In this paper, the ageing behaviour of suspensions laponite with varying salt concentration is investigated using rheological tools. It observed that accompanied by an increase in complex viscosity. The creep experiments performed at various ages show damped oscillations strain. characteristic time scale oscillations, retardation time, shows a prominent decrease increasing age system. However, dependence weakens concentration, which known to change microstructure system from glass like gel...

Soft, disordered, micro-structured materials are ubiquitous in nature and industry, different from ordinary fluids or solids, with unusual, interesting static flow properties. The transition fluid to solid -at the so-called jamming density- features a multitude of complex mechanisms, but there is no unified theoretical framework that explains them all. In this study, simple yet quantitative predictive model presented, which allows for variable, changing density, encompassing memory...

Physical experiments can characterize the elastic response of granular materials in terms macroscopic state variables, namely volume (packing) fraction and stress, while microstructure is not accessible thus neglected. Here, by means numerical simulations, we analyze dense, frictionless assemblies with final goal to relate moduli fabric state, i.e., microstructural averaged contact network features as number density anisotropy. The particle samples are first isotropically compressed then...

Ballasted tracks are the commonly used railway track systems with constant demands for reducing maintenance cost and improved performance. Elastic layers increasingly improving ballasted tracks. In order to better understand effects of elastic layers, physical understanding at ballast particle level is crucial. Here, discrete element method (DEM) investigate - under sleeper pad ( USP ) sleeper/ballast interface mat UBM ballast/bottom on micro-mechanical behavior ballast. DEM model, Conical...

Stress- and structure-anisotropy (bulk) responses to various deformation modes are studied for dense packings of linearly elastic, frictionless, polydisperse spheres in the (periodic) triaxial box element test configuration. The major goal is formulate a guideline procedure how calibrate theoretical model with discrete particle simulations selected tests then predict another calibrated (parameters).Only simplest possible particulate material chosen as basic reference example all future...

The dynamic wheel-rail contact forces resulting from the interaction between vehicle and track are responsible for local settlement. If these settlements vary along track, geometric irregularities develop further amplifying loading of caused by track. In this work, an efficient vehicle-track (VTI) model is presented predicting long-term evolution vertical settlement during operation. VTI has two interacting components – describes dynamics 8th a car. considers elastic rail on discrete...

This paper presents a whole system model framework that enables holistic prediction of accumulated track damage in railway turnouts. A modular approach allows for insight into the interaction different mechanisms such as rail profile change due to plastic deformation and wear well settlement. The methodology focuses on two most critical areas turnout terms damage: switch crossing panels. It is shown at beginning service life running surface rails these significantly deformation, which turn...

We present numerical evidence for an additional discontinuous transition, upon compression, inside the jammed regime asymmetric bidisperse granular packing. This transition line separates states with networks of predominantly large particles from formed by both and small particles, is indicated a discontinuity in number contributing to network. The emerges curves jamming transitions terminates end point where vanishes. starting at size ratio around $\ensuremath{\delta}=0.22$ grows longer...

The challenge of dealing with cohesive powders during storage, handling and transport are widely known in the process pharmaceutical industries. Simulations discrete element method (DEM) provide further insight into local microstructure bulk materials. In this work, DEM approach is presented to investigate flow behavior granular systems subjected different modes deformations. When uniaxial compression applied frictionless, polydisperse spheres above jamming (transition from fluid-like state...

Understanding the mechanical stiffness of closely packed, dense granular systems is interest in many fields, such as soil mechanics, material science and physics. The main difficulty arises due to discreteness disorder materials at microscopic scale which requires a multi-scale approach. Discrete Element Method (DEM) powerful tool inspect influence contact properties its individual constituents on bulk behavior assemblies. In this study, isotropic deformation mode polydisperse packings...

We present 3D DEM simulations of bidisperse granular packings to investigate their jamming densities, $\phi_J$, and dimensionless bulk moduli, $K$, as a function the size ratio, $\delta$, concentration small particles, $X_{\mathrm S}$. determine partial total moduli for each packing report transition diagram, i.e., density or volume fraction marking both first second transitions system. At large enough difference, e.g., $\delta \le 0.22$, $X^{*}_{\mathrm S}$ divides diagram with most...

Physical experiments can characterize the elastic response of granular materials in terms macroscopic state-variables, namely volume (packing) fraction and stress, while microstructure is not accessible thus neglected. Here, by means numerical simulations, we analyze dense, frictionless, assemblies with final goal to relate moduli fabric state, i.e., micro-structural averaged contact network features as number density anisotropy. The particle samples are first isotropically compressed later...

We analyze the behavior of a frictionless dense granular packing sheared at constant volume. Goal is to predict evolution effective moduli along loading path. Because structural anisotropy that develops in system, volumetric and deviatoric stresses strains are cross coupled via four distinct quantities, classical bulk shear two moduli. Here, by means numerical simulation, we apply small perturbations various equilibrium states previously experienced different pure investigate effect...

(III): [4 alpha,6 beta(E)]-(+-)-6-(2-[2-(4-Fluoro-3-methylphenyl)- 4,4,6,6-tetramethyl-1-cyclohexen-1-yl]ethenyl)-4-hydroxytetrahy dro pyran-2-one (RG-12561) dichloromethane solvate, 2C24H31FO3.CH2-Cl2, Mr = 857.94, triclinic, Pl, a 11.7413 (5), b 13.0279 c 16.2332 (9) A, alpha 99.456 (4), beta 94.217 gamma 101.893 (4) degrees, V 2381.9 A3, Z 4 [four molecules of (III)+two solvent per unit cell], Dx 1.195 g cm-3, Cu K alpha, lambda 1.54178 mu 16.69 cm-1, F(000) 912, T 293 K, final R 0.053,...