The energy dissipative mechanisms of particle-fiber interactions in a textile composite

Abstract

Nanoindentation and nanoscratch tests made on the surface of Kevlar KM2 fibers impart contact geometries similar to a typical contact between a particle and a fiber in a particle-infused fabric. In this study, the forces required for indentation and scratching are used as a measure of a single particle gouge of the surface of a Kevlar fiber. The gouging forces and a geometric model are used to calculate the apparent friction and energy associated with particle gouging during impact. The friction associated with particle gouging can be increased up to ∼240% compared to Kevlar yarn-yarn friction levels. The energy of gouging a distribution of particles is on the order of 10% of the energy required for axial tensile failure and 25% of the energy required for transverse compression of the fiber (for a limiting transverse strain of ∼0.3). The relative contributions of the friction and energy associated with particle gouging to the overall energy dissipated by a textile composite are discussed.

Ballistic performance of Kevlar fabric impregnated with nanosilica/PEG shear thickening fluid

“…Interlocking of the fibers increases due to the additive particles intercalated between the fibers and yarns [62]. [63].…”

Recent advances in modeling and experiments of Kevlar ballistic fibrils, fibers, yarns and flexible woven textile fabrics – a review

“…The fibril diameters are in the range of 100-200 nm for Kevlar 49 121 fibers and 10-50 nm for Kevlar KM2 fibers 120 . Nanoindentation techniques are used to characterize the 3D properties of Kevlar KM2 119,122 considering the influence of fibril level heterogeneity on properties. The local compressive elastic moduli are dependent on the number of fibrils loaded by the nano-indentor.…”

“…Using similar nano-indentation techniques Cole and Strawhecker 123 reported local mechanical properties for four fibers including KM2Plus, Twaron, AuTx, and Dyneema. The nanoindentation and nanoscratch 124,125 studies are also important to understand the energy absorbing mechanisms in particle impregnated fabrics using shear thickening fluid 126 , silica nanoparticles 56,127 and carbon nanotubes (CNTs) 128 among others to improve the impact performance. These studies use probes that effectively mimic the contact in particle-fiber and reveal the effects of fundamental particle-fiber interactions on the energy dissipative mechanisms such as friction and particle gouging.…”

“…These studies use probes that effectively mimic the contact in particle-fiber and reveal the effects of fundamental particle-fiber interactions on the energy dissipative mechanisms such as friction and particle gouging. For instance, a number of fibrillar deformation mechanisms in KM2 were identified to optimize the specific energy of indentation and scratching such as transverse compression of fibrils, axial fibril tension and inter-fibril shear and friction 124 . The apparent friction (defined as the ratio of lateral scratch force to normal indentation force) is reported 120 to increase up to ~300% higher than the Kevlar yarn-yarn friction of 0.2-0.3.…”

Multi-scale computational analysis of the nano-indentation and nano-scratch testing of Kevlar® 49 single fibers

“…Examination of the public-domain literature carried out as part of the present work identified the following four recent papers which specifically deal with the nano-indentation/nano-scratch testing of Kevlar Õ fibers, all coauthored by Gillespie and co-workers. 4,[9][10][11] In 2012, McAllister et al 4 utilized AFM and instrumented nano-indentation testing to determine the local mechanical properties on the lengthscale of single fibers. The results obtained clearly established: (a) the absence of a well-defined shell section in the case of Kevlar Õ 49; (b) the presence of a well-defined, reduced-stiffness, ca.…”