Discrete element method (DEM) numerical modeling of double-twisted hexagonal mesh

2008 ◽  
Vol 45 (8) ◽  
pp. 1104-1117 ◽  
Author(s):  
David Bertrand ◽  
François Nicot ◽  
Philippe Gotteland ◽  
Stéphane Lambert
Keyword(s):  
Discrete Element Method ◽  
Experimental Tests ◽  
Discrete Element ◽  
Numerical Approach ◽  
Point Of View ◽  
Wire Mesh ◽  
Model Parameters ◽  
Elastoplastic Behavior ◽  
Mesh Model ◽  
Element Method

Double-twisted hexagonal mesh is used in several fields of civil engineering (gabion structures, retaining nets against rockfalls, etc.). This paper presents an approach based on the discrete element method (DEM) to model this specific mechanical system. Constitutive modeling in finite strains is proposed to take into account the elastoplastic behavior with hardening of the metallic wire mesh. Model parameters are calibrated from a macroscopic point of view by comparing simulations to experimental tensile strength tests performed at the wire-mesh sheet scale. Additional experimental tests, with different mesh sizes and wire diameters, are conducted, yielding valuable data to validate this numerical approach. Lastly, the modeling capabilities are investigated. The simulation of a rockfall-protection structure subjected to an impact loading is presented and the results are discussed from an engineering point of view.

Calibration of discrete-element-method model parameters of bulk wheat for storage

2020 ◽  
Vol 200 ◽  
pp. 298-314
Author(s):  
J. Horabik ◽  
J. Wiącek ◽  
P. Parafiniuk ◽  
M. Bańda ◽  
R. Kobyłka ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Model Parameters ◽  
Method Model ◽  
Element Method

scholarly journals ВПЛИВ КОНСТРУКЦІЙ ВІДЦЕНТРОВИХ ЗМІШУВАЧІВ НА ЇХ ЗГЛАДЖУВАЛЬНУ ЗДАТНІСТЬ

2020 ◽  
Vol 142 (1) ◽  
pp. 11-18
Author(s):  
В. В. Стаценко ◽  
О. П. Бурмістенков ◽  
Т. Я. Біла
Keyword(s):  
Discrete Element Method ◽  
Residence Time ◽  
Mixing Time ◽  
Discrete Element ◽  
Point Of View ◽  
Design Parameters ◽  
Discrete Elements ◽  
Bulk Materials ◽  
Design Features ◽  
Element Method

Studying the influence of continuous centrifugal mixers design features on their smoothing ability. The methods used are discrete elements, mathematical modeling and regression analysis. The paper considers five continuous centrifugal mixers designs with conical and parabolic rotors. The mixers design features are determined, allowing to change their smoothing ability. Mathematical models of the bulk materials particles movement inside each mixer have been developed based on the discrete element method. The considered mixers reaction to a step change of the key component amount is investigated. The transients parameters are calculated and the particles average residence time in the mixer is determined. It is established that the introduction of turbulizers in the mixers design increases the particles kinetic energy, which leads to a decrease in their residence time in the mixer. Moreover, the absence of a turbulizer leads to a decrease in the mixing intensity. It was also found that the most effective way to increase the mixer smoothing ability is the introduction of additional rotors. In terms of the technological and design parameters combination, the use of mixers with a conical rotor and a turbulizer is the most effective from the point of view for increasing the smoothing ability. On the discrete element method basis, the bulk materials particles movement models in continuous centrifugal mixers of five designs have been developed. The influence of the mixers design features on their smoothing ability and average mixing time is determined. The results obtained allow us to select the appropriate mixer design according to the specified requirements for smoothing ability.

