Crimped yarn is an assembly of crimped fibers, and when the yarn is stretched, the crimp of fiber is at first stretched and then the fiber itself is to be stretched. Because the load elongation curve can be considered as made of a few regions and of course at first region the crimp of fiber is stretched.
The purpose of this paper is to determine the mechanical behavior of crimped yarn at the first region. A few results are obtained from the theoretical study and experiments.
The results are as follows:
(1) As the hysteresis loop is obtained from cyclic deformation, the mechanical hehavior of crimped yarn has a characteristic including elastic after effect and is not a perfect elastic behabior.
(2) Studying the experiments of stress relaxation, the crimped yarn may be considered as that of a linear characteristics.
(3) By the results of the above-mentioned (1) & (2), the mechanical behavior of crimped yarn may be considered to have been explained by the mechanical model including slider mechanism as shown in Fig. 2.