The Effect of Rib Fabric Pattern and Yarn Composition on the Mechanical Properties of Polyester Matrix Composites Reinforced by Weft-Knitted Fabric

Abstract

In this study, polyester matrix composites reinforced by 1x1, 2x2, half- and full-cardigan rib pattern weft-knitted fabrics from glass and glass/aramid hybrid yarns were produced. Physical properties such as thickness and volumetric density were determined. Tensile, flexural and low velocity impact tests were applied to the composite samples. The 2x2 rib pattern composite showed the highest thickness and density. The hybridization of glass yarn with aramid yarn increased the thickness, while it decreased the density of composites. The 2x2 rib pattern composite showed the highest tensile modulus and tensile strength. Yarn hybridization increased tensile strength at statistically significant level. The composite with full-cardigan rib pattern displayed considerably higher flexural modulus and flexural strength than the composites with the other patterns. When glass and hybrid composites were considered separately, the rib fabric pattern exhibited significant effect on maximum load. The rib fabric pattern displayed also significant effect on absorbed energy for glass composites. The yarn hybridization dramatically increased maximum load and absorbed impact energy. Rib fabric pattern and yarn composition variables displayed the parallel effect on bursting strength of the soft knitted fabrics and maxium impact load of the composites.