Analytical prediction of resin impregnation behavior during processing of unidirectional fiber reinforced thermoplastic composites considering pressure fluctuation

In order to fabricate composite components more rapidly, a micro-braiding technique has been proposed as fabrication of intermediate material for continuous fiber reinforced thermoplastic composites. In the present study, a simple model considering pressure fluctuation during compression molding is proposed based on the Darcy's law and the continuity equation to predict resin impregnation process using micro-braided yarns. In order to measure pressure fluctuation, a mold die including a channel from the cavity to a pressure gauge was fabricated. To confirm validity of the model, carbon fiber reinforced polypropylene composites were molded under various molding conditions. Once molding pressure was applied, pressure on the molding pieces rapidly increased and gradually decreased to equilibrium with time. Analytical results well-predict resin impregnation during molding and the effectiveness of the model proposed was confirmed.