Resin-rich volumes ( RRV ) and the performance of fibre-reinforced composites: a review

This review considers the influence of Resin-Rich Volumes (RRV) on the static and dynamic mechanical and physical behaviour of fibre-reinforced composites. The formation, shape and size, and measurement of RRV in composites consequent upon different fabric architectures and manufacturing processes is discussed. The majority of studies show a negative effect of the RRV on the mechanical behaviour of composite materials. The main factors that cause the RRV are (a) the clustering of fibres as bundles in textiles, (b) the stacking sequence, (c) the consolidation characteristics of the reinforcement, (d) the resin flow characteristics as a function of tempera-ture, and (e) the composite manufacturing process and cure cycle. RRV are stress concentrations that lead to a disproportionate fall in composite strength. Anyone considering moving from autoclave consolidation to out-of-autoclave (OOA) processes should be cautious of the potential effects of the change.