Effect of various knitting techniques on mechanical properties of biaxial weft-knitted thermoplastic composites

Abstract

Within the scope of experiments, five kinds of biaxial weft-knitted (BWK) fabrics with various knitting techniques (plain, interlock, tuck, tuck-miss, and interlock2) were used as reinforcement systems to fabricate thermoplastic composites with polypropylene (PP) resin yarn. Then, the final composite became BWK composites with various knitting types. The mechanical properties of composites were investigated by conducting tensile, three-point bending, and three-point bending impact tests on specimens. In all specimens, PP was commingled with glass yarn. Glass was used as reinforcement. Fiber volume fraction (V f ) of weft fibers of the interlock2 was the highest, and the length of straight part of loop shape was the longest in the interlock2 compared with the other four types of specimens. Because of the higher V f of the BWK composites with the interlock2, tensile, three-point bending, and three-point bending impact properties of the interlock2 was higher than the other four types (plain, interlock, tuck, and tuck-miss) of composite structures.

Experimental and numerical study on stiffness and damage of glass/epoxy biaxial weft-knitted reinforced composites

“…2 This is why, their applications are increasingly growing in various industries such as aerospace, transportation and construction. 3 Among the different textile structures, weft-knitted fabrics 4,5 demonstrate high deformability that makes them suitable in fabricating the complex-shaped composite parts. 6 This intrinsic flexibility is induced by the yarn interlooping which creates inferior mechanical properties in comparison to woven fabrics.…”

Investigation of the effect of CNTs on the mechanical properties of LPET/glass fiber thermoplastic composites

“…After performing the tension, in-plane shear and flexure tests, they concluded that the warp knitted material was stiffer and marginally stronger when compared to the woven material. Demircan et al 17 investigated the effect of the various knitting techniques on the mechanical properties of the biaxial weft-knitted thermoplastic composites. They found that the tensile, three-point bending, and three-point bending impact properties of the thermoplastic composites with the commingled yarns could be improved by changing the knitting techniques.…”

Analysis of Impregnation Mechanism of Weft-Knitted Commingled Yarn Composites by Staged Consolidation and Laboratory X-Ray Computed Tomography

“…By combining a commingling method of reinforcement and thermoplastic filaments with a weftknitting technology, pre-mixed dry semi-products may present a promising alternative to reduce cycle-time. In particular, biaxial weft-knitted fabrics (BWKF) are potential candidates to obtain composite parts with a complex geometry at a reduced cycle-time (Li and Bai, 2009;Risicato et al, 2014;Demircan et al, 2015). However, the better understanding of the consolidation mechanism is still required to optimize the impregnation quality of obtained products.…”