Response of yarn systems to impact loading

Abstract

Fabrics constructed from high-strength polymeric fibres are widely used in flexible body armour and hard-armour composite plates. This investigation is directed at improving the methodology for high strain rate testing of high-strength polymeric fibres based on the tensile split Hopkinson bar method and the transverse impact method, to obtain the dynamic mechanical response of Spectra 900 yarn and Spectra Shield flexible laminated composite. The responses obtained enable the establishment of accurate rate-dependent, viscoelastic constitutive models for these materials. Finite element analysis is used to assess the accuracy of the experimental methods. A related objective is to formulate a computational model for Spectra 903 woven fabric that incorporates the material model derived for Spectra 900 yarn, together with realistic geometrical details of the woven fabric structure and inter-yarn interactions. This fabric model is employed in a parametric study of the influence of projectile velocity on the ballistic response of the fabric. Projectile penetration tests are carried out to validate the computational results.