Influence of Preform Braiding Process Parameters on the Nonlinear Friction Behavior of Fiber Bundles

ABSTRACT Frictional wear between fiber bundles during the braiding process is a key factor leading to the degradation of the mechanical properties of composites. To investigate the mechanism of regulating the friction behavior between yarns during the braiding process of preforms, a multi‐parameter controllable yarn friction test platform was constructed to systematically investigate the mechanisms of the influence of friction rate, normal force, preloaded tension, friction angle, and fiber type on the friction characteristics of yarns. The experimental results show that the dynamic friction coefficient between fiber bundles varies only 2.5% within the rate range of 2.5–10 mm/s, which shows excellent rate stability. The increase of normal force leads to a power‐law decrease in the friction coefficient, which is especially significant when the friction angle is smaller. This is consistent with the theory of Howell's friction model. The decrease of the friction angle leads to the approximate linear increase of the friction coefficient. The pre‐tension force is positively correlated with the contact area between fiber bundles and the friction coefficient. The study indicates the nonlinear evolution of yarn friction behavior under various influencing factors, providing important theoretical and methodological support for optimizing process parameters and achieving high‐quality, low‐damage forming of high‐performance braided precursors.