摘要: A variant of the auxetic helical yarn is explored herein by means sewing an inextensible thin cord through elastic fat cord, in a triangular pattern, to form semi-auxetic yarn. When stretched longitudinal direction, exhibits conventional and behavior plane perpendicular parallel, respectively, which lies on. simplified model developed describe effective Poisson's ratio planes terms initial half angle cord. Results show that decreases increases with while both parameters. In addition, dominant parameters for are respectively. Finally, other types yarns same category proposed suggested ways producing them.