Role of micro‐heterogeneities on fabric, stress, and elastic anisotropy in granular media

2011 ◽  
Author(s):  
Ratnanabha Sain ◽  
Tapan Mukerji ◽  
Gary Mavko
Keyword(s):  
Granular Media ◽  
Elastic Anisotropy

Role of contact couples and couple stress in the behaviour of granular media

1998 ◽  
Vol 08 (PR8) ◽  
pp. Pr8-87-Pr8-94
Author(s):  
F. Dedecker ◽  
Ph. Dubujet ◽  
B. Cambou
Keyword(s):  
Couple Stress ◽  
Granular Media

Tunnel excavation in granular media: the role of force chains

2021 ◽  
Vol 23 (4) ◽  
Author(s):  
Raj Kumar Pal ◽  
Robert Buraque de Macedo ◽  
José E Andrade
Keyword(s):  
Granular Media ◽  
Force Chains ◽  
Tunnel Excavation

scholarly journals Hydrostatic Parameters and Domain Effects in Novel 2-2 Composites Based on PZN-0.12PT Single Crystals

2011 ◽  
Vol 2011 ◽  
pp. 1-10
Author(s):  
Vitaly Yu. Topolov ◽  
Sergei V. Glushanin ◽  
Alexander A. Panich
Keyword(s):  
Electromechanical Coupling ◽  
Volume Fraction ◽  
Elastic Anisotropy ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Single Domain ◽  
Absolute Minimum ◽  
Component Orientation ◽  
Record Value

A novel 0.88Pb(Zn1/3Nb2/3)O3-0.12PbTiO3 crystal/polymer composite with 2-2 connectivity is studied at variable orientations of spontaneous polarisation vector of the crystal component. Orientation and volume-fraction dependences of the hydrostatic piezoelectric coefficients dh*, eh*, and gh* and hydrostatic electromechanical coupling factor kh* are related to the important role of the piezoelectric and elastic anisotropy of single-domain layers of the 2-2 composite. The record value of |eh∗|≈77 C/m2 near the absolute-minimum point and the correlation between the hydrostatic (eh*) and piezoelectric (e3j*) coefficients and between the hydrostatic (gh*) and piezoelectric (g3j*) coefficients are first established. This discovery is of value for hydrostatic and piezotechnical applications. The hydrostatic performance of the composite based on the single-domain 0.88Pb(Zn1/3Nb2/3)O3-0.12PbTiO3 crystal is compared to the performance of the 2–2 composites based on either the same polydomain crystal or the related single-domain crystal.

scholarly journals Continuum Modeling of Granular Media

2014 ◽  
Vol 66 (5) ◽  
Author(s):  
J. D. Goddard
Keyword(s):  
Granular Flow ◽  
Granular Media ◽  
Evolution Equations ◽  
Particle Migration ◽  
Internal Variables ◽  
Continuum Modeling ◽  
Material Instability ◽  
Rapid Flow ◽  
Internal Balance

This is a survey of the interesting phenomenology and the prominent regimes of granular flow, followed by a unified mathematical synthesis of continuum modeling. The unification is achieved by means of “parametric” viscoelasticity and hypoplasticity based on elastic and inelastic potentials. Fully nonlinear, anisotropic viscoelastoplastic models are achieved by expressing potentials as functions of the joint isotropic invariants of kinematic and structural tensors. These take on the role of evolutionary parameters or “internal variables,” whose evolution equations are derived from the internal balance of generalized forces. The resulting continuum models encompass most of the mechanical constitutive equations currently employed for granular media. Moreover, these models are readily modified to include Cosserat and other multipolar effects. Several outstanding questions are identified as to the contribution of parameter evolution to dissipation; the distinction between quasielastic and inelastic models of material instability; and the role of multipolar effects in material instability, dense rapid flow, and particle migration phenomena.

scholarly journals Фактор предпочтения базисной краевой дислокационной петли в цирконии. Численный анализ

2020 ◽  
Vol 62 (12) ◽  
pp. 2087
Author(s):  
А.В. Бабич ◽  
В.Ф. Клепиков ◽  
П.Н. Остапчук
Keyword(s):  
Elastic Anisotropy ◽  
Elastic Field ◽  
Elastic Interaction ◽  
Growth Theory ◽  
Hexagonal Crystal ◽  
Bias Factor ◽  
Area Of Influence ◽  
Hexagonal Crystals ◽  
Toroidal Geometry

Recent numerical calculations of the diffusion coefficients of radiation point defects in hexagonal crystals have made it clear that the main assumption of the radiation growth theory of zirconium (DAD - diffusional anisotropy difference) does not allow one to describe the radiation growth correctly. Thus, the elastic ideology (EID - elastic interaction difference), based on the concept of the flow bias factor, remains relevant. Therefore, the bias factor for the basic edge loop of zirconium in a toroidal reservoir was calculated numerically (using the finite difference method), taking into account the elastic anisotropy of the hexagonal crystal. The toroidal geometry of the reservoir makes it possible to calculate the flows for a loop of any size and without any correction of the elastic field in its area of influence. The dependences of the loop bias factor on its radius and nature are obtained for various sink densities. The essential role of the form of the boundary condition on the outer surface of the reservoir is shown. The prospects for further research in the construction of the theory of the radiation growth of zirconium based on the elastic ideology are discussed.

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