Frictional behavior of carbon fiber tows: a contact mechanics model of tow-tow friction

Composite-forming processes involve mechanical interactions at the ply, tow, and filament level. The deformations that occur during forming processes are governed by friction between the contacting tows on the mesoscopic level and consequently between filaments on the microscopic level. A thorough understanding of the frictional properties at the level of individual filaments is essential to understand and to predict the macroscopic deformations of a textile reinforcement during forming. This work presents a contact mechanics modeling approach to provide a theoretical background of the frictional behavior of dry fibrous tows in contact with each other. The predicted frictional behavior is in qualitative and quantitative agreement with experimentally observed frictional forces of carbon fiber tows in sliding contact. The relative orientation of the contacting tows is of great importance for the developed frictional forces in the contact.