Theoretical study of spinning triangle with raised part

Spinning triangle is a critical region in the spinning process of staple yarn, the geometric and mechanical performances of which plays an important role in determining the physical performance of spun yarns. Taking appropriate measures to influence the spinning triangle geometry and improve the qualities of yarn has greatly attracted interest of many researchers recently. In these modified ring spinning systems, the raised parts at spinning triangle are often existed, i.e. the fibers in the spinning triangle are not on the same plane, but a part of fibers is squeezed into the middle part of spinning triangle by the heavy twist. Therefore, in this paper, a new theoretical model of fiber tension distribution in the spinning triangle is proposed by considering the raised parts at spinning triangle based on the principle of minimum potential energy. The relationships between the fiber tension and the spinning triangle shapes are presented. Then, a theoretical model of the residual torque within a yarn due to the fiber tension was given correspondingly. Finally, as an application of the proposed method, Ne32 cotton yarns were taken as an example for the simulation. The fiber tension distributions in the spinning triangle and corresponding residual torque within a yarn were numerically simulated and the results were compared with those by earlier models, in which the fibers in the spinning triangle were assumed to be located on the same plane.