Year: 1954
Type: report
Abstract: An experimental study was made to determine the effects of strain rate, temperature, type of notch, and size of specimen on four steels tested in torsion.Unnotched specimens were 14 in. in diameter and the root diameters of notched specimens were 16 in.and % in.Two sharpnesses of notch were used giving ratios of notch radius to root diameter, r/D, of 0.160 and 0.053.Three rates of torsional strain were obtained by using angular velocities of 0.5 rpm, 27 rpm, and 1300 rpm for the flywheel which loaded the specimen.The tests were conducted at -100 F, room temperature, and 700 F.Torque, angle of twist, and time were continuously recorded and torsional properties were determined.In general it was found that, for ranges of strain rate and temperature used, an increase in strain rate caused no appreciable change in strength but did cause a decrease in ductility and total energy absorbed.An increase in temperature caused a decrease in strength and energy that 'were accompanied by a decrease in ductility at low strain rates and an increase in ductility at high strain rates.There was a decrease in ultimate strength with increased size of specimen.Size effect as measured by energy considerations increased with an increase in speed and a decrease in temperature.A study was also made of the energy conditions governing the onset of unstable fracturing.
Authors: P.G. Jones, Thomas J. Dolan
Language: English
Subfield: Mechanics of Materials
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W30788363