scholarly journals Certain Discrete Element Methods in Problems of Fracture Mechanics

10.14311/374 ◽  
2002 ◽  
Vol 42 (4) ◽  
Author(s):  
P. P. Procházka ◽  
M. G. Kugblenu
Keyword(s):  
Material Properties ◽  
Granular Media ◽  
Dynamic Equilibrium ◽  
Discrete Element ◽  
Particle Flow ◽  
Particle Flow Code ◽  
Classical Particle ◽  
Numerical Experience ◽  
Discrete Element Methods ◽  
Element Method

In this paper two discrete element methods (DEM) are discussed. The free hexagon element method is considered a powerful discrete element method, which is broadly used in mechanics of granular media. It substitutes the methods for solving continuum problems. The great disadvantage of classical DEM, such as the particle flow code (material properties are characterized by spring stiffness), is that they have to be fed with material properties provided from laboratory tests (Young's modulus, Poisson's ratio, etc.). The problem consists in the fact that the material properties of continuum methods (FEM, BEM) are not mutually consistent with DEM. This is why we utilize the principal idea of DEM, but cover the continuum by hexagonal elastic, or elastic-plastic, elements. In order to complete the study, another one DEM is discussed. The second method starts with the classical particle flow code (PFC - which uses dynamic equilibrium), but applies static equilibrium. The second method is called the static particle flow code (SPFC). The numerical experience and comparison numerical with experimental results from scaled models are discussed in forthcoming paper by both authors.

scholarly journals Application of Discrete Element Methods to the Problem of Rock Bumps

10.14311/378 ◽  
2002 ◽  
Vol 42 (4) ◽  
Author(s):  
P. P. Procházka ◽  
M. G. Kugblenu
Keyword(s):  
Discrete Element Method ◽  
Granular Media ◽  
Dynamic Equilibrium ◽  
Discrete Element ◽  
Particle Flow ◽  
Particle Flow Code ◽  
Classical Particle ◽  
Discrete Element Methods ◽  
Scaled Models ◽  
Element Method

This paper is a continuation of a previous paper by the authors. Applications of two discrete element methods (DEM) to several fields of geotechnics are discussed. The free hexagon element method is considered a powerful discrete element method, and is widely used in mechanics of granular media. It substitutes the methods for solving continuum problems. In order to complete the study, other discrete element methods are discussed. The second method starts with the classical particle flow code (PFC, which uses dynamic equilibrium), but we apply static equilibrium in our case. The second method is called the static particle flow code (SPFC). The numerical experiences and comparison with experimental results from scaled models are discussed.

scholarly journals Performance based simulation of pervious concrete using discrete element method

2020 ◽  
Vol 72 (08) ◽  
pp. 693-701
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Pervious Concrete ◽  
Particle Flow ◽  
Particle Flow Code ◽  
The Finite Element Method ◽  
Ordinary Concrete ◽  
Paste Content ◽  
Highly Porous ◽  
Element Method

Pervious concrete is a special type of concrete that differs from ordinary concrete by its highly porous nature, which is why this type of discrete material can not be modelled using the Finite Element Method (FEM). Behaviour of pervious concrete samples with different aggregate sizes and void ratios is simulated in