scholarly journals A unified approach for static and dynamic fracture failure in solids and granular materials by a particle method

2015 ◽  
Vol 9 (34) ◽  
Author(s):  
Roberto Brighenti ◽  
Andrea Carpinteri ◽  
Nicholas Corbari
Keyword(s):  
Granular Materials ◽  
Dynamic Fracture ◽  
Particle Method ◽  
Unified Approach ◽  
Fracture Failure

scholarly journals To the Development of the Phenomenology of Fast Shear Flows of Grain Materials

2021 ◽  
Vol 27 (4) ◽  
pp. 585-598
Author(s):  
V. N. Dolgunin ◽  
O. O. Ivanov ◽  
S. A. Akopyan
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Granular Materials ◽  
Granular Medium ◽  
Stress Generation ◽  
Shear Stresses ◽  
Plastic Shear ◽  
Unified Approach ◽  
Shear Deformations ◽  
Rate Gradient

Phenomenological approaches to describing the rheological behavior of granular materials under conditions of rapid and quasi-plastic shear deformations are considered. A unified approach to the phenomenological-logical description of the physical parameter, called the temperature of the granular medium, and the mechanisms of shear stress generation is proposed. A description is given of the mechanism for generating shear stresses under the action of a flow of pulses directed along the shear rate gradient and caused by transverse quasi-diffusion of particles. This mechanism is taken into account in the rheological model in addition to the traditional mechanism of generating kinetic shear stresses under the action of tangential shock pulses.

Discrete Element Method applied to the simulation of the stress state in granular materials

Soil Research ◽  
2019 ◽  
Vol 57 (1) ◽  
pp. 85
Author(s):  
Gabriela Carolina Martínez Morillo ◽  
Alex Alves Bandeira
Keyword(s):  
Discrete Element Method ◽  
Granular Materials ◽  
Soil Mechanics ◽  
Particle Method ◽  
Discrete Element ◽  
Computational Costs ◽  
Basic Physics ◽  
Force Displacement ◽  
Graphical Presentation ◽  
Element Method

This work examines the Discrete Element Method (DEM), also known as the particle method, for its application in soil mechanics, specifically to calculate the tension acting on granular materials without cohesion. First, theoretical aspects of soil mechanics and the physical properties of some types of granular materials are presented, and the material properties are used afterwards in numerical examples. Following this, the DEM formulation is described, corresponding to the force and movement equations acting on each particle. For that, Newton’s second law, the force–displacement law, Hertz’s contact law, and some concepts from particle mechanics are defined. The integration over time process and the numerical solution algorithm presented by T.I. Zohdi are also described. Additionally, a new optimisation process for contact detection is described, one which significantly diminishes computational costs and therefore analysis time. Finally, some basic physics examples necessary for the formulation validation and application in soil mechanics are presented. The results obtained with the software developed in this research are then compared with soil mechanics results, which are simulated using the GeoStudio software. The GiD program was utilised for graphical presentation of the results.

Compression and shear-wave velocities in discrete particle simulations of quartz granular packings: Improved Hertz-Mindlin contact model

Geophysics ◽  
2011 ◽  
Vol 76 (5) ◽  
pp. E165-E174 ◽  
Author(s):  
Carlos Santos ◽  
Vanessa Urdaneta ◽  
Xavier García ◽  
Ernesto Medina
Keyword(s):  
Granular Materials ◽  
Particle Method ◽  
Contact Model ◽  
Discrete Particle ◽  
Unconsolidated Sands ◽  
Tangential Stiffness ◽  
Shear Wave Velocities ◽  
Effective Medium Theories ◽  
Particle Simulations ◽  
Discrete Particle Method

The Hertz-Mindlin (HM) contact model has been a cornerstone for the development of several effective medium theories (EMTs) aimed at describing the mesoscopic and macroscopic mechanical behavior of granular materials like unconsolidated sands. In addition, this model is at the core of most of the discrete particle method designs used to numerically solve for the responses of these heterogeneous materials to external perturbations, like acoustic and stress-strain experiments. However, this model has shown shortcomings in the description of the shear response characterization of granular materials, partly due to the non-affine motions experienced by the grains. We have developed a correction of the model based on a detailed calibration of our acoustic numerical results with previous empirical data. Using a microscopic approach to the grain-grain contact surfaces, the nature of the corrections found appear to be related to the shear resistant asperities and the smaller scale of the grain-grain contact areas compared to the total area assumed by the HM model. An improved HM model characterized by a tangential stiffness weakening is based on these surface corrections. Using this observation an enhanced EMT theory emerges based not only on the tangential stiffness modification but also on the velocity-pressure dependence obtained during the calibration of our numerical model.

Dissipation in granular materials

1998 ◽  
Vol 77 (5) ◽  
pp. 1413-1425 ◽  
Author(s):  
Dietrich E.Wolf, Farhang Radjai, Sabine Dipp
Keyword(s):  
Granular Materials

Universal features of the microbranching instability in dynamic fracture

1998 ◽  
Vol 78 (2) ◽  
pp. 243-251
Author(s):  
Eran Sharon, Jay Fineberg
Keyword(s):  
Dynamic Fracture

A Unified Approach to Study the Thermal Dynamics in Multilongitudinal Mode Semiconductor Lasers

2001 ◽  
Vol 20 (2) ◽  
pp. 159-169 ◽  
Author(s):  
M. Ganesh Madhan ◽  
P. R. Vaya ◽  
N. Gunasekaran
Keyword(s):  
Semiconductor Lasers ◽  
Unified Approach ◽  
Thermal Dynamics
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