Numerical Simulation of Granite Sawing by Discrete Element Method

2009 ◽  
Vol 16-19 ◽  
pp. 1283-1288
Author(s):  
Yong Ye ◽  
Yuan Li ◽  
Xi Peng Xu
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Point Of View ◽  
Bending Tests ◽  
Three Point Bending ◽  
Deformation Stage ◽  
Initiation And Propagation ◽  
Discontinuous Deformation ◽  
Sawing Process ◽  
Element Method

Granite is a kind of typical discrete material, which experiences from continuous deformation stage, discontinuous deformation stage to fracture stage under sawing forces. Using discrete element method (DEM) to study the process of sawing granite will help us to understand the removal mechanism of granite from the microscopic point of view. In this paper, numerical uniaxial compression and three-point bending tests were conducted to determine the microscopic parameters of the granite specimen firstly, and then simulation was performed for sawing of the specimen. The sawing process, deformation characteristics of granite and the effect of initiation and propagation of cracks on fracture process of granite were investigated. The emphasis was laid on analyzing the variation of sawing forces under different sawing parameters. The simulation results agree well with that of experiments, indicating that DEM can reflect the external macroscopic change of granite by changing the internal microscopic structure. The conclusions in this study would be useful to the modeling of sawing processes and engineering applications.

Simulation of Energy Dissipation and Heat Transfers of a Braking System Using the Discrete Element Method: Role of Roughness and Granular Plateaus

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Viet-Dung Nguyen ◽  
Philippe Dufrénoy ◽  
Patrice Coorevits
Keyword(s):  
Energy Dissipation ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Heat Propagation ◽  
Point Of View ◽  
Disk Interface ◽  
Braking System ◽  
Interparticle Friction ◽  
Heat Transfers ◽  
Element Method

Abstract The objective of this study focuses on the energy dissipation by friction on the interface of a braking system and the effects of roughness and granular plateaus on heat propagation. Faced with the difficulty of defining velocity accommodation and thermal partition between the two bodies in contact (disk and pad, for example,), the authors model the third body (friction) layer with circular particles detached from the pad. From a numerical point of view, this paper proposes a strategy of storing mechanical calculations in steady-state and using it for successive thermal processing in discrete element method (DEM) code. Thus, the heat is generated due to interparticle friction and is dissipated in the disk/pad interface by conductance. Accordingly, this coupling micro–macro model aims to determine the temperature rise of the pad/disk interface and to identify the equivalent thermal resistance. In line with that, the authors provide discussions of these parameters compared to experimental/empirical data as reported in the literature review and limitations of the model.

scholarly journals Discrete Element Method Model Optimization of Cylindrical Pellet Size

Processes ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 101 ◽  
Author(s):  
Jiri Rozbroj ◽  
Jiri Zegzulka ◽  
Jan Necas ◽  
Lucie Jezerska
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Cylindrical Vessel ◽  
Model Parameters ◽  
Initial State ◽  
Pellet Size ◽  
Image Velocimetry ◽  
Kinematic Behaviour ◽  
The Coefficient Of Friction ◽  
Element Method

The DEM (Discrete Element Method) is one option for studying the kinematic behaviour of cylindrical pellets. The DEM experiments attempted to optimize the numerical model parameters that affected time and velocity as a cylindrical vessel emptied. This vessel was filled with cylindrical pellets. Optimization was accomplished by changing the coefficient of friction between particles and selecting the length accuracy grade of the sample cylindrical pellets. The initial state was a series of ten vessel-discharge experiments evaluated using PIV (Particle Image Velocimetry). The cylindrical pellet test samples were described according to their length in three accuracy grades. These cylindrical pellet length accuracy grades were subsequently used in the DEM simulations. The article discusses a comparison of the influence of the length accuracy grade of cylindrical pellets on optimal calibration of time and velocity when the cylindrical vessel is emptied. The accuracy grade of cylindrical pellet length in the DEM sample plays a significant role in relation to the complexity of a created simulation.

scholarly journals Measurement and Calibration of the Parameters for Discrete Element Method Modeling of Rapeseed

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 605
Author(s):  
Xiulong Cao ◽  
Zehua Li ◽  
Hongwei Li ◽  
Xicheng Wang ◽  
Xu Ma
Keyword(s):  
Discrete Element Method ◽  
Static Friction ◽  
Discrete Element ◽  
Rolling Friction ◽  
Particulate Material ◽  
Angle Of Repose ◽  
Model Parameters ◽  
Dem Simulation ◽  
Response Surface Optimization ◽  
Element Method

The discrete element method (DEM) for modeling the behavior of particulate material is highly dependent on the use of appropriate and accurate parameters. In this study, a seed metering DEM simulation was used to measure, calibrate, and verify the physical and interactional parameters of rapeseed. The coefficients of restitution and static friction between rapeseeds and three common materials (aluminum alloy, acrylic, and high-density polyethylene) were measured using free drop and sliding ramp tests, respectively. The angle of repose was determined using a hollow cylinder experiment, which was duplicated using a DEM simulation, to examine the effects of static and rolling friction coefficients on the angle of repose. Response surface optimization was performed to determine the optimized model parameters using a Box–Behnken design test. A metering device was made with three materials, and rapeseed seeding was simulated at different working speeds to verify the calibrated parameters. The validation results showed that the relative errors between the seed metering model and experiments for the single qualified seeding, missed seeding, and multiple seeding rates were −0.15%, 3.29%, and 5.37%, respectively. The results suggest that the determined physical and interactional parameters of rapeseed can be used as references for future DEM simulations.

scholarly journals Modeling of High-Density Compaction of Pharmaceutical Tablets Using Multi-Contact Discrete Element Method

Pharmaceutics ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2194
Author(s):  
Kostas Giannis ◽  
Carsten Schilde ◽  
Jan Henrik Finke ◽  
Arno Kwade
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Model Parameters ◽  
Pharmaceutical Tablets ◽  
Particle Level ◽  
Scale Calibration ◽  
Pharmaceutical Materials ◽  
Scale Particle ◽  
Uniaxial Compaction ◽  
Element Method

The purpose of this work is to simulate the powder compaction of pharmaceutical materials at the microscopic scale in order to better understand the interplay of mechanical forces between particles, and to predict their compression profiles by controlling the microstructure. For this task, the new framework of multi-contact discrete element method (MC-DEM) was applied. In contrast to the conventional discrete element method (DEM), MC-DEM interactions between multiple contacts on the same particle are now explicitly taken into account. A new adhesive elastic-plastic multi-contact model invoking neighboring contact interaction was introduced and implemented. The uniaxial compaction of two microcrystalline cellulose grades (Avicel® PH 200 (FMC BioPolymer, Philadelphia, PA, USA) and Pharmacel® 102 (DFE Pharma, Nörten-Hardenberg, Germany) subjected to high confining conditions was studied. The objectives of these simulations were: (1) to investigate the micromechanical behavior; (2) to predict the macroscopic behavior; and (3) to develop a methodology for the calibration of the model parameters needed for the MC-DEM simulations. A two-stage calibration strategy was followed: first, the model parameters were directly measured at the micro-scale (particle level) and second, a meso-scale calibration was established between MC-DEM parameters and compression profiles of the pharmaceutical powders. The new MC-DEM framework could capture the main compressibility characteristics of pharmaceutical materials and could successfully provide predictions on compression profiles at high relative densities.

A Numerical Method to Predict Packing Density of Aggregates in Concrete

2011 ◽  
Vol 337 ◽  
pp. 313-316 ◽  
Author(s):  
Mohammad Reisi ◽  
Davood Mostofi Nejad
Keyword(s):  
Computer Simulation ◽  
Discrete Element Method ◽  
Numerical Method ◽  
Efficient Method ◽  
Packing Density ◽  
Experimental Tests ◽  
Discrete Element ◽  
Element Method

It is nowadays very clear that the single most important parameter influencing the performance of concrete is the packing density of the aggregates. Among aggregate characteristics, grading of aggregates has the most significant effect on packing density (PD) of aggregates. In the current sstudy, packing density of five aggregates were measured by experimental tests and computer simulation base on discrete element method (DEM). Obtained results show that the performed computer simulation is very efficient method to predict packing density and optimization grading of aggregates.

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