A MODELING APPROACH TO THERMOPLASTIC PULTRUSION .1. FORMULATION OF MODELS

A fundamental understanding of the effects of processing parameters an d die geometry in a pultrusion process requires a mathematical model i n order to minimize the number of necessary experiments. Previous inve stigators have suggested a variety of models for thermoset pultrusion, while comparatively little effort has been spent modeling its less we ll understood thermoplastic counterpart. Herein, models to describe te mperature and pressure distributions within a thermoplastic composite as it travels through the pultrusion line are presented. The temperatu re model considers heat transfer in an infinite slab with either presc ribed boundary temperature, or prescribed heat flux from the surfaces. The pressure model is based upon matrix flow relative to the fibers a nd incorporates a non-Newtonian matrix viscosity and a temperature-dep endent matrix density. A model to calculate the accumulated pulling re sistance from a pultrusion die, arising from viscous, compaction, and friction resistance, is also presented. The models are evaluated study ing an ideal pultrusion process for manufacturing of unidirectional ca rbon-fiber-reinforced polyether etherketone composites.