Fluctuations of the instantaneous local Lagrangian strain epsilon(ij)(r,t), measured with respect to a static "reference" lattice, are used to obtain accurate estimates of the elastic constants of model solids from atomistic computer simulations. The measured strains are systematically coarse-grained by averaging them within subsystems (of size L(b)) of a system (of total size L) in the canonic...

Microscopic expressions for the elastic constants of binary liquid crystalline mixtures composed of short rigid uniaxial molecules are derived in the thermodynamic limit at small distorsions and a small density. Uniaxial and biaxial nematic phases are considered. The expressions involve the one-particle distribution functions and the potential energy of two-body short-range interactions. The th...

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Résumé : In this paper, two methods were applied to determine the different elastics constants of the face centered cubic austenitic stainless steel Fe0.62Cr0.185Ni0.185. Firstly, the quantum mechanical simulation was applied based on the first principles calculations within the generalized gradient approximation (GGA) by using the efficient strain-stress method. Secondly an artificial neural n...

We have carried out a detailed study of the chemical bonding for two room-temperature stable platinum silicide phases, tetragonal a-Pt2Si and orthorhombic PtSi. An analysis of the valence electronic charge density reveals surprising evidence of covalent three-center bonds in both silicide phases, as well as two-dimensional metallic sheets in a-Pt2Si. These elements of the bonding are further an...

Hydroxyapatite (HA) whisker reinforced polyetheretherketone (PEEK) composites have been investigated as bioactive materials for load-bearing orthopedic implants with tailored mechanical properties governed by the volume fraction, morphology, and preferred orientation of the HA whisker reinforcements. Therefore, the objective of this study was to establish key structure-property relationships an...

INTRODUCTION Computational modelling in orthopaedic biomechanics often uses continuum homogenised finite element models of the bone which require accurate definitions of its elastic properties. In this study the variation of the orthotropic elastic constants of cortical bone from the female anterior femoral midshaft were evaulated. Micro-finite-element (μFE) analysis of bone samples from 27 fem...

We calculate both the micromechanical response and bulk elastic constants of composites of rods embedded in elastic media. We find two fixed points for Poisson's ratio with respect to rod density: there is an unstable fixed point for Poisson's ratio =1/2 (an incompressible system) and a stable fixed point for Poisson's ratio =1/4 (a compressible system). We also derive approximate expressions f...

An enhanced valence force field model for zinc-blende crystals is developed to provide a unified description of the isothermal static and dynamical lattice properties of gallium arsenide. The expression for the lattice energy includes a second-nearest-neighbor coplanar interaction term, the Coulomb interaction between partially charged ions, and anharmonicity corrections. General relations are ...

We have computed the elastic constants of nanostructured carbon films as obtained from classical molecular dynamics simulations of a cluster beam deposition process. The calculations show that the elastic constants of the deposited films are related to the average size of the clusters by a power law. This allows us to extrapolate the present theoretical data to the scale of the experimental res...