Testing And Researching On Weft-Knitted Fabric Under Biaxial Tensile

The tensile fracture mode of the knitted-fabric was complicated during the actual application. It contained simultaneous tensile modes in different directions. And the tensile rate and tensile strength were also different. The tensile deformation has changed great. For the application limit of the instrument, there was rare research in the biaxial tensile of weft-knitted fabric in china. The domestic tensile testing usually tested under uniaxial tensile mode. The foreign research was based on the geometric mode of the weft plain knitted fabric or rib knitted fabric in the initial states. And the tensile testing mode was single. This paper was to research the biaxial tensile properties of different weft-knitted fabric under various experimental conditions. The law of the biaxial tensile properties with the weft-knitted fabric was discussed under different tensile conditions and with different fabric structures. It provided basics for the comprehensive assessment of the difficult degree of the fabric that fractured under extremely complicated conditions.First, the rib-knitted fabrics with different stitch density have been designed and knitted. The fabrics were pre-treated by alkaline-oxygen-cooking-bleaching one-bath processing to make them suitable for the usual application.Second, the mechanical properties of weft-knitted fabric under biaxial tensile have been researched. The breaking strength, breaking extension, stretch modulus and work of rupture of rib-knitted fabric with 7 directions were tested on a domestic X-Y electronic strength tester. Some factors influencing the mechanical properties were analyzed. And it's found that there were the relations of trigonometric function between tensile properties and loading directions.Third, the mechanical properties of weft-knitted fabric under different extension rate have been researched. The tensile fracture mode involves fixed one edge then moved the opposite clamps that gripping the fabric or moved all the 4 clamps that gripping the 4 edges of the fabric. When moved all the clamps, the extension rate of the opposite clamps could be the same or the different. The trends of the extension rate influenced mechanical properties of weft-knitted fabric under biaxial tensile have been attained.And then, the behavior of the weft-knitted with different fabric construction and stitch density under biaxial tensile have been studied. The relative breaking strength, breaking extension, stretch modulus and specific work of rupture of tested weft-knitted fabric have been tested, calculated and analysed. The trends of the fabric construction and stitch density that influenced the mechanical properties of weft-knitted fabric under biaxial tensile have been attained.At last, the processing and mechanism of the weft-knitted fabric under biaxial tensile have been analysed. And the limitations during the testing have also been indicated...