Abstract
The author seeks to offer basic data on the control of yarn tension while yarn is on a machine. For that purpose, he has made experiments concerning the effects which the conditions of tensile stress have on the stress relaxation of commercial nylon and viscose yarns after the stoppage of yarn deformation. He has analyzed the results of these experiments.
Findings: (1) When a specified strain, say γo%, is applied to these yarns at a constant speed of drawing of c%/sec, the shape of the stress relaxation curve after the deformation of the yarn has ceased, becomes almost parallel to the lateral axis-which is graduated in logarithmic time-between the original point and the point which is 1 or 2 dc before the time γo/c sec. The lower the speed of drawing, the longer the range of the parallel section. The inclination of the curve becomes less steep as observation time passes. Where the degree of strain is equal, the curves of a material drawn at different speeds becomes almost parallel to one another.
(2) When the speed of drawing is varied during the process of stretch, stress relaxation is greatly affected by the speed of deformation just before the material attains the specified strain. The higher the speed, the higher the rate of relaxation.
(3) The conclusions formed in the foregoing paragraphs (1) and (2) have been deduced from the results of experiments. They agree with the results of an analysis of that relaxation process of tensile stress which is adduced from the generalized linear model.
