Mechanical characteristics of bionic pseudostem-like multilayer weft-knitted spacer fabric for personal protection

Inspired by the multi-layered structure found in banana pseudostem, an innovative bionic pseudostem-like multilayer weft-knitted spacer fabric (ML-WKSF) was proposed for the development of high-performance and mass-produced personal protective materials. ML-WKSFs with different spacer filament diameters (0.15, 0.175, and 0.2 mm) were produced on a computerized flat knitting machine, incorporating thermoplastic filaments during the knitting process to enhance structural supporting of the spacer filaments. In both flat compression and fatigue compression tests, the ML-WKSF with 0.15 mm filament exhibited superior compressive resistance and fatigue resistance due to the more compact fabric structure resulting from the smaller diameter monofilaments, which facilitated uniform stress distribution. Additionally, composite fabrics were prepared using a shear thickening fluid (STF) with a SiO 2 mass fraction of 70%, and mechanical property tests were conducted. The composite fabrics displayed similar trends to the pure fabrics in both flat compression and fatigue compression tests. Differently, the integration of STF with the monofilaments led to an increase in compressive load bearing capacity. In low-velocity impact tests, larger spacer filaments resulted in better impact resistance for the fabrics as the impact force was locally dispersed. The composite with 0.2 mm spacer filaments demonstrated excellent impact resistance and energy absorption, achieving an energy absorption efficiency of 69% at an initial impact energy of 40 J.