Direct evidence of plastic events and dynamic heterogeneities in soft-glasses

Benzi, Roberto; Sbragaglia, Mauro; Perlekar, Prasad; Bernaschi, Massimo; Succi, Sauro; Toschi, Federico

doi:10.1039/c4sm00348a

Cited by 29 publications

(64 citation statements)

References 51 publications

(169 reference statements)

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“…Therefore we can conclude that the system displays strong correlations in space. The same feature is observed using the overlap-overlap correlation function as discussed in [3].…”

Section: Numerical Simulationssupporting

confidence: 72%

On interevent time distributions of avalanche dynamics

Kumar

Korkolis

Benzi

et al. 2020

Sci Rep

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Physical systems characterized by stick-slip dynamics often display avalanches. Regardless of the diversity of their microscopic structure, these systems are governed by a power-law distribution of avalanche size and duration. Here we focus on the interevent times between avalanches and show that, unlike their distributions of size and duration, the interevent time distributions are able to distinguish different mechanical states of the system, characterized by different volume fractions or confining pressures. We use experiments on granular systems and numerical simulations of emulsions to show that systems having the same probability distribution for avalanche size and duration can have different interevent time distributions. Remarkably, for large packing ratios, these interevent time distributions look similar to those for earthquakes and are indirect evidence of large space-time correlations in the system. Our results therefore indicate that interevent time statistics are more informative to characterize the dynamics of avalanches. arXiv:1906.09897v1 [cond-mat.soft]

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“…Therefore we can conclude that the system displays strong correlations in space. The same feature is observed using the overlap-overlap correlation function as discussed in [3].…”

Section: Numerical Simulationssupporting

confidence: 72%

On interevent time distributions of avalanche dynamics

Kumar

Korkolis

Benzi

et al. 2020

Sci Rep

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“…More generally, it seems likely that in the future the study of plastic correlations, as described in Ref. [17,18] or in the present work, will become a powerful tool for comparison between models of various types and between models and experiments in systems in which the corresponding observables are experimentally accessible.…”

Section: Discussionmentioning

confidence: 99%

Spatiotemporal correlations between plastic events in the shear flow of athermal amorphous solids

2014

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Abstract. The slow flow of amorphous solids exhibits striking heterogeneities: swift localised particle rearrangements take place in the midst of a more or less homogeneously deforming medium. Recently, experimental as well as numerical work has revealed spatial correlations between these flow heterogeneities. Here, we use molecular dynamics (MD) simulations to characterise the rearrangements and systematically probe their correlations both in time and in space. In particular, these correlations display a four-fold azimuthal symmetry characteristic of shear stress redistribution in an elastic medium and we unambiguously detect their increase in range with time. With increasing shear rate, correlations become shorter-ranged and more isotropic. In addition, we study a coarse-grained model motivated by the observed flow characteristics and challenge its predictions directly with the MD simulations. While the model captures both macroscopic and local properties rather satisfactorily, the agreement with respect to the spatiotemporal correlations is at most qualitative. The discrepancies provide important insight into relevant physics that is missing in all related coarse-grained models that have been developed for the flow of amorphous materials so far, namely the finite shear wave velocity and the impact of elastic heterogeneities on stress redistribution.

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“…Recent examples include density excitations (determining frictional properties) in driven colloidal monolayers [1][2][3][4], the stick-slip motion involved in the transmission of torque in driven colloidal clutches [5], as well as heterogeneities [6][7][8][9], and diverging stress-and strain correlations [6,10] in sheared colloidal glasses. Related complex microscopic behavior occurs in sheared granular matter [11] and sheared suspensions of non-Brownian particles [12].…”

Section: Introductionmentioning

confidence: 99%

Depinning and heterogeneous dynamics of colloidal crystal layers under shear flow

Gerloff¹,

Klapp²

2016

Phys. Rev. E

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Using Brownian dynamics (BD) simulations and an analytical approach we investigate the shearinduced, nonequilibrium dynamics of dense colloidal suspensions confined to a narrow slit-pore. Focusing on situations where the colloids arrange in well-defined layers with solidlike in-plane structure, the confined films display complex, nonlinear behavior such as collective depinning and local transport via density excitations. These phenomena are reminiscent of colloidal monolayers driven over a periodic substrate potential. In order to deepen this connection, we present an effective model which maps the dynamics of the shear-driven colloidal layers to the motion of a single particle driven over an effective substrate potential. This model allows to estimate the critical shear rate of the depinning transition based on the equilibrium configuration, revealing the impact of important parameters such as the slit-pore width and the interaction strength. We then turn to heterogeneous systems where a layer of small colloids is sheared with respect to bottom layers of large particles. For these incommensurate systems we find that the particle transport is dominated by density excitations resembling the so-called "kink" solutions of the Frenkel-Kontorova (FK) model. In contrast to the FK model, however, the corresponding "antikinks" do not move.

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Direct evidence of plastic events and dynamic heterogeneities in soft-glasses

Cited by 29 publications

References 51 publications

On interevent time distributions of avalanche dynamics

On interevent time distributions of avalanche dynamics

Spatiotemporal correlations between plastic events in the shear flow of athermal amorphous solids

Depinning and heterogeneous dynamics of colloidal crystal layers under shear flow

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