Abstract
Strain recovery behaviour after static elongation was investigated on crimped synthetic yarns, when constant rate elongation was applied to the yarn.
Residual strain decreases gradualy after elongation is reversed. Irreversible strain depends on the rate of elongation and on the applied elongation. Highest recovery was observed for the yarn on the applied elongation, prepared by the stuffer-box method, and the lowest for the one prepared by the conventional-twist method when ts, recovery time, is small. However, the differences of the recovery behaviour among yarns prepared by different methods become small when ts is large. The relation between after-effect- stress and residual strain is approximately linear in each yarn. The gradient of the liner relation is reciprocals of elasticity of relaxation element.
