Stress-Strain Relationships in Yarns Subjected to Rapid Impact Loading

Publisher Website
Google Scholar
Abstract
Samples of high-tenacity deacetylated cellulose acetate yarn were braided or plied and twisted by various amounts. Stress-strain data were obtained on these yarns at conventional rates of straining and under conditions involving transverse and longi tudinal impact at velocities near 40 m/sec. Strain-wave velocities were also measured. The effects of twisting and braiding were the same at high rates of straining and at conventional rates of straining. The addition of twist or braid caused the following effects. The initial slope of the stress-strain curve and the strain-wave velocity de creased. The bend in the curve at the yield stress became less sharp so that the stress- strain curve became more linear. The breaking tenacity decreased and the breaking elongation increased. The work required to break a unit mass of yarn material re mained unchanged. The calculated value of the longitudinal critical velocity at which a specimen breaks immediately upon impact in tension remained unchanged. Calculated transverse critical velocities tended to decrease as the yarn was twisted or braided.