Estimation of energy dissipation during dynamic shear band evolution

Abstract

The adiabatic shear band (ASB) criterion is crucial for assessing the shear failure resistance of metals and alloys under dynamic loading. While the critical shear strain obtained from macroscopic stress–strain curves has been widely employed to predict ASB nucleation, it cannot describe the subsequent ASB evolution process, which occurs at extreme spatial (∼µm) and temporal (∼µs) scales. In this work, we introduce a generalized shear band toughness to characterize the post-localization energy dissipation within the band, which can be estimated from temperature fields captured by high-speed, high-resolution infrared thermal detectors. The generalized shear band toughness model accounts for contributions from both thermal softening and microstructure-related softening mechanisms in ASB evolution. We systematically characterize the shear band toughness across a range of materials, from conventional alloys to advanced high-entropy alloys. Finally, the shear band toughness is incorporated into a dual-stage, energy-based shear banding criterion, which proves crucial for accurately predicting the entire shear banding process, particularly in scenarios involving dynamic shear band propagation in large structures.