Response of Various Metals to Large Torsional Strains Over a Large Range of Strain Rates—Part 1: Ductile Metals

This paper presents torsional test results for six ductile metals subjected to large shear strains and high strain rates. Included are OFHC copper, Cartridge brass, Nickel 200, Armco IF iron, Carpenter electrical iron, and 1006 steel. Torsional shear strains as high as 700 percent are achieved and strain rates vary from quasi-static to over 300 s−1. At the lower strain rates all of the materials exhibit positive strain hardening and strain rate hardening under essentially isothermal conditions. At the higher strain rates there is significant adiabatic thermal softening and strong evidence for shear instabilities and localizations. Constitutive relationships are derived from the test data and finite element computations of the tests are performed.