Strength of a Cotton Yarn with Particular Reference to the Structure at the Region of Break

Abstract

The strength of a cotton yarn has been examined critically with reference to the twist, diameter, and number of fibers at the place of break. Two cottons showed that a majority of specimens broke at a place where the diameter was minimum and twist maximum. The results were also used to examine the relationship between diameter, turns per inch, and twist angle. Counts of the number of fibers at various points in the broken specimen under the microscope made possible an estimation of the number of broken fibers and the percentage of fiber strength used in yarn rupture and these were compared with the theoretical predictions made from Kohler's formula. The percentage of fibers broken and the percentage of fiber strength utilized in yarn strength were much higher than those recorded by previous workers, the reason for this being that the present values were based on the actual number of fibers present in the cross section at the place of break. The results were also examined in the light of Shorter's theory by relating the strength deficiency fraction with the twist angle at the place of break. In addition, some data on the length of slippage, apparent density, and their relationships are given.