scholarly journals High compressibility caused by particle breakage: a DEM investigation

2021 ◽  
Vol 249 ◽  
pp. 07011
Author(s):  
Marta Stasiak ◽  
Vincent Richefeu ◽  
Gaël Combe ◽  
Jad Zghondi ◽  
Gilles Armand
Keyword(s):  
Constitutive Model ◽  
Discrete Element Method ◽  
Prediction Model ◽  
Experimental Studies ◽  
Discrete Element ◽  
Double Porosity ◽  
Engineering Practice ◽  
Cylindrical Particles ◽  
Oedometer Tests ◽  
Mechanical Phenomena

This paper summarises the numerical and experimental studies of brittle, hollow, cylindrical particles, called shells. It addresses the influence of shell properties both at the particle and assembly scales. Extreme compressibility has been recorded in the oedometer tests. Due to the large internal porosity of the shell, the breakage phenomena lead to highly compressive deformations with a significant stress dissipation. Using the Discrete Element Method (DEM), we have investigated in depth the micro-mechanical phenomena governing this macroscopic response. By quantifying the breakage and separating the double-porosity of the material, the foundations of a future constitutive model have been established throughout a simple prediction model applicable to the engineering practice.

Numerical study of sheared mobile polydisperse sediment beds with a coupled lattice Boltzmann - discrete element method

2021 ◽  
Author(s):  
Christoph Rettinger ◽  
Sebastian Eibl ◽  
Ulrich Rüde ◽  
Bernhard Vowinckel
Keyword(s):  
Discrete Element Method ◽  
Lattice Boltzmann ◽  
Numerical Study ◽  
Experimental Studies ◽  
Discrete Element ◽  
Parallel Execution ◽  
Coupling Mechanism ◽  
Size Segregation ◽  
Minimum Diameter ◽  
Element Method

<p>With the increasing computational power of today's supercomputers, geometrically fully resolved simulations of particle-laden flows are becoming a viable alternative to laboratory experiments. Such simulations enable detailed investigations of transport phenomena in various multiphysics scenarios, such as the coupled interaction of sediment beds with a shearing fluid flow. There, the majority of available simulations as well as experimental studies focuses on setups of monodisperse particles. In reality, however, polydisperse configurations are much more common and feature unique effects like vertical size segregation.</p><p>In this talk, we will present numerical studies of mobile polydisperse sediment beds in a laminar shear flow, with a ratio of maximum to minimum diameter up to 10. The lattice Boltzmann method is applied to represent the fluid dynamics through and above the sediment bed efficiently. We model particle interactions by a discrete element method and explicitly account for lubrication forces. The fluid-particle coupling mechanism is based on the geometrically fully resolved momentum transfer between the fluid and the particulate phase. We will highlight algorithmic aspects and communication schemes essential for massively parallel execution.</p><p>Utilizing these capabilities allows us to achieve large-scale simulations with more than 26.000 densely-packed polydisperse particles interacting with the fluid. With this, we are able to reproduce effects like size segregation and to study the rheological behavior of such systems in great detail. We will evaluate and discuss the influence of polydispersity on these processes. These insights will be used to improve and extend existing macroscopic models.</p>

scholarly journals A local constitutive model for the discrete element method. Application to geomaterials and concrete

2015 ◽  
Vol 2 (2) ◽  
pp. 139-160 ◽  
Author(s):  
Eugenio Oñate ◽  
Francisco Zárate ◽  
Juan Miquel ◽  
Miquel Santasusana ◽  
Miguel Angel Celigueta ◽  
...  
Keyword(s):  
Constitutive Model ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Element Method

DEM study of the angle of repose and porosity distribution of cylindrical particles with different lengths

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Heng Zhou ◽  
Xu Tian ◽  
Xingyu Guo ◽  
Mingyin Kou ◽  
Shengli Wu ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Rolling Friction ◽  
Contour Line ◽  
Angle Of Repose ◽  
Cylindrical Particle ◽  
Porosity Distribution ◽  
Average Porosity ◽  
Cylindrical Particles

Abstract Effect of the length of cylindrical particle on repose angle and porosity of a pile was numerically studied using discrete element method. The variation of repose angle and porosity with coefficient of sliding and rolling friction were also discussed. The results shown that compared with sphere particle, the bottom size of cylindrical pile is smaller, while the height of cylinder pile is larger and the heap is steeper. With the increase of the length of cylinder, the contour line of the pile becomes steep, and the angle of repose increases. The repose angle shows a positive correlation with coefficient of sliding and rolling friction. The porosity increases with the increase of the length of cylinders. The trends of porosity are basically consist with that of repose angle, and with increase of friction coefficient, the average porosity increases.

Applicable Contact Force Models for the Discrete Element Method: The Single Particle Perspective

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
H. Kruggel-Emden ◽  
S. Wirtz ◽  
V. Scherer
Keyword(s):  
Discrete Element Method ◽  
Granular Materials ◽  
Experimental Studies ◽  
Spherical Shape ◽  
Discrete Element ◽  
Industrial Applications ◽  
Contact Forces ◽  
Experimental Investigations ◽  
Simulation Techniques ◽  
Element Method

Several processes in nature as well as many industrial applications involve static or dynamic granular materials. Granulates can adopt solid-, liquid-, or gaslike states and thereby reveal intriguing physical phenomena not observable in its versatility for any other form of matter. The frequent occurrence of phase transitions and the related characteristics thereby strongly affect their processing quality and economics. This situation demands for prediction methods for the behavior of granulates. In this context simulations provide a feasible alternative to experimental investigations. Several different simulation approaches are applicable to granular materials. The time-driven discrete element method turns out to be not only the most complex but also the most general simulation approach. Discrete element simulations have been used in a wide variety of scientific fields for more than 30 years. With the tremendous increase in available computer power, especially in the past years, the method is more and more developing to the state of the art simulation technique for granular materials not only in science but also in industrial applications. Several commercial software packages utilizing the time-driven discrete element method have emerged and are becoming more and more popular within the engineering community. Despite the long time of usage of the time-driven discrete element method, model advances derived and theoretical and experimental studies performed in the different branches of application lack harmonization. They thereby provide potential for improvements. Therefore, the scope of this paper is a review of methods and models for contact forces based on theoretical considerations and experimental data from literature. Particles considered are of spherical shape. Through model advances it is intended to contribute to a general enhancement of simulation techniques, which help improve products and the design of the related equipment.

scholarly journals Modelling of Rock Cutting with Asymmetrical Disc Tool Using Discrete-Element Method (DEM)

2021 ◽  
Author(s):  
Grzegorz Stopka
Keyword(s):  
Discrete Element Method ◽  
Simulation Model ◽  
Laboratory Tests ◽  
Experimental Studies ◽  
Deep Understanding ◽  
Discrete Element ◽  
Rock Cutting ◽  
Analytical Models ◽  
Mining Methods ◽  
Element Method

AbstractThe use of asymmetrical disc tools for the mining of hard and very hard rocks is a promising direction for developing mechanical mining methods. A significant obstacle in developing mining methods with the use of asymmetric disc tools is the lack of adequate computational methods. A deep understanding of rock–tool interaction can develop industrial applications of asymmetric disc tools significantly. The fundamental problem in designing work systems with asymmetric disc tools is the lack of adequate analytical models to identify tool loads during the mining process. One reasonable approach is to use computer simulation. The purpose of the research was to develop a simulation model of rock cutting using an asymmetrical disc tool and then evaluate the developed model. In the article, the Discrete-Element Method (DEM) in LS-Dyna was adopted to simulate rock cutting with asymmetrical disc tools. Numerical tests were conducted by pushing the disc into a rock sample at a given distance from the sample edge until the material was detached entirely. Two types of rock samples were used in the simulation tests: concrete and sandstone. The independent variables in the study were the disc diameter and the cut spacing. To validate the simulation model, analogous laboratory tests were carried out. The article presents a comparison of the results of simulation and laboratory tests. The given comparison showed good accordance LS-Dyna model with the experimental studies. The proposed test results can be input data for developing simulation models on a larger scale. Thus, it will be possible to consider the complex kinematics of the dynamics of the rock-mining process with disc tools using the DEM simulation.

Attenuation of pressure dips underneath piles of spherocylinders

Soft Matter ◽  
2018 ◽  
Vol 14 (21) ◽  
pp. 4404-4410 ◽  
Author(s):  
Haiyang Zhao ◽  
Xizhong An ◽  
Dazhao Gou ◽  
Bo Zhao ◽  
Runyu Yang
Keyword(s):  
Discrete Element Method ◽  
Particle Shape ◽  
Discrete Element ◽  
Cylindrical Particles ◽  
Element Method

The discrete element method (DEM) was used to simulate the piling of rod-like (elongated sphero-cylindrical) particles, mainly focusing on the effect of particle shape on the structural and force properties of the piles.

Prediction model for non-inversion soil tillage implemented on discrete element method

2014 ◽  
Vol 106 ◽  
pp. 120-127 ◽  
Author(s):  
Elvis López Bravo ◽  
Engelbert Tijskens ◽  
Miguel Herrera Suárez ◽  
Omar Gonzalez Cueto ◽  
Herman Ramon
Keyword(s):  
Discrete Element Method ◽  
Prediction Model ◽  
Discrete Element ◽  
Soil Tillage ◽  
Element Method
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