Thermally activated flow in models of amorphous solids

Popović, Marko; Geus, Tom W. J. de; Ji, Wencheng; Wyart, Matthieu

doi:10.1103/physreve.104.025010

Cited by 13 publications

(11 citation statements)

References 41 publications

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“…We use a finiteelement solver to propagate stresses from fluidized sites, which automatically produces the anisotropic Eshelbylike stress-fields characteristic of STs. In contrast to the other thermally activated EPMs [36][37][38], we use a realspace stress-propagator more similar to [17,44]. In some of our simulations, we follow refs.…”

Section: Thermally Activated Elastoplastic Modelmentioning

confidence: 99%

“…Computational studies of thermal activation effects on the yielding transition have been conducted with molecular dynamics simulations of glass formers [35] and more recently with mesoscale elastoplastic models (EPM) [36][37][38]. In overdamped systems in general, the flow stress decreases with temperature and increases with driving rate.…”

Section: Introductionmentioning

confidence: 99%

“…To that end, in this work we will use a mesoscale model with Arrhenius activation rule (as in refs. [36][37][38])…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dynamic phase diagram of plastically deformed amorphous solids at finite temperature

Korchinski,

Rottler

2022

Preprint

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The yielding transition that occurs in amorphous solids under athermal quasistatic deformation has been the subject of many theoretical and computational studies. Here, we extend this analysis to include thermal effects at finite shear rate, focusing on how temperature alters avalanches. We derive a nonequilibrium phase diagram capturing how temperature and strain rate effects compete, when avalanches overlap, and whether finite-size effects dominate over temperature effects. The predictions are tested through simulations of an elastoplastic model in two dimensions and in a mean-field approximation. We find a new scaling for temperature-dependent softening in the lowstrain rate regime when avalanches do not overlap, and a temperature-dependent Herschel-Bulkley exponent in the high strain rate regime when avalanches do overlap.

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Section: Thermally Activated Elastoplastic Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamic phase diagram of plastically deformed amorphous solids at finite temperature

Korchinski,

Rottler

2022

Preprint

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“…The general assumption is that upon loading the weakest spots of the material get subsequently activated. The idea that microstructural heterogeneity affects plasticity through the variations in local strength led to the development of mesoscopic elasto-plastic models for both amorphous [32][33][34][35][36][37][38][39] and crystalline [40,41] materials. In these models whenever the local stress at a given grid cell exceeds the local threshold, plastic strain is accumulated in that cell giving rise to the anisotropic redistribution of the internal stress that may lead to subsequent activation of another cell.…”

mentioning

confidence: 99%

“…Secondly, this selection is also motivated by experiments, e.g., during nanoindentation, a method used to determine local strength, a local volume is loaded rather than individual dislocations. Thirdly, usually similar rectangular grids are used in mesoscale simulations [32][33][34][35]38] and in continuum dislocation field theories as well [42,[51][52][53][54][55]. Thus, local yield stress statistics (distribution, spatial correlations, etc.)…”

mentioning

confidence: 99%

Dynamic Length Scale and Weakest Link Behavior in Crystal Plasticity

Berta¹,

Péterffy²,

Ispánovity³

2022

Preprint

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Plastic deformation of heterogeneous solid structures is often characterized by random intermittent local plastic events. On the mesoscale this feature can be represented by a spatially fluctuating local yield threshold. Here we study the validity of such an approach and the ideal choice for the size of the representative volume element for crystal plasticity in terms of a discrete dislocation model. We find that the number of links representing possible sources of plastic activity exhibits anomalous (super-extensive) scaling which tends to extensive scaling (often assumed in weakestlink models) if quenched short-range interactions are introduced. The reason is that the interplay between long-range dislocation interactions and short-range quenched disorder destroys scale-free dynamical correlations leading to event localization with a characteristic length-scale. Several methods are presented to determine the dynamic length-scale that can be generalized to other types of heterogeneous materials.

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Local vs. cooperative: Unraveling glass transition mechanisms with SEER

Pica Ciamarra,

Ji,

Wyart

2024

Proc. Natl. Acad. Sci. U.S.A.

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Which phenomenon slows down the dynamics in supercooled liquids and turns them into glasses is a long-standing question of condensed matter. Most popular theories posit that as the temperature decreases, many events must occur in a coordinated fashion on a growing length scale for relaxation to occur. Instead, other approaches consider that local barriers associated with the elementary rearrangement of a few particles or “excitations” govern the dynamics. To resolve this conundrum, our central result is to introduce an algorithm, Systematic Excitation ExtRaction, which can systematically extract hundreds of excitations and their energy from any given configuration. We also provide a measurement of the activation energy, characterizing the liquid dynamics, based on fast quenching and reheating. We use these two methods in a popular liquid model of polydisperse particles. Such polydisperse models are known to capture the hallmarks of the glass transition and can be equilibrated efficiently up to millisecond time scales. The analysis reveals that cooperative effects do not control the fragility of such liquids: the change of energy of local barriers determines the change of activation energy. More generally, these methods can now be used to measure the degree of cooperativity of any liquid model.

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Thermally activated flow in models of amorphous solids

Cited by 13 publications

References 41 publications

Dynamic phase diagram of plastically deformed amorphous solids at finite temperature

Dynamic phase diagram of plastically deformed amorphous solids at finite temperature

Dynamic Length Scale and Weakest Link Behavior in Crystal Plasticity

Local vs. cooperative: Unraveling glass transition mechanisms with SEER

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