An infiltration/cure model for manufacture of fabric composites by the resin infusion process

A one-dimensional infiltration/cure model was developed to simulate fabrication of advanced textile composites by the resin film infusion process. The simulation model relates the applied temperature and pressure processing cycles, along with the experimentally measured compaction and permeability characteristics of the fabric preforms, to the temperature distribution, the resin degree of cure and viscosity, and the infiltration flow front position as a function of time. The model also predicts the final panel thickness, fiber volume fraction, and resin mass for full saturation as a function of compaction pressure. The infiltration model is based on D’arcy’s law for flow through porous media.

Composite panels were fabricated using the RTM film infusion technique from knitted, knitted/stitched, and 2-D woven carbon preforms and Hercules 3501-6 resin. Prior to fabrication, the deflection and permeability of the preforms were measured as a function of compaction pressure. Measurements of the temperature distribution, the resin viscosity and degree of cure, and the infiltration flow front position were compared with the RTM simulation model results. The model predictions were within 12% of the experimental results.

Fabric composites were fabricated at different compaction pressures and temperature cycles to determine the effects of the processing on the properties. The composites were C-scanned and micrographed to determine the quality of each panel. Composite panels fabricated using different temperature cycles to the same state of cure and similar compaction pressures were found to have similar compressive and shear properties.

Advanced cure cycles, developed from the RTM simulation model, were utilized to reduce the total cure cycle times by a factor of 3 and the total infiltration times by a factor of 2.