Experimental Investigation of Slip and Strength Characteristics of Hybrid Yarns
Final rept. 1 Aug 2002-31 Jan 2003
NORTHEASTERN UNIV BOSTON MA DEPT OF MECHANICAL ENGINEERING
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The general goal of this project is to contribute to the development of advanced hybrid yarns for woven fabric body armor and general dynamic applications. Blending stiff low elongation-to-break LE fibers with compliant high elongation-to-brake HE fibers improves the overall strength of a blended yarn. Interfacial slip between fibers is thought to play an important role in this process. The specific objective of this work is to perform experiments on fiber-to-fiber interfacial slip behavior in fibrous assemblies. Various hybrid yarns were simulated experimentally by helically wrapping HE fibers over a LE core fiber at different helix angles. The strength characteristics of these blended yarns were tested in tension. In particular a novel experimental procedure is developed to measure the slip of the core fiber after the first brake occurs. The tests are carried out to show the existence of multiple breaks. The strength of the hybrid yarns is compared with the strength of a single yarn.