In this work we calculate the local elastic moduli in a weakly polydispersed two-dimensional Lennard-Jones glass undergoing quasistatic shear deformation at zero temperature. The numerical method uses coarse-grained microscopic expressions for strain, displacement, and stress fields. This allows us to elasticity tensor quantify deviation from linear (local Hooke's law) different coarse-graining scales. From results clear picture emerges of an amorphous material with strongly spatially...

We review the recent literature on simulation of structure and deformation amorphous solids, including oxide metallic glasses. consider simulations at different length scale time scale. At nanometer scale, we studies based atomistic simulations, with a particular emphasis role potential energy landscape temperature. micrometer present mesoscopic models plasticity show relation between shear banding type disorder correlations (e.g. elastic) included in models. macroscopic range, constitutive...

The approach of the elastic continuum limit in small amorphous bodies formed by weakly polydisperse Lennard-Jones beads is investigated a systematic finite-size study. We show that classical elasticity breaks down when wavelength sollicitation smaller than characteristic length approximately 30 molecular sizes. Due to this surprisingly large effect ensembles containing up N=40,000 particles have been required two dimensions yield convincing match with predictions for eigenfrequency spectrum...

Extending recent numerical studies on two-dimensional amorphous bodies, we characterize the approach of elastic continuum limit in three-dimensional (weakly polydisperse) Lennard-Jones systems. While performing a systematic finite-size analysis (for two different quench protocols), investigate nonaffine displacement field under external strain, linear response to an $\ensuremath{\delta}$ force, and low-frequency harmonic eigenmodes their density distribution. Qualitatively similar behavior...

Using large scale molecular dynamics simulations we investigate the properties of nonaffine displacement field induced by macroscopic uniaxial deformation amorphous silica, a strong glass according to Angell's classification. We demonstrate existence length $\ensuremath{\xi}$ characterizing correlations this (corresponding volume about 1000 atoms), and compare its structure one observed in standard fragile model glass. The ``boson-peak'' anomaly density states can be traced back both cases...

The vibrational properties of model amorphous materials are studied by combining complete analysis the vibration modes, dynamical structure factor, and energy diffusivity with exact diagonalization matrix kernel polynomial method, which allows a study very large system sizes. Different that differ only bending rigidity interactions in Stillinger-Weber modelization used to describe silicon. local can thus be as control parameter, tune sound velocity together bonds directionality. It is shown...

We study the effect of long-range elastic interactions in dynamical behavior an chain driven quasi-statically a quenched random pinning potential and strong limit. This is generic situation occuring solid friction, crack propagation, wetting front motion, ... Tuning exponent algebraic decay interaction with distance shown to give rise three regimes: Mean-Field (MF) regime, Laplacian (L) regime intermediate where critical exponents interpolate continuously between MF L limit cases. The...

The density of vibrational states in amorphous materials is known to present an unusual shape related as "boson peak", and responsible for the very specific thermal behaviour these systems. In this letter, we show how modes a model Lennard-Jones glass are affected by mechanical load. Far from instability, can be described at low frequency weak scattering acoustic modes. Close plastic some them localize. We "localized" modes, juste before directly spatial organization rearrangements. A...

In this paper we perform quasistatic shear simulations of model amorphous silicon bulk samples with Stillinger-Weber-type potentials. Local plastic rearrangements identified based on local energy variations are fitted through their displacement fields collections Eshelby spherical inclusions, allowing determination transformation strain tensors. The latter then used to quantitatively reproduce atomistic stress-strain curves, in terms both and pressure components. We demonstrate that our...

Shale swelling can cause a series of problems during the exploitation shale gas. However, because complex fabric shale, thorough understanding has not been gained. In this work, an experimental multiscale approach is employed to characterize properties sample from Sichuan basin China. Wetting/drying tests are performed by environmental scanning electron microscopy (ESEM), and deformation material measured analyzing ESEM micrographs using digital image correlation (DIC) techniques....

Phonon diffraction and interference patterns are observed at the atomic scale, using molecular dynamics simulations in systems containing crystalline silicon nanometric obstacles, such as voids or amorphous inclusions. The due to these nano-architectured of same scale phonon wavelengths similar ones predicted by simple Fresnel–Kirchhoff integral. few differences between two approaches attributed nature interface anisotropy silicon. Based on wave description phonons, findings can provide...

The linear response of two-dimensional amorphous elastic bodies to an external delta force is determined in analogy with recent experiments on granular aggregates. For the generated forces, stress, and displacement fields, we find strong relative fluctuations order 1 close source, which, however, average out readily classical predictions isotropic continuum elasticity. stress decay (essentially) exponentially distance from source. Only beyond a surprisingly large distance,...

The mechanism of plastic flow in amorphous solids involves nucleation-controlled shear transformations, triggered under stress from fertile sites. However, the origin these sites is still a matter debate. In this paper, we show that connection between local activity and coordination defects systems depends on nature interatomic interactions. particular, directionality bonds, as quantified by three-body term Stillinger-Weber-like interactions, affects not only role defects, but also size...

Mechanical spectroscopy, i.e. cyclic deformations at varying frequencies, is used theoretically and numerically to measure dissipation in model glasses. From a normal mode analysis, we show that the high-frequency THz regime where harmonic, quality factor (or loss angle) can be expressed analytically. This expression validated through non-equilibrium molecular dynamics simulations applied of amorphous silica (SiO$_2$). Dissipation shown arise from non-affine relaxations triggered by strain...

In amorphous solids, a non-negligible part of thermal conductivity results from phonon scattering on the structural disorder. The conversion acoustic energy into is often measured by dynamical dtructure factor (DSF) thanks to inelastic neutron or x-ray scattering. DSF used quantify dispersion relation phonons, together with their damping. However, connection structure attenuation wave packets in glasses still matter debate. We focus here analysis wave-packet propagation numerical models...

We investigate the low-frequency end of vibrational spectrum in small (nanometric) disordered systems. Using numerical simulation and exact diagonalization for simple two-dimensional models, we show that continuum elasticity, applied to these systems, actually breaks down below a length scale typically 30 50 molecular sizes. This is likely related one which generally invoked explain peculiar properties glassy