Quantitative microstructural examination of RTM fabrics designed for enhanced flow

The resin transfer moulding (RTM) process involves the long-range flow of resin through a mould packed with dry reinforcement. The process can be considered as similar to the flow of fluids through porous media, and hence the situation can be modelled by the Darcy and Kozeny-Carman equations. The Kozeny-Carman equation predicts the effect of changes in the pore structure of the reinforcement on flow rate, through a parameter known as hydraulic radius, which is itself a function of the wetted surface in any given volume. Laminates have been manufactured, from fabrics which include flow-enhancing tows, in a transparent RTM mould. The cured laminates were sectioned for quantitative microscopy and image analysis. An analysis of the effect of substituting spiral-wound flow-enhancing tows for conventional tows in the reinforcement fabric is presented.