Interply friction of carbon fiber/epoxy prepreg stacks under different processing conditions

The interply friction of prepreg is commonly found from the pre-forming to the final curing process during the fabrication of composite materials. In this study, a testing device was established to evaluate the slipping behavior of two kinds of carbon fiber/epoxy prepreg systems and the dominated friction mechanisms under different processing parameters, including temperature, pressure, and pulling rate, are determined. The interply frictional resistances of prepreg stacks were studied with the surface morphology observation and the surface roughness measurements. The results indicate that the friction mechanism of the two prepreg systems is the mixed friction, which could change from the Coulomb-dominated friction to the hydrodynamic-dominated friction under different processing conditions. The surface morphology and surface roughness of prepreg have significant effects on the slipping behavior controlled by the mixed friction. The Coulomb-dominated friction is not conducive to the slippage of prepreg and may result in fiber wrinkles in the laminates. The hydrodynamic-dominated friction should be achieved by adjusting the processing conditions to avoid manufacturing defects.