Prediction of Capillary Pressure for Resin Flow within Fiber Unit Cells

Abstract

The flow of resin into fiber tows is driven by the applied pressure gradient and the capillary pressure, which is dependent on the static contact angle between the fibers and resin as well as fiber diameter and arrangement. Commonly, only two fibers are used to calculate the average capillary pressure, which does not take into account the effect of neighboring fibers in a closely packed tow. This paper introduces a novel method to calculate the average capillary pressure of resin moving through a unit cell containing five fibers. Both numerical and analytical solutions are presented, validated, and compared. The role of selected parameters on average capillary pressure is investigated. This work should prove useful in predicting the average capillary pressure of resin moving between fibers and the results can be used to address filling of fiber tows.