Mechanical behavior of hybrid biaxial single jersey knitted-reinforced composites: Experimental and numerical approaches

The biaxial weft-knitted (BWK) preform is a unique category of weft-knitted preforms that combines the ad-vantages of non-crimp and knitted architectures. Non-crimp yarns provide in-plane mechanical properties, whereas knitted yarns provide damage tolerance, toughness, and formability. They are typically produced on flat knitting machines using interlock or rib gating and the loop transfer technique. This study used experimental and numerical approaches to explore the tensile properties of biaxial single jersey knitted (BSJK)-reinforced com-posites. BSJK fabric was produced on a computer-controlled flat knitting machine using nylon 6.6 and jute yarns as knitting and straight yarns, respectively. For preparation of the composite samples, polyester resin was injected into the produced knitted fabric by vacuum-assisted resin transfer molding. Tensile tests were conducted on composite samples in the course and wale directions. After the experimental tests, geometric equations were developed for the BSJK fabric. Then, a meso-scale finite element model was proposed using the developed geometric model in the ABAQUS environment. A user-defined material subroutine was prepared to predict the tensile stiffness, as well as the strength. The findings revealed that the produced BSJK-reinforced composite can be tailored to have excellent in-plane tensile characteristics; moreover, the developed geometric equations can adequately predict tensile behavior.

Automated summary

This study explored the tensile properties of biaxial single jersey knitted (BSJK)-reinforced composites using experimental and numerical approaches. The composite samples were prepared by injecting polyester resin into the produced knitted fabric, and then subjected to tensile tests in the course and wale directions. The findings revealed that the produced BSJK-reinforced composite exhibited excellent in-plane tensile characteristics, and the developed geometric equations adequately predicted the tensile behavior.