Failure mechanism of weft-knitted insertion fabric/Surlyn resin flexible composite for stab resistance

In this paper, two kinds of aramid fibers were used to prepare weft-knitted insertion fabrics, flexible Surlyn resin as matrix to prepare reinforced weft-knitted insertion fabrics, the effects of hot-pressing temperature, resin content, pressure and holding time on reinforced weft-knitted insertion fabric were explored. Through lamination and co-curing, the effects of the lamination numbers, preparation methods and lamination sequence on the stab resistance of the multilayer system were studied. The results showed that appropriate hot-pressing temperature, resin content, pressure and holding time can improve the stab resistance by improving the permeability of resin in the fabric. However, over high temperatures, pressure and holding time have a negative impact on the stab resistance or flexibility of the composite; high resin content means higher weight, which is not conducive to human wearing. When the area density is similar, the stab resistance of the co-cured composite is the best, followed by the superposition of single-layer composite, finally is the superposition of film and fabric. Weft-knitted insertion fabrics and reinforced weft-knitted insertion fabrics can dissipate puncture energy through shear force, tensile fracture, friction and deformation of yarn or fabric. In addition, composites also have other energy dissipation pathways such as filament compression splitting, fabric/matrix debonding and matrix delamination.