Influence of friction angle between carbon single fibres and tows: Experimental analysis and analytical model

Abstract

Friction between single fibres or between tows is an important element in the mechanical properties of composite reinforcement. Therefore, knowledge of the friction behaviour at the two scales, tow and fibre, is necessary for a deep understanding of the mechanical behaviour of composite reinforcement. In the models, the strategy used is to consider a constant coefficient of friction. This paper presents an efficient method of measuring the coefficient of friction relative to an inter-tow or inter-fibre sliding angle of 0–90°. The results show that the coefficient of friction decreases when the angle increases. Moreover, the friction is very high when the fibres are parallel. This result is explained by the increase of the adhesion between fibres at the interface of the tows due to a large total contact area at 0°, as proved by an analysis performed based on Hertz’s contact theory.