Experimental and theoretical study on the strain rate dependence of the mechanical properties of Twaron fiber tows with different fiber fineness

Abstract

In this study, the tensile impact property of Twaron fiber tows with different fiber fineness were characterized and compared. A self-designed split Hopkinson tension bar apparatus and MTS materials tester (MTS 810.23) were used to determine the tension behavior of Twaron fiber tows under different strain rates (quasi-static: 0.001 s^–1, dynamic: 800–2400 s^–1). The results showed that the mechanical properties of the Twaron fiber tows were sensitive to strain rate; the stiffness and failure stress of the fiber tows increased distinctly as the strain rate increased, whereas the failure strain decreased. The scanning electron microscope photographs showed that a fibrillated end of a Twaron single fiber failed at both quasi-static and high strain rates. The observations reaffirmed that the fiber fibrillation was more severe as the strain rate increases. In addition, the fiber of 220 dtex exhibited higher strength and stiffness than that of 1680 dtex. Combined with the aligned fiber bundle model and the statistical theory, a single Weibull distribution function is adapted to evaluate the strength distribution, and the Weibull plot for Twaron fiber tows under different strain rates provided a more accurate agreement with the experimental results.