Abstract:

Negative Poissin's ratio (NPR) materials have excellent and unique mechanical properties. Knitting structure is one of the best structures to make the NPR materials.  In this paper, the structures and mechanical properties of NPR fabrics produced in knitting machines were studied. First of all, the structure of NPR fabric was design, their weaving processes were determined, and knitting is performed on a KS4 Tricot knitting machine.Then, the tensile properties testing of fabrics were performed in the directions of 0 °, 45 °, 90 ° and 135 °, and by stretching a stress-strain curve in different directions and a Poisson's ratio-strain curve, the mechanical properties of the fabrics were studied, and the final destruction morphologies of several fabric stretched in different directions were analyzed, and the results show that differencesin mechanical properties exist between different tabrics and in directions.

Key words: negative Poisson's ratio effect, warp knitted fabric, stretching, mechanical properties