Modelling the impact of tensile and shear forces during the loop-forming process in knitting

Knitting is a dynamic process during which the yarn simultaneously receives several mechanical forces such as tensile, shear and bending, especially when the new loop is drawn out of the old one by the needle hook. Many researchers analysed the factors mainly focusing on the tension variation during loop formation but seldom studied the impact of shearing force during new loop formation in detail. This paper presents an innovative method that introduces the shearing force as an important factor in the theoretical calculation model of forces in an integrated manner to understand the effect of tensile and shearing forces during a new loop-forming stage. It proves that the impact of shearing force acting along the yarn’s cross-section is much more severe, which needs to be considered in the knitting machine design, knitting yarn selection and knitted products’ quality control.