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° to 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.

Experimental investigation of vegetal and synthetic fabrics cohesion in order to prevent the tow sliding defect via frictional and pull-out test

“…For carbon fiber tows, the results obtained in Fig. 6 are in line with the literature [42] for similar tows and conditions. As the shear angle increases, the friction coefficient increases as well with a noticeable difference being at 45°(5% increase to initial 0°angle).…”

“…The wear on the other hand decreased the amount of sizing on the tows and as such, the friction coefficient. Then, in another paper, Tourlonias et al [42] investigated the effect of the angle between fibers or tows on the fiber-tofiber and tow-to-tow friction coefficient. they found out that the friction coefficient evolves little except for angles very close to zero, reaching the highest friction coefficient for both configurations.…”

Transversal friction of epoxy-lubricated and dry carbon tows: From initial stages to stabilised state

“…Similar models of adhesive contact with ideal packing of fibres in a tow were used to explain the experimentally observed dependency of friction on the angle between two carbon tows [9,12,13]. The measured friction coefficient was significantly higher in a parallel arrangement than a perpendicular one, with a very rapid decrease between 0° and 10°, and almost no further change up to 90°.…”

“…Compared to the individual fibres, the friction of a carbon fibre tow is easier to measure but more difficult to explain and to model. However, there is growing interest in such measurements, as highlighted by recent publications on this topic [5][6][7][8][9][10][11][12][13]. The friction between a carbon tow and a tool was measured by Cornelissen et al [6], using a tow in a contact with a smooth and a rough cylinder, and later by Mulvihill et al, with a smooth [9] and a rough [10] plane; in the latter set of experiments, it was found that the coefficient of friction of a carbon tow was twice as high against a smooth metallic counterface (with an arithmetical mean deviation of the roughness height, Rq = 0.02 µm) than the rough one (Rq = 1.1 µm).…”

Modeling of fibrous tow transmission considering residual strain and friction

“…The tensile force T 1 of the fiber at different positions can be obtained by applying the Roder method, as follows 30,53…”