Tensile Properties of Dyneema SK76 Single Fibers at Multiple Loading Rates Using a Direct Gripping Method

Abstract

Ultra-high-molecular-weight polyethylene (UHMWPE) fibers such as Dyneema and Spectra are seeing more use in lightweight armor applications due to higher tensile strength and lower density compared with aramid fibers such as Kevlar and Twaron. Numerical modeling is used to design more effective fiber-based composite armor. For accurate simulation of ballistic impacts, material response such as tensile stress-strain of the composite constituents must be studied under experimental conditions similar to ballistic events. UHMWPE fibers are difficult to grip using adhesive methods typically used for other fibers due to low surface energy. Based on previous studies, the ability to grip UHMWPE fibers using traditional adhesive methods depends on fiber diameter and is limited to smaller diameter fibers that could affect reported stress values. To avoid diameter restrictions and surface energy problems, a direct gripping method has been used to characterize Dyneema SK76 single fibers at strain rates of 0.001 s-1, 1 s-1, and 1000 s-1. In this report, the dependence of fiber diameter and gage length on failure strength is discussed as well as success rate of failures in the gage section with this gripping technique. A comparison of the tensile properties with previous studies is also explored.