On-Line Processing of Unidirectional Fiber Composites Using Radiative Heating: I. Model

Abstract

Thermal radiation is a clean, flexible, efficient and effective means to supply energy to process a composite on-line. Radiative transfer in high-fiberdensity, unidirectional composites is complex, if analyzed completely. A detailed thermal model for on-line processing of unidirectional fiber composites by surface or volumetric radiative heating is presented. The physical geometry and imposed thermal and radiative boundary conditions correspond to a unidirectional, hoop-wound cylinder. In-situ (or continuous) curing of thermosets or on-line consolidation of thermoplastics is represented by the inclusion or omission, respectively, of the exothermic, chemical energy release term in the energy equation. Numerical results are presented for the temperature and degree of cure of graphite/epoxy and glass/epoxy cylinders. The effects of: surface or volumetric radiative heat flux; radiant-source emissive power level and efficiency; radiative emission from the composite; exothermic, chemical energy release; radiation’s angle of incidence; and independent and dependent scattering in the composite’s interior are presented. Validation of the model is presented in Part II of this paper, as well as recommended manufacturing process windows for process parameters, such as radiant-source emissive power level and winding speed. Part II also includes surface and volumetric radiative properties of unidirectional graphite/epoxy and glass/epoxy composites that were used in the numerical simulations.