In the current study, the model, previously developed by Wilson, was reviewed and extended to predict the mechanically induced spreading of E-glass fiber bundles. The widths of the as-received E-glass fiber bundles were increased by 200–250% when subjected to a series of reciprocating motions. A 350–450% increase in the widths of the bundles was observed when the tension was released (tension-release mechanism) and the reciprocating motions repeated. The effect of the number of rods, angles and distances between them, and their relative geometry on the extent of fiber spreading was studied. The forces involved in fiber spreading are discussed using micro-mechanics involved in the fiber spreading.

This is a two-part paper where part 1 presents details of a modified wet-filament winding process. Here, the resin bath was replaced with a resin injection system that impregnated the fibres prior to winding them onto a rotating mandrel. The resin and hardener were stored in separate containers and pumped on-demand via a pair of precision gear-pumps to a static mixer. The mixed resin system was then supplied to a custom-designed resin impregnation unit. The theoretical basis for the design of the resin impregnation unit is presented along with simulations of the various parameters that influence the impregnation time and the degree of impregnation. Part 2 of this series papers presents the experimental data on the performance of the resin impregnation unit and a comparison of the physical and mechanical properties of the tubes manufactured using the conventional and modified wet-filament winding techniques.

This paper reports on a modified pultrusion process where the conventional resin bath was replaced with a customdesigned, enclosed resin impregnation unit. A feature of this modified production process is that the rovings were spread, prior to impregnation, using a compact fibre spreading unit. The resin impregnator was designed to accommodate 60 rovings of 2400 tex E-glass. The design features enabled specified modes of impregnation to be enacted including, resin-injection, pin-impregnation, capillary-impregnation and compaction. The impregnator was designed to accept pre-mixed resin from a pneumatically activated pressure-pot or a custom-designed resin delivery system. Pultrusion trials were conducted on a commercial machine using a conventional resin bath, the pressure-pot and the impregnation unit. The physical, mechanical and thermo-mechanical properties of the composites pultruded using the modified technique were marginally superior to those manufactured using the conventional resin bath. However, the environmental benefits of the modified pultrusion process were demonstrated to be significant.

Fibre-reinforced composites consist of three key components: the reinforcing fibres, the matrix and the interface between the fibre and the matrix. The efficient impregnation of the reinforcing fibre bundle by the matrix is a primary prerequisite for the production of advanced fibre-reinforced composites. This process can be significantly enhanced by spreading the filaments in the reinforcing fibre bundle. The authors previously reported on a manual technique for spreading the filaments in a bundle. This involved subjecting a fibre bundle to a series of reciprocating motions over a rod. The effect of releasing the tension on the bundle was also considered. On the basis of the observations made in the previous study, a mechanised rig was designed, manufactured and optimised to enable the lateral spreading of the filaments in a bundle of E-glass fibres. A Taguchi-based approach was used to optimise the variables on the rig such as the number and configuration of rollers, haul-off speed of the fibre bundle, pre-tension in the bundle and the rotational speed of the roller carrier hub. The maximum degree of fibre spreading achieved for a commercially available 2400 tex E-glass fibre bundle was 250%.

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