A criterion for the onset of void coalescence under combined tension and shear

Tekoğlu, Cihan; Leblond, Jean-Baptiste; Pardoen, Thomas

doi:10.1016/j.jmps.2012.02.006

Cited by 96 publications

(54 citation statements)

References 41 publications

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“…This model has been extended in various directions to account for phenomena not included in its original version, notably void shape effects (Gologanu et al, 1993(Gologanu et al, , 1994Garajeu et al, 2000;Leblond, 2012a,b, 2013;, plastic anisotropy (Benzerga and Besson, 2001;Monchiet et al, 2008;Keralavarma and Benzerga, 2010;Morin et al, 2015c) and void coalescence (Thomason, 1985;Tekoglu et al, 2012;Benzerga and Leblond, 2014;Morin et al, 2015b). It has met, in both its original and improved forms, considerable success in the reproduction of experimental tests of failure of ductile materials under monotonic loading conditions.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

A Gurson-type layer model for ductile porous solids with isotropic and kinematic hardening

Morin

Michel

Leblond

2017

International Journal of Solids and Structures

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The aim of this work is to propose a Gurson-type model for ductile porous solids exhibiting isotropic and kinematic hardening. The derivation is based on a "sequential limit-analysis" of a hollow sphere made of a rigid-hardenable material. The heterogeneity of hardening is accounted for by discretizing the cell into a finite number of spherical layers in each of which the quantities characterizing hardening are considered as homogeneous. A simplified version of the model is also proposed, which permits to extend the previous works of Leblond et al. (1995) andLacroix et al. (2016) for isotropic hardening to mixed isotropic/kinematic hardening. The model is finally assessed through comparison of its predictions with the results of some micromechanical finite element simulations of the same cell. First, the numerical and theoretical overall yield loci are compared for given distributions of isotropic and kinematic pre-hardening. Then the predictions of the model are investigated in evolution problems in which both isotropic and kinematic hardening parameters vary in time. A very good agreement between model predictions and numerical results is found in both cases.

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Section: Accepted Manuscriptmentioning

confidence: 99%

A Gurson-type layer model for ductile porous solids with isotropic and kinematic hardening

Morin

Michel

Leblond

2017

International Journal of Solids and Structures

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“…Even when presence of other phases such as retained austenite or bainite are not taken into account, the micromechanical behavior of the composite-like dual phase microstructure of DP http://dx.doi.org/10.1016/j.ijplas.2014.06.004 0749-6419/Ó 2014 Elsevier Ltd. All rights reserved. steels is rather complex (Tekoglu and Pardoen, 2010, Tekoglu et al, 2012, Kadkhodapour et al, 2011b,2011a, Sun et al, 2009a,2009b. Thus, following numerous reports on the mechanical performance of DP steel (which are typically based on conventional post-mortem microstructure characterization techniques), the microstructural strain and stress partitioning that governs the overall behavior of DP microstructures is still not fully understood.…”

Section: Introductionmentioning

confidence: 99%

Strain localization and damage in dual phase steels investigated by coupled in-situ deformation experiments and crystal plasticity simulations

Taşan

Hoefnagels

Diehl

et al. 2014

International Journal of Plasticity

429

176

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a b s t r a c tFerritic-martensitic dual phase (DP) steels deform spatially in a highly heterogeneous manner, i.e. with strong strain and stress partitioning at the micro-scale. Such heterogeneity in local strain evolution leads in turn to a spatially heterogeneous damage distribution, and thus, plays an important role in the process of damage inheritance and fracture. To understand and improve DP steels, it is important to identify connections between the observed strain and damage heterogeneity and the underlying microstructural parameters, e.g. ferrite grain size, martensite distribution, martensite fraction, etc. In this work we pursue this aim by conducting in-situ deformation experiments on two different DP steel grades, employing two different microscopic-digital image correlation (lDIC) techniques to achieve microstructural strain maps of representative statistics and high-resolution. The resulting local strain maps are analyzed in connection to the observed damage incidents (identified by image post-processing) and to local stress maps (obtained from crystal plasticity (CP) simulations of the same microstructural area). The results reveal that plasticity is typically initiated within ''hot zones'' with larger ferritic grains and lower local martensite fraction. With increasing global deformation, damage incidents are most often observed in the boundary of such highly plastified zones. High-resolution lDIC and the corresponding CP simulations reveal the importance of martensite dispersion: zones with bulky martensite are more susceptible to macroscopic localization before the full strain hardening capacity of the material is consumed. Overall, the presented joint analysis establishes an integrated computational materials engineering (ICME) approach for designing advanced DP steels.

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“…One of the primary aims of the present paper is to clarify the distinction between mechanisms 3 and 4 and to ascertain when they occur separately or simultaneously. Void coalescence has received a considerable attention in recent years with significant refinements of the early models of Thomason [36], as illustrated in references [28,31]. Void coalescence has also been incorporated in an ad hoc manner in the continuum models for porous elastic-plastic solids [5].…”

Section: Introductionmentioning

confidence: 99%

On localization and void coalescence as a precursor to ductile fracture

Tekoğlu

Hutchinson

Pardoen

2015

Phil. Trans. R. Soc. A.

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126

110

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Two modes of plastic flow localization commonly occur in the ductile fracture of structural metals undergoing damage and failure by the mechanism involving void nucleation, growth and coalescence. The first mode consists of a macroscopic localization, usually linked to the softening effect of void nucleation and growth, in either a normal band or a shear band where the thickness of the band is comparable to void spacing. The second mode is coalescence with plastic strain localizing to the ligaments between voids by an internal necking process. The ductility of a material is tied to the strain at macroscopic localization, as this marks the limit of uniform straining at the macroscopic scale. The question addressed is whether macroscopic localization occurs prior to void coalescence or whether the two occur simultaneously. The relation between these two modes of localization is studied quantitatively in this paper using a three-dimensional elastic-plastic computational model representing a doubly periodic array of voids within a band confined between two semi-infinite outer blocks of the same material but without voids. At sufficiently high stress triaxiality, a clear separation exists between the two modes of localization. At lower stress triaxialities, the model predicts that the onset of macroscopic localization and coalescence occur simultaneously.

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A criterion for the onset of void coalescence under combined tension and shear

Cited by 96 publications

References 41 publications

A Gurson-type layer model for ductile porous solids with isotropic and kinematic hardening

A Gurson-type layer model for ductile porous solids with isotropic and kinematic hardening

Strain localization and damage in dual phase steels investigated by coupled in-situ deformation experiments and crystal plasticity simulations

On localization and void coalescence as a precursor to ductile fracture

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