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.

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

Study on Initial States of Steel Balls in Mill by Discrete Element Method

2012 ◽  
Vol 546-547 ◽  
pp. 120-124
Author(s):  
Ping Zhou ◽  
Jing Hong Du ◽  
Xi Xiang Duan
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Three Dimensions ◽  
Particle Flow Code ◽  
Filling Rate ◽  
Initial State ◽  
State Models ◽  
Steel Balls ◽  
Small Steel ◽  
Element Method

Based on Discrete Element Method(DEM), initial state models of steel balls were establisheded by Particle Flow Code in three Dimensions (PFC 3D), the initial void rate of steel balls at different filling rate were calculated. The results showed that at the same filling rate, the initial void rate of steel balls decreased as steel ball’s diameter decreased. The initial void rate of steel balls with one diameter and grading steel balls both increased gradully as ball filling rate increased, but the initial void rate of grading steel balls were smaller than that of steel balls with one diameter. The Stratification phenomenon will occur after steel balls in grading scheme reached to the initial equilibrium sates, that is, Large steel balls moved near the mill’s center, but small steel balls moved away from the mill’s center and close to the cylinder of mill, which is benifical to improve grinding effeciency.

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.

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.

Application of micro computed tomography for adjustment of model parameters for discrete element method

2018 ◽  
Vol 135 ◽  
pp. 121-128 ◽  
Author(s):  
Maksym Dosta ◽  
Ulrich Bröckel ◽  
Laurent Gilson ◽  
Sergiy Kozhar ◽  
Günter K. Auernhammer ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Model Parameters ◽  
Micro Computed Tomography ◽  
Element Method

scholarly journals Identification of numerical model parameters of tunnel lining in non-cohesive soil

2018 ◽  
Vol 67 (4) ◽  
pp. 41-58
Author(s):  
Paweł Szklennik
Keyword(s):  
Numerical Model ◽  
Discrete Element Method ◽  
Laboratory Tests ◽  
Cohesive Soil ◽  
Discrete Element ◽  
Tunnel Lining ◽  
Model Parameters ◽  
Soil Medium ◽  
Numeric Model ◽  
Element Method

The paper discusses identification of numeric model parameters of tunnel lining in a soil medium according to the discrete element method. An author’s program based on the discrete element method was used. Laboratory tests were conducted to determine the computer model parameters defining the lining and the soil medium. The numerical model was calibrated by comparing the lining deformations occurring in the laboratory test and in the numeric simulation. Tunnel lining displacement during laboratory tests was determined using digital photography. Keywords: civil engineering, discrete element method, cylindrical tunnel lining

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