Effects of gage length, loading rates, and damage on the strength of PPTA fibers

Abstract: Axial tension and transverse compression experiments on single fibers were performed to investigate the mechanical behavior of three high-performance fibers (Kevlar®, Kevlar® 129, and Twaron®) with diameters in the order of 9–12 μm. The single fibers were manufactured from 1998 through 2008. A miniaturized tensile Kolsky bar was used to determine the tensile response of PPTA single fibers at a high strain rate. Gage length and strain rate were found to have minimum effects on the tensile strength of PPTA single fibers. Manufacturing time over a decade was found to have negligible effects on the tensile strength of the fibers. Initial transverse compression on the fibers reduces their ultimate tensile strengths. A high resolution scanning electron microscope (SEM) was also used to examine the fracture modes of transversely deformed fibers. Different types of fracture morphology were observed. [Copyright &y& Elsevier]