Abstract:

This work deals with the role that twist directions at the contact point of warp and weft play in the mechanical behaviour of fabrics. Two sets of 100 percent combed cotton yarns (20 tex) of different twist directions (Z & S) and six twist levels were produced and then used as wefts on an old type Dornier loom (weft insertion of 120 picks/min), in which the warp was 100% combed cotton yarns with 870 Z twist per meter. Hereby we obtained two sets of fabrics in which the warps were all the same but the wefts were different in the twist directions and twist levels. Then the fabrics were compared with respect to the yarn pullout (two adjacent yarns were pulled out at the same time), the fabric formability (product of bending rigidity and reverse value of initial modulus) and fabric buckling (200-g tensile concentrated force was applied to the fabrics). The results show that the yarn pull-out force, fabric formability and fabric buckling force were greater in the fabrics in which the warp and wefts were unidirectional in the twist directions. In addition, in the group in which the warp and weft twist directions were the same, the maximum pull-out force, maximum formability and maximum buckling force belonged to the fabrics in which the nesting angle was around zero.