Experimental Studies of Shear Band Formation Through Temperature Measurements and High Speed Photography

Duffy, J.

doi:10.1051/jp4:1991390

Cited by 5 publications

(1 citation statement)

References 4 publications

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“…Several applications of this phenomenon follow from the mechanisms of transformation of the intense plastic shear to failure that is characteristic for shock impact loading, ballistic penetration, fragmentation, machining, explosive forming, [2,3]. The ASB definition is related to high strain rates, when temperature rise can be qualified as adiabatic [4][5][6][7][8][9][10]. The pioneering experimental study by Marchand and Duffy [7] established a three stages of ASB failure, starting from a homogeneous strain state transforming into the inhomogeneous strain distribution with following narrowing as the precursor of failure.…”

Section: Introductionmentioning

confidence: 99%

Metastability, adiabatic shear bands initiation and plastic strain localization in the AMg6 alloy under dynamic loading

Sokovikov,

Uvarov,

Simonov

et al. 2024

Frattura Ed Integrità Strutturale

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New conception of adiabatic shear bands (ASB) and adiabatic shear failure mechanisms are proposed as special type of critical phenomen, structural-scaling transition, in the ensembles of microshears, governed by the characteristic non-linearity (metastability) of stored (free) energy of solid with mesodefects. Corresponding free energy release kinetics provides experimentally observed ASB induced staging of plastic strain localization and transition to adiabatic shear failure. ASB staging follows to collective properties of microshears ensemble given by the self-similar solutions of evolution equation providing spatial-temporal microshears localization, momentum transfer and damage localization. The criticality of ASB induced plastic strain localization and failure allows us to avoid the discrepancy in the interpretation of ASB effects as thermo-plastic instability in the balance of the stored energy and structural DRX transformation. The microshear ensemble is considered as the second phase and initiation of collective modes provide different staging according to the metastability decomposition and ASB scaling properties following to the self-similar solutions. Self-similar nature of microshears collective modes providing the ASB dynamics is analyzed as the mechanism of steady plastic wave front unversality in shocked materials. The dynamic split Hopkinson pressure bar tests were conducted with AlMg6 alloy combined with “in-situ” imaging of temperature kinetics by CEDIP Silver 450M high-speed infrared camera with conclusion of the secondary role of thermoplastic instability at the ASB staging. The microstructural study performed by an electron microscopy revealed the correlated behavior of the ensemble of defects, which can be classified as a structural transition and precursor of ASB induced strain localization and failure. The modeling reflecting the links of self-similar solutions in microshear ensembles with relaxation properies and damage localization was applied for the comparative analysis of ASB staging and temperature dynamics given be the infrared imaging.

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Section: Introductionmentioning

confidence: 99%

Metastability, adiabatic shear bands initiation and plastic strain localization in the AMg6 alloy under dynamic loading

Sokovikov,

Uvarov,

Simonov

et al. 2024

Frattura Ed Integrità Strutturale

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2012

Adiabatic Shear Localization

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Dynamic shear instabilities in metallic sheets subjected to shear-compression loading

Rodríguez-Martínez

Vaz-Romero

N'souglo

et al. 2020

Journal of the Mechanics and Physics of Solids

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This paper presents an investigation on the formation of adiabatic shear bands in metallic sheets subjected to dynamic shear-compression loading under plane-stress conditions. For that purpose, we have developed a theoretical model based on perturbation analysis, and have performed finite element calculations. The material behavior has been modeled with von Mises plasticity, and the evolution of the yield stress has been considered dependent on plastic strain, plastic strain rate, and temperature. The theoretical model extends the linear stability analysis for simple-shear formulated by Molinari (1997) to shear-compression loading. The numerical simulations have been performed in ABAQUS/Explicit (2016) using a unit-cell model based on the work of Rodríguez-Martínez et al. (2015) in which the shear band formation is favored introducing geometric and material imperfections. Moreover, we have developed a calibration procedure for the stability analysis that enables to make qualitative and quantitative comparisons with the finite element calculations. Both stability analysis predictions and finite element results display the same overall trends, and show that any small negative triaxiality has a profound stabilizing effect on the material behavior delaying, or even preventing, the formation of a shear band. This key outcome has been substantiated for a wide range of strain rates and for materials with different strain hardening coefficients, strain rate sensitivities, and thermal softening behaviors.

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Experimental Studies of Shear Band Formation Through Temperature Measurements and High Speed Photography

Cited by 5 publications

References 4 publications

Metastability, adiabatic shear bands initiation and plastic strain localization in the AMg6 alloy under dynamic loading

Metastability, adiabatic shear bands initiation and plastic strain localization in the AMg6 alloy under dynamic loading

Bibliography

Dynamic shear instabilities in metallic sheets subjected to shear-compression loading

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