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Main Authors: Singh, Siddharth, Arora, Rajat, Wanni, Janith, Adkins, Charles, Rasmussen, Raymond, Schmelzer, Noah J., Thoma, Dan J., Bronkhorst, Curt A., Acharya, Amit
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2605.17619
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author Singh, Siddharth
Arora, Rajat
Wanni, Janith
Adkins, Charles
Rasmussen, Raymond
Schmelzer, Noah J.
Thoma, Dan J.
Bronkhorst, Curt A.
Acharya, Amit
author_facet Singh, Siddharth
Arora, Rajat
Wanni, Janith
Adkins, Charles
Rasmussen, Raymond
Schmelzer, Noah J.
Thoma, Dan J.
Bronkhorst, Curt A.
Acharya, Amit
contents Dynamic shear banding under adiabatic conditions in a mesoscale polycrystalline aggregate is studied using a model of mesoscale dislocation mechanics and experiments. The model involves a length scale related to hardening induced by excess/polar/geometrically necessary dislocation (GND) density, and utilizes a simple classical crystal plasticity model with isotropic Voce law hardening. Simulations of statistically representative volume elements of a polycrystal determined from experimental samples are conducted. Studies in 2-d (section) and 3-d capture the experimentally observed finite-width shear bands and the formation of low-angle subgrain boundaries even in the absence of heat conduction in the model, as well as size-dependent strengthening for grain sizes from 1 to 20 $μ$m. The 2-d and large-scale 3-d simulations, the latter involving 1 million finite elements, provide access to the progressive evolution of material strength, stress state, and temperature in the course of large deformations. GND distributions accumulate at grain boundaries and form patterned structures within grain interiors, offering insight into the microstructural changes that precede failure in adiabatic shear bands. Mesh-converged, delocalized and localized plastic flow to very large deformations without softening is observed for a significant range of parameters, reflecting a competition between GND hardening and thermal softening in setting the non-softening steady state in the absence of other ductile damage mechanisms in the model.
format Preprint
id arxiv_https___arxiv_org_abs_2605_17619
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Finite-width adiabatic shear banding and dislocation patterning in mesoscale polycrystalline aggregates
Singh, Siddharth
Arora, Rajat
Wanni, Janith
Adkins, Charles
Rasmussen, Raymond
Schmelzer, Noah J.
Thoma, Dan J.
Bronkhorst, Curt A.
Acharya, Amit
Materials Science
Dynamic shear banding under adiabatic conditions in a mesoscale polycrystalline aggregate is studied using a model of mesoscale dislocation mechanics and experiments. The model involves a length scale related to hardening induced by excess/polar/geometrically necessary dislocation (GND) density, and utilizes a simple classical crystal plasticity model with isotropic Voce law hardening. Simulations of statistically representative volume elements of a polycrystal determined from experimental samples are conducted. Studies in 2-d (section) and 3-d capture the experimentally observed finite-width shear bands and the formation of low-angle subgrain boundaries even in the absence of heat conduction in the model, as well as size-dependent strengthening for grain sizes from 1 to 20 $μ$m. The 2-d and large-scale 3-d simulations, the latter involving 1 million finite elements, provide access to the progressive evolution of material strength, stress state, and temperature in the course of large deformations. GND distributions accumulate at grain boundaries and form patterned structures within grain interiors, offering insight into the microstructural changes that precede failure in adiabatic shear bands. Mesh-converged, delocalized and localized plastic flow to very large deformations without softening is observed for a significant range of parameters, reflecting a competition between GND hardening and thermal softening in setting the non-softening steady state in the absence of other ductile damage mechanisms in the model.
title Finite-width adiabatic shear banding and dislocation patterning in mesoscale polycrystalline aggregates
topic Materials Science
url https://arxiv.org/abs/2605.17619