Experimental and Simulative Analysis of the Pressure Development in a Closed Injection Pultrusion Process with Multiple Chamber Geometries

Abstract

The use of innovative higher-performance highly reactive resin systems requires an enhancement of the established method of fiber impregnation (open bath) towards closed resin-injection pultrusion (CIP), due to the short pot life of the resin systems. The result is that the open bath is developed into a closed injection and impregnation chamber (“ii-chamber”). In this study, three parameters—resin viscosity, opening angle and opening factor at the injection point on the ii-chamber—are varied, each in three stages. For each set of parameters, a pultrusion trial is conducted and the process pressures in the ii-chamber and pultrusion die measured. This enables direct feedback via the process conditions of the as yet uncured composite. The data obtained are used to validate a newly developed simulation model. The model is based on Darcy’s law, which has been extended to take fiber movement into account and thus represent the resulting pressure increase in the die. The flexible ii-chamber and die concept enhance our understanding of the processes taking place in the die system. The sensitivity of the process pressures can be shown for the three influencing variables. The experiment shows that of the three influencing variables investigated, viscosity has the greatest sensitivity to pressure development. In general, it can be said that over the length of the pultrusion die system, the pressure level increases across the three measuring points.

Thermoplastic Pultrusion Process of Polypropylene/Glass Tapes

“…The conventional thermoset pultrusion die consists only of a heating/forming die [ 20 ], in which the polymerization reaction of the resin system is activated by thermal energy. In some cases, the die could present a converging entrance, but most of it has a constant cross-section [ 21 ]. The thermoplastic matrices need to be heated over the melting temperature, consolidated, and then cooled to achieve a solid composite profile.…”

Fatigue and Impact Properties of Kenaf/Glass-Reinforced Hybrid Pultruded Composites for Structural Applications

“…Calcium carbonate, CaCO3, and aluminium hydroxide, Al(OH)3, were used as fillers at 40% of the total resin weight [34]. Calcium carbonate serves as The pultrusion process parameters such as pull speed (30 cm/min), pull force (6 Bar), and die temperature (159 • C) has been set optimally according to the kenaf fibre mats' ability to withstand the force and temperature without being damaged [30,31]. The overall fibre/matrix ratio was fixed at 55/45 to achieve a high strength-to-weight ratio in the profiles [32].…”