Research on fiber tension at asymmetric spinning triangle using the finite-element method

Abstract

Spinning triangle is a critical zone in the ring spinning process of staple yarn, whose geometry influences the fiber tension distribution in the spinning triangle directly and determines the spun yarn qualities. In ring spinning, the spinning triangle is often asymmetric due to the inclination angle of the spinning tension or the migration of the axis fiber at the front roller nip. Therefore, in this paper, the fiber tension distributions in the asymmetric spinning triangle due to the migration of the axis fiber at the front roller nip were studied using the finite element method (FEM). In the direct finite-element model, the initial strain of the axis fiber is set as zero, and the accidental fiber tensions would be produced due to the asymmetric distributions of the initial strain on fibers in the two sides of the spinning triangle. Then, an effective finite-element model of the asymmetric spinning triangle with right (left) axis fiber migration for calculating the fiber tension is built by composing an asymmetric spinning triangle with a corresponding left (right) axis fiber migration and a symmetric spinning triangle is composed. Then, the fiber tension distributions in the spinning triangles in the Ne40 (14.6 tex) and Ne60 (9.7 tex) cotton spun yarn were numerically simulated with different axis fiber migrations and twist factors. Furthermore, the accuracy of the proposed finite-element model in calculating the fiber tension distribution in the asymmetric spinning triangle was validated by comparing it with the theoretical model built by the energy approach. It is shown that the numerical values of fiber tension distribution between the FEM results and the results with the energy method are in good agreement. Meanwhile, with the increase in the migrations of the axis fiber or the yarn twist, fiber tension in the spinning triangle is increased.