||Continuous measurement of apparent Poisson's ratio for yarn based on omni-directional diameters
Takatera, Masayuki ,
Arichi, Tamotsu ,
Peiffer, Julie ,
Zhu, ChunhongKim, KyoungOk
746 , 2017-04-01 , SAGE PUBLICATIONS LTD
We proposed a new method for measuring apparent Poisson's ratio for yarn and developed a new tensile tester equipped with a digital micrometer that can measure the omni-directional diameter of the yarn annularly while the yarn is elongated. Values of apparent Poisson's ratio were obtained from the longitudinal and transverse strains continuously. The mean diameter measured omni-directionally was used to calculate the transverse strain for each longitudinal strain. We tested five spun yarns, one monofilament yarn and two filament yarns and obtained values of apparent Poisson's ratio against longitudinal strain for all samples. Apparent Poisson's ratio was not constant for spun and filament yarns, while it was constant for monofilament yarn. When the longitudinal strain was low, apparent Poisson's ratios of ring spun yarns and filament yarns were large, owing to the fiber packing density. As the longitudinal strain increased, apparent Poisson's ratio gradually decreased. Furthermore, we approximated the relationship between apparent Poisson's ratio and the longitudinal strain using a power function. The apparent Poisson values can be used in the simulation of fabrics.