Approach to net-shape preforming using textile technologies. Part II: holes

Considering cost-effective fibre-reinforced plastic (FRP) parts manufactured by resin transfer moulding (RTM) technologies, net-shape preforms can contribute to mechanical post treatment free manufacturing, hence reducing cycle-time and cost. In addition to this, RTM specific problems, such as fibre pinching when closing the tool can be avoided. The wide range of textile technologies used for FRP parts offers various possibilities to achieve net-shape parts within the preforming process including bores or inserts (see part II). The potential of the presented technologies is evaluated and discussed. Apart from standardised testing methods, a new side-impact testing was specially designed for determining the in-plane damage-tolerance of net-shape manufactured FRP parts. Folding to net-shape shows poor quality but improves mechanical properties. Rim-protections with braided inserts or over-edge stitching technologies which provide exact preform dimensions, improved mechanical performance. Especially side-impact tolerance or in-plane damage tolerance was increased. Ultra-sonic testing was successfully applied to visualise the differences in damage tolerance and propagation between these new rim technologies.