Friction between yarns is a crucial phenomenon in fabric manufacturing processes, and it becomes more complex when using lubrication agents to improve processing. This work presents an experimental investigation of the frictional behaviour of different combinations of yarns under dry and wet conditions, as occurring in overbraiding processes. The experiments were designed to maintain a constant yarn tension, and subsequently also a constant normal force and contact area during the test. Both the inter-yarn angle and the normal force significantly influence the friction coefficient. The additional contribution of the capillary force results in consistently higher friction coefficients for the water-lubricated yarns compared to the dry yarns. An anisotropic friction model is proposed to capture the influence of the inter-yarn angle, normal force, and capillary effects observed during the experiments. The model shows that the friction follows Amontons’ friction at high external normal forces and Howell’s friction at moderate normal forces.

中文翻译：

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纱线间摩擦的细观模型

纱线之间的摩擦是织物制造过程中的一个关键现象，当使用润滑剂来改善加工时，摩擦会变得更加复杂。这项工作对不同纱线组合在干和湿条件下（如过度编织过程中发生的情况）的摩擦行为进行了实验研究。实验旨在保持恒定的纱线张力，并随后在测试过程中保持恒定的法向力和接触面积。纱线间角度和法向力都会显着影响摩擦系数。与干纱线相比，毛细管力的额外贡献导致水润滑纱线始终具有更高的摩擦系数。提出了各向异性摩擦模型来捕捉实验过程中观察到的纱线间角度、法向力和毛细管效应的影响。该模型表明，在高外部法向力下，摩擦遵循 Amontons 摩擦，在中等法向力下，摩擦遵循 Howell 摩擦。