The influence of binder tow density on the mechanical properties of spatially reinforced composites. Part 2 - Mechanical properties

As a continuation of previous work [McIlhagger R, Quinn J, McIlhagger A, Wilson S, Simpson D, Wenger W. The influence of binder tow density on the mechanical properties of spatially reinforced composites. Part 1 - impact resistance. Composites Part A 2007;38:795801], this paper examines the mechanical properties of advanced spatially Reinforced Composites (SpaRC). Complex multi-axis, multilayer reinforcements were produced with a range of binder tow stitch densities on a specially developed loom and these samples were impregnated with an aerospace certified epoxy resin system (RTM6) using a resin transfer moulding process. The mechanical properties of the resulting composites were assessed using standard flexural, inter-laminar shear, open-hole tension and compression after impact tests. It has been shown that as the binder tow stitch density was increased, the compression after impact strength also increased while the inter-laminar shear properties were relatively unaffected. It is also shown that the flexural and inter-laminar shear properties were influenced by the composite reinforcement architecture, the proximity of the 0 degrees and 90 degrees layers with respect to the neutral axis and specifically the presence of the +/- 45 degrees (off-axis) tows affects overall performance in flexural and ILSS loading. (c) 2007 Elsevier Ltd. All rights reserved.