Author: Robert J. Coskren
Publisher:
Published: 1968
Total Pages: 130
ISBN-13:
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Four newly developed fibers (PBI, X-101, PRD-14 and Beta glass) were evaluated in webbing form (3000-9000 lbs breaking strength) for rupture energy absorption capacity at 200,500, and 700 ft/sec (strain rates of 8,000; 20,000 and 28,000%/sec based upon an initial 2.5 foot gage length). The dynamic energy absorption capability of the PRD-14 webbing is essentially unchanged over the entire speed range studied. The rupture energy of the X-101 webbing is diminished by 20% as testing speed is increased up to 500 ft/sec and then exhibits a loss of approximately 70% at 700 ft/sec. The PBI exhibits a 50% loss from quasi-static up to the 500 ft/sec testing speed and diminishes to approximately 10% of quasi-static at 700 ft/sec. The energy level of the Beta glass improves or remains almost unchanged in the entire speed range. Generally, however, this level is of such a low order that the usefulness of Beta glass is limited to cases where exposure to elevated temperatures in excess of 850F may be anticipated. Six fibers were evaluated in tape form (300-675 lbs breaking strength) for energy absorption capacity at speeds of 50, 100 and 150 ft/sec (strain rates of 1,111; 2,222 and 3,333%/sec) at various temperatures. To obtain a basis for comparison, quasi-static (Instron) tests were also performed at corresponding temperatures. Results indicate that, within the precision of the equipment at 70F, most materials are only slightly sensitive to strain rate over the high-speed range studied. (Author).
