Tensile properties of ultra-high-molecular-weight polyethylene single yarns at different strain rates

This paper presents the details of experimental work on characterising the tensile properties of UHMWPE (Spectra (R) 1000) single yarns at different strain rates from 3.3 x 10(-5) to 400/s. According to the measured stress-strain curves, there was a transition from ductile to brittle behaviour as the strain rate increased from 3.3 x 10(-5) to 0.33/s; the tensile properties were highly sensitive to strain rate in this range. Specifically, the tensile strength and Young's modulus increased distinctly with increasing strain rate while the failure strain and toughness decreased. However, these tensile properties were not dependent on strain rate over the range from 0.33 to 400/s. The results showed that the measured tensile strength, failure strain and Young's modulus were independent of the tested gauge lengths (25 and 50 mm). Moreover, yarn type (warp and weft) had a noticeable effect on tensile strength, but the effect of yarn type on failure strain and Young's modulus was negligible. The microscopic examination of fractured fibres' ends revealed that fibrillation and axial splitting were the dominant fracture modes at low strain rates, while the fibres failed in a more brittle manner with little fibrillation at high strain rates.