The effect of specimen dimensions on the propensity to adiabatic shear failure in kolsky bar experiments

Abstract

The issue of adiabatic shearing is discussed in this work and a new interpretation is given to some failure phenomena which are usually termed as adiabatic shears. We propose that only a few materials undergo a truly inherent failure which is due to thermal softening at the shearing zone and that the interplay between microvoids, cracks and narrow shear bands should be taken into account through the temperature rise at the front of advancing cracks. Also, the size of the plastic zone ahead of a crack plays an important role in determining the brittleness of a given specimen and should be taken into account when specimens of different sizes are tested. Experimental results for several alloys in the Kolsky bar system support our approach.