An investigation into the effects of fabric architecture on the processing and properties of fibre reinforced composites produced by resin transfer moulding

The use of resin transfer moulding (RTM) as an economic and efficient means of producing high performance fibre-reinforced composites is critically limited by the permeability of the fabrics employed. Commercial fabrics are available where the architecture of their reinforcement is designed to cluster the fibres, giving higher permeabilities than conventional fabrics. This has been shown to improve processing times, but there is evidence that such clustering is detrimental to the mechanical performance of the resulting composite materials. The objective of this work was to relate variations in permeability and mechanical performance to differences in composite microstructure. This was achieved by producing carbon/epoxy plates of different weave styles by RTM in a transparent mould. The progress of the resin was recorded by a video camera during injection, and the images were processed by a frame-grabbing computer, permitting the permeabilities of the fabrics to be calculated. Further plates were manufactured using the same fabrics, and sectioned for microstructural image analysis and interlaminar shear strength (ILSS) testing to CRAG standards. Relationships were sought between measured permeabilities and finished microstructures using a Quantimet 570 automatic image analyser. It has been shown that variations in permeabilities and mechanical properties can be related to observed differences in the microstructure. (C) 1997 Elsevier Science Limited.