Hybrid Effect at Fiber Breaks in Twisted Blended Yarns

Abstract

A previously developed micromechanical model is used to formulate the problem of a blended yarn, consisting of low elongation (LE) and high elongation (HE) fibers undergoing axial extension, with a fiber break in the central region of the hybrid fiber array. A hybrid parameter R, which is the ratio of the axial stiffness of the HE fibers to that of the LE fibers, is shown to have an important effect on the intact fiber stress concentration factor (SCF), and the broken fiber slip extent at the fiber break. While the SCF increases for HE fibers adjacent to broken LE fibers, it decreases for LE fibers adjacent to broken HE fibers as R takes on values away from unity (homogeneous yarn). Higher loading can therefore be sustained by the LE fibers, and a beneficial hybrid effect can be realized.