resin flow fronts. Such convergence can result in the entrapment of voids within the composite leading to a degradation of mechanical properties. A series of carbon/epoxy plates of differing weave styles were manufactured by RTM in a transparent mould with porting arrangements designed to cause resin flows to converge. The plates were analysed to determine the effect of injection strategy, injection temperature and differences in weave style. Analysis was performed by qualitative ultrasound scanning, quantitative image analysis and interlaminar shear strength testing. It has been shown that there is a marked increase in voidage in the areas where hows meet and this is correlated to a deterioration of mechanical properties. (C) 1997 Elsevier Science Limited.