MODELING THE IMPACT OF CAPILLARY PRESSURE AND AIRENTRAPMENT ON FIBER TOW SATURATION RESIN INFUSION IN LCM

摘要

Traditionally, capillary effects have been neglected when modeling the filling stage ofrnLiquid Composite Molding processes. This simplification is justified because the inletrnresin pressures are much higher than the capillary pressure. This simplification is alsornacceptable when impregnating fabrics in which their fiber tows saturate at the same raternas the bulk preform. However, this assumption is questionable for fabrics that exhibitrndual scale in which the fiber tows saturate at a much slower rate than the bulk preform. Inrnsuch cases, the capillary pressure can influence the time to saturate a fiber towrnsignificantly and impact the overall impregnation of preform. Since the flow frontrnvelocity inside the fiber tows is significantly smaller than the flow around them, it isrnimportant to include the capillary pressure to aid the saturation of the tow. In this paper,rnwe modify our existing simulation that can predict the filling of the bulk preform and thernsaturation of the fiber tows to include the capillary forces at the fiber tow level. Importantrnparameters are identified and grouped in non-dimensional form. A parametric study isrnconducted to examine the role of these dimensionless parameters on the overall towrnsaturation levels. The modeling is extended to include the effect of entrapped air insidernthe tows on the overall saturation of the preform.