Numerical Modeling of Processing Parameters for Slot and Discrete Port Tapered Configurations in Resin Injection Pultrusion

Abstract

Pultrusion is a very cost effective method for manufacturing structural components of constant cross-sections for aerospace applications. The quality and mechanical strength of the pultruded part depends on the wetout of the fiber reinforcement by the liquid resin; the strength and thus the quality of the composite are superior when the fiber reinforcement is fully impregnated (complete wetout) with liquid resin. This work explores the wetout characteristics in the injection pultrusion process. Complete wetout of the dry fiber matrix with liquid resin depends significantly on the processing parameters. The process parameters, fiber pull speed, fiber volume fraction, and resin viscosity are explored in this study. The finite volume technique is employed to simulate the flow of polyester resin through the fiber matrix (glass rovings) and the impact of the process parameters on the injection pressure required to achieve complete fiber wetout is investigated. The location of the liquid resin flow front is predicted for the discrete port injection and the slot injection configurations. Results show the impact of the tapering of the injection chamber walls on the minimum injection pressure required to achieve complete fiber wetout and the corresponding resin pressure at the injection chamber exit. A small taper on the walls of the injection chamber was found to have a significant impact on the minimum injection pressure necessary to achieve complete fiber matrix wetout.