Effects of Geometry of Ring Spinning Triangle on Yarn Torque: Part II: Distribution of Fiber Tension within a Yarn and Its Effects on Yarn Residual Torque

This paper presents a theoretical analysis of fiber tension distribution within a ring spun yarn without relaxation. Yarn residual torque is determined on the basis of the translation of fiber tension at the spinning triangle, as presented in the first part of this series of papers, into the fiber tension within the yarn. The results from numerical simulations indicate that, with fiber buckling, the yarn exhibits a lower average fiber tension and, thus, a much reduced yarn residual torque than that without fiber buckling. Comparison with experiments confirmed that fiber buckling exists in ring yarns while the assumption of no fiber buckling is not realistic. Generally, a low yarn twist results in low average fiber tension in the yarn and, thus, a reduced yarn residual torque. A symmetrical spinning triangle leads to a slightly higher yarn residual torque than a right-angle spinning triangle when the yarn counts and twists are identical and fiber buckling occurs.