A critical analysis of the conditions elastic stability crystal structures different symmetry as restrictions imposed on their constants c ij has been carried out. It is shown that all crystals, except for cubic ones, are described by polynomials from second to sixth powers . Necessary and sufficient crystals presented explicitly. Keywords: Elastic stability, Symmetry, constants, Stability cond...

2014 The elastic constants, magnetic susceptibility, refractive index and density are reported for p,p’-diheptylazobenzene. The behaviour of the elastic constants of this non polar compound is very similar to that of related polar compounds. The anisotropy of both the static and the highfrequency permittivity is proportional to the anisotropy of the susceptibility, as observed earlier for the h...

Quasicrystals can carry, in addition to the classical phonon displacement field, a phason displacement field, which requires a generalized theory of elasticity. In this paper, the third-order strain invariants (including phason strain) of icosahedral quasicrystals are determined. They are connected with 20 independent third-order elastic constants. By means of non-linear elasticity, phason stra...

Recently it was shown that a wave profile which minimises total energy, elastic plus hydrodynamic, subject to the vorticity distribution being prescribed, gives rise to a steady hydroelastic wave. Using this formulation, the existence of non-trivial minimisers leading to such waves was established for certain non-zero values of the elastic constants. Here we show that when these constants are z...

— Recent progress in approaches to determine the elastic constants of solids starting from the microscopic particle interactions is reviewed. On the theoretical side, density functional theory approaches are discussed and compared to more classical ones using the actual pair potentials. On the experimental side, video microscopy has been introduced to measure the elastic constants in colloidal ...

A tight-binding model is fit to first-principles calculations for copper that include structures distorted according to elastic constants and highsymmetry phonon modes. With the resulting model the first-principlesbased phonon dispersion and the free energy are calculated in the quasiharmonic approximation. The resulting thermal expansion, the temperatureand volume-dependence of the elastic con...

2014 Surface torques exerted by a nematic liquid crystal on a solid plate are investigated. Three different geometries are considered. The torques are generated by applying a uniform magnetic field to the nematic sample and are measured by a torsion pendulum. The elastic constants of the nematic Liquid Crystal and the anchoring energy at the interface can be obtained by this kind of measurement...

A theoretical study of the structural, elastic, and mechanical properties of B19 TiAl intermetallic compound with orthorhombic structure has been carried out by using ab initio density functional theory calculations based on the projector augmented wave and the generalized gradient approximation. The optimized structure parameters are found to be in agreement with the available experimental dat...

An automated computational strategy is devised for the ab initio determination of the full fourth-rank piezo-optic tensor of crystals belonging to any space group of symmetry. Elastic stiffness and compliance constants are obtained as numerical first derivatives of analytical energy gradients with respect to the strain and photo-elastic constants as numerical derivatives of analytical dielectri...

The technique of resonant ultrasound spectroscopy (RUS) was used to measure the second-order elastic constants of hydrated human dentin. Specimens were placed between two transducers, and the resonant frequencies of vibration were measured between 0.5 and 1.4 MHz. The elastic constants determined from the measured resonant frequencies in hydrated dentin exhibited slight hexagonal anisotropy, wi...