Shear Strains, Strain Rates and Temperature Changes in Adiabatic Shear Bands
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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Experiments were conducted to determine the shear strains and strain rates in adiabatic shear bands in a Ni-Cr steel rolled armor. An explosively driven mass was used to punch plugs from plate of the steel and, thereby, create adiabatic shear bands. There were originally planes of chemical inhomogeneity reference bands in the plane of the steel samples. The slopes of the reference bands were altered by the plastic shear, and they were, therefore, a measure of the plastic shear strain. From measurements of the slopes of the reference bands, it was found that the plastic shear was approximately an exponential function of distance through an adiabatic shear band. Shear strains of at least 572 developed after the onset of adiabatic shear. The results suggest how heating occurs within the shear bands, the maximum temperatures attained and the related strength degradation associated with the development of an adiabatic shear band.