Characterization of shear behavior of warp-knitted fabrics applied to composite reinforcement

Abstract

Different types of textile fabrics are now widely used for reinforcing composite structural parts. In this work, three types of weft-inserted warp-knitted fabrics differing in stitch pattern and composed of glass roving were produced. The shear behavior of the developed fabrics was determined according to stitch type. Three basic stitch types were chosen: tricot, cord, and pillar. The shear behavior was examined by the picture frame test method. It was observed that the stitch type significantly affects the shear behavior of the fabrics. The deformation phases during the fabric shear test were analyzed. To estimate the changes in the shear stiffness of the fabrics, shear moduli were calculated as a function of the shear angle. In general, the fabric with the tricot stitch has the greatest shear resistance than that of fabrics with the cord and pillar stitches. The results of the characterization of shear behavior of the warp-knitted fabrics are presented and discussed.