Analytical shear-band process zone model incorporating nonlinear viscous effects and initial defects

Fuente: arXiv
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Main Author: Clayton, John D.
Format: Preprint
Published: 2025
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author Clayton, John D.
author_facet Clayton, John D.
contents Experimental, theoretical, and numerical studies of adiabatic shear in ductile metals suggest initial defects such as pores or material imperfections increase shear-band susceptibility. Conversely, viscous effects manifesting macroscopically as strain-rate sensitivity inhibit localization. The analytical shear-band process zone model due to D.E. Grady, in turn based on a rigid-plastic solution for stress release by N.F. Mott, is advanced to account for these phenomena. The material contains an average defect measure (e.g., porosity) and a concentrated defect measure at a spatial location where shear banding is most likely to initiate after an instability threshold is attained. Shearing resistance and certain physical properties are reduced commensurately with local defect concentration. Non-Newtonian viscosity increases dissipative resistance. Viscous dissipation, if strong enough, is shown to prevent an infinitesimal-width shear band even in a non-conductor. Here, a pseudo-quadratic viscosity widens the band similarly to heat conduction, and akin to quadratic shock viscosity often used to resolve widths of planar shock waves. The model captures simulation data showing reduced localization strain and shear band width with increasing maximum initial pore size in additively manufactured titanium and HY-100 steel. Predictions for shear band width, local strain, and temperature are more accurate versus data on steel than prior analytical modeling. A quantitative framework is established by which processing defects can be related to shear-banding characteristics.
format Preprint
id arxiv_https___arxiv_org_abs_2503_06033
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Analytical shear-band process zone model incorporating nonlinear viscous effects and initial defects
Clayton, John D.
Materials Science
74H10 (primary), 74C20, 74E05, 74R20 (secondary)
Experimental, theoretical, and numerical studies of adiabatic shear in ductile metals suggest initial defects such as pores or material imperfections increase shear-band susceptibility. Conversely, viscous effects manifesting macroscopically as strain-rate sensitivity inhibit localization. The analytical shear-band process zone model due to D.E. Grady, in turn based on a rigid-plastic solution for stress release by N.F. Mott, is advanced to account for these phenomena. The material contains an average defect measure (e.g., porosity) and a concentrated defect measure at a spatial location where shear banding is most likely to initiate after an instability threshold is attained. Shearing resistance and certain physical properties are reduced commensurately with local defect concentration. Non-Newtonian viscosity increases dissipative resistance. Viscous dissipation, if strong enough, is shown to prevent an infinitesimal-width shear band even in a non-conductor. Here, a pseudo-quadratic viscosity widens the band similarly to heat conduction, and akin to quadratic shock viscosity often used to resolve widths of planar shock waves. The model captures simulation data showing reduced localization strain and shear band width with increasing maximum initial pore size in additively manufactured titanium and HY-100 steel. Predictions for shear band width, local strain, and temperature are more accurate versus data on steel than prior analytical modeling. A quantitative framework is established by which processing defects can be related to shear-banding characteristics.
title Analytical shear-band process zone model incorporating nonlinear viscous effects and initial defects
topic Materials Science
74H10 (primary), 74C20, 74E05, 74R20 (secondary)
url https://arxiv.org/abs/2503.06033