A METHOD FOR DETERMINING THE TENSILE PROPERTIES OF METALS AT HIGH RATES OF STRAIN

Journal Article · Thu Jan 01 04:00:00 EST 1959 · Proc. Soc. Exptl. Stress Anal.

OSTI ID:4189367

Austin, A L; Steidel, Jr, R F

An experimental method was developed to determine the dynamic tensile properties of materials at the high rates of strain experienced during the final stages of plastic deformation to fracture. An explosive impact tensile tester was designed with provisions for direct and accurate measurements of load, impact velocity, and instuntaneous changes of diameter as a function of time. A charge of gunpowder was used to propel a projectile threaded to one end of a specimen, the other end being fixed. A load-time history was obtained from an oscilloscope record of the output of two resistance wire strain gages mounted at the fixed end of the specimen. With siInouette lighting, a high speed framing camera operating at 170,000 frames per second was used to photograph the specimen over the interval of time from necking to fracture providing a permanent visual record of the instantaneous change of diameter with time. By this method dynamic stress- strain curves were obtained for various trne strain rates. Data for steel and aluminum alloy were obtained to verify the experimental apparatus and method. These data consisted of fracture stresses, impact velocity, reduction of area, total elongation, and strain rate. Dynamic stress-strain curves for these materials indicated that strength increases with strain rate at room temperature. The tensile properties of these materials were obtained for strain rates as high as 17,000 in./in./sec by this method. (auth)

• Research Organization: Univ. of California, Berkeley
• NSA Number: NSA-14-014103
• OSTI ID: 4189367
• Journal Information: Proc. Soc. Exptl. Stress Anal., Journal Name: Proc. Soc. Exptl. Stress Anal. Vol. Vol: 17
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALUMINUM ALLOYS
CAMERAS
DEFORMATION
DIAGRAMS
DUCTILITY
EFFICIENCY
EXPLOSIVES
FAILURES
IMPACT SHOCK
LABORATORY EQUIPMENT
MATERIALS TESTING
MEASURED VALUES
METALS, CERAMICS, AND OTHER MATERIALS
OSCILLOGRAPHS
PLANNING
PRESSURE
PROPULSION
QUANTITATIVE ANALYSIS
RECORDING SYSTEMS
STEELS
STRESSES
TEMPERATURE
TENSILE PROPERTIES
THICKNESS
VARIATIONS
VELOCITY
WIRES