Stress-Strain Relationships in Yarns Subjected to Rapid Impact Loading

If a textile yarn segment, clamped at each end, is impacted transversely at the mid point, the stress-strain curve for this yarn can be obtained from measurements on a high speed photographic record of the yarn's motion. This paper describes the apparatus and procedure used. Stress-strain curves for high rates of straining, of the order 5000%/sec., obtained by this method are given for high tenacity nylon, Fortisan, and Fiberglas. Comparison with stress-strain data obtained at conventional rates shows that these mate rials have higher initial moduli, and that their stress-strain curves remain linear up to higher stress values, when the testing rate is high. The breaking tenacities are slightly greater and breaking elongation slightly smaller at these high test rates.