Resin Flow, Cure and Heat Transfer Analysis for Pultrusion Process

Abstract

This work presents temperature and degree of cure profiles within a pultruded composite and focuses on the development of different models used for predicting the velocity profile including a slip velocity model. This study uses a variable viscosity model and highlights the results for the velocity profile, viscosity of resin within a pultrusion die, gelation lengths, iso-gelation lines, and axial pressure profile. Gelation was predicted to occur at about one-third the distance down the die length and the degree of cure at gelation was computed to be about 0.34. The composite systems considered in this study are graphite/epoxy and fiberglass/epoxy. A comprehensive two-dimensional mathematical model in cylindrical coordinates was developed for resin flow, cure and heat transfer associated with the pultrusion process. A control-volume-based finite difference method (Patankar method) was used for solving the governing equations. The model can be utilized for ascertaining the effects of pultrusion process variables on the characteristics of the cured composite; this primarily reduces to a large extent the trial and error experimentation often required. Moreover, insight for characterization and optimization of the pultrusion process is a direct result of this modeling.