Development of a Numerical Model to Predict In-Plane Heat Generation Patterns During Induction Processing of Carbon Fiber-Reinforced Prepreg Stacks

A numerical model is proposed to describe in-plane heat generation spatial response during induction processing of carbon fiber-reinforced thermoplastics. The model is based on a unified approach that considers three possible heating mechanisms: fiber heating (Joule losses in fiber), noncontact junction heating (dielectric hysteresis), and contact junction heating (Joule losses at junctions). A lumped meshing scheme is used to construct a numerical representation for cross-ply and angle-ply orientations of 2-ply prepreg stacks. Heat generation patterns are calculated based on voltage and current conservation laws and verified with induction heating of AS4 carbon fiber-reinforced polyetherimide (AS4/PEI) prepreg stacks. Excellent agreement is found except at very low angle-ply orientations where the predicted heating patterns show significant deviations from the experiment results. A sensitivity analysis is also performed to assess the relationship between heating patterns and material and process parameters. The results show that the stack angle between plies and intrinsic prepreg microstructure can significantly affect the heating patterns.