Influence of viscosity, binder activation, and loading rate on the membrane response of an infiltrated UD-NCF

Abstract. Shear-tension coupling of engineering fabric is one of the most important behaviors during the draping phase of liquid composite molding (LCM) processes, including wet compression molding (WCM), which occurs with the infiltrated fabric and, in some cases, with the use of a stabilizing binder. In the present study, the membrane behavior of an impregnated and binder-stabilized uni-directional carbon fiber non-crimp fabric was characterized by performing off-axis tension tests. These tests allow the investigation of the influence of stabilizing binder, fluid viscosity and loading rate on the fabric membrane behavior. As result of these experimental tests, an increase in membrane force is noticed when the stabilizing binder is activated, attributed to a greater shear stiffness. Additionally, a decrease in forces is observed for impregnated fabric compared to dry textiles caused by a lubrication layer between fiber tows. The study provides a better understanding of the membrane behavior of the impregnated and binder-stabilized UD-NCF, which is relevant for a potential high-volume production process.