During the manufacturing of particle-filled resin composite parts with a liquid composite molding (LCM) process, undesirable issues arise like resin viscosity increase or particles filtration. As the filled resin flow is taking place, the fibrous preform may act as a filter and hinder the even repartition of the fillers throughout the part or even stop the mold filling. The present paper proposes an experimental investigation of the particle filtration during the injection of a composite part. The model proposed by Erdal et al. is analysed and improved in order to take liquid retention phenomenon into account. Finally, simulated and experimental data are compared.

Molding composites constituted of fiber reinforcements, resin and fillers is of prime interest for many transportation applications. Dealing with the flow of particle-filled resin in a fibrous network raises the issue of particle retention and viscosity increase. The present study aims at simulating such molding through an efficient coupling between a filtration model, that has been previously described, and a flow model (Darcy's law). First, filling experiments are realized so as to separate cases: cake filtration, retention and no retention for two types of single-scale porous materials (polyester felt and glass fiber mat) injected with a resin filled with micro-beads. Then results of filler content, viscosity, permeability, pressure , retention profiles are simulated from the coupling between filtration and flow. Experimental data of filler profiles in the final parts, resin flow front evolution and injection times are compared with predictions obtained from the simulation.

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