A Study of Tensile Behaviour of Ring, Rotor, Air-Jet and DREF-3 Friction Yarns at Different Gauge Lengths 1

spun and DREF-3 Friction spun yarns has been investigated at high strain rates and different gauge lengths. It is observed that the increase in gauge length from 150 mm to 500 mm decreases continually the yarn tenacity, breaking extension, but increases the breaking work and the modulus. The rotor spun yarns exhibit a minimum reduction in tenacity while the air-jet spun yarns show a greater drop in tenacity and breaking extension when tested at longer gauge lengths. Amongst all yarns, the ring spun yarns exhibit highest tenacity and modulus followed by rotor spun yarns and air-jet spun yarns. The yarn tenacity, breaking extension, breaking work and breaking time are found to be power law functions of gauge length while the modulus is preferably a logarithmic function of gauge length. The percentage increase in tenacity is higher in case of 20 Ne cotton ring spun yarn followed by the corresponding rotor spun and airjet spun yarns. All these observations ascribe to the nature of the responses of the constituent fibres at differences amongst the structures of these yarns