A mechanical analysis of yarn twist distribution in frictional contact zone

This paper presents a mechanical model in which dynamic equilibriums of forces and moments are considered. This model is capable to described, quantitatively, distributions of four function in the frictional contact zone, which are deviate angle, yarn tension, frictional force and yarn twist. It can be used to characterize twist blockage between the yarn and guide in terms of yarn, machine, and operational parameters (such as twist, yarn torque, yarn torsional rigidity, yarn tension, yarn count and the wrap angle of yarn over the yarn guide). The effects of these factors are discussed for the case that the yarn twist is independent of time and the yarn speed is much lower than that of strain wave propagation.