Effect of inter-tow angle and temperature on the static coefficient of friction of preimpregnated tows in tow-tow and tow-metal contact

Abstract

The objective of this study is to quantify the frictional properties of tow materials utilized in filament winding processes for the manufacturing of carbon fiber reinforced plastic (CFRP). The study aimed to investigate the influence of inter-tow angle (ITA) and temperature on the static coefficient of friction (sCoF) of commercially available towpregs. A series of experiments was conducted to measure the frictional behavior of the towpregs under varying ITA's (0°–90°) and temperatures (22 °C–60 °C). The results demonstrate a clear correlation between ITA and friction. Lower angles (0°–10°) exhibit higher friction due to mechanical entanglement and embedding. At higher angles (20°–90°), the static coefficient of friction decreases, reaching a minimum at 90°. Furthermore, temperature has been identified as a crucial factor in reducing friction. Compared to 22 °C, at 30 °C, a 35 % decrease in the static coefficient of friction was observed, while at 50 °C, a 54 % reduction was noted. Beyond this point, the friction levels appear to stabilize, suggesting that the resin viscosity and friction properties reach a plateau. A supportive rheological analysis of the resin system revealed a notable decline in viscosity with elevated temperatures, which further substantiates the observed reduction in friction. These findings highlight the combined influence of tow alignment and thermal conditions on the sCoF, with significant implications for the design and processing of composite materials in filament winding. The results indicate that meticulous consideration of ITA and temperature is essential for optimizing composite material performance, particularly in filament winding applications.