Transverse permeability of direct glass rovings

Rovings are used in a variety of polymer processes such as filament winding and compression molding. In all these processes, impregnation of the roving monofilament bundle by the liquid polymer is essential. Modeling polymer impregnation requires an estimate of the transverse Darcy's Law permeability. This study measured the transverse permeability of 2400 tex glass rovings as a function of applied compressive stress, monofilament diameter, roving thickness,;fluid velocity and viscosity. The permeability was observed to depend strongly on the compressive stress, and hence void fraction. The permeability was independent of the monofilament diameter, roving thickness, fluid velocity and viscosity. Results are presented using a simple model that accounts for roving void fraction inhomogeneities.