DISSIPATION IN ADIABATIC SHEAR BANDS

In the present study of adiabatic shear banding in metals, the region of interest is modelled as a two-material two-temperature body. Specific material laws governing thermoviscous plasticity and heat transfer are ascribed to the shear-band zone. Momentum and energy balance lead to a system of one-dimensional ordinary differential equations describing the dynamics of the shear localization process. The propagating shear band is viewed as having two distinct regions. The first is the shear-band tip process zone within which adiabatic heating, thermal softening and all shear dissipation are considered to occur. The second is the late-time quasi-steady zone in which the shear stress and dissipation rate are close to zero. The analysis provides the width and displacement of the shear-band process zone. In addition, criteria for assessing material shear-banding resistance are investigated in terms of a shear-band dissipation rate, or a shear-band toughness. Shear-band dissipation and shear-band toughness for a number of metals are calculated and compared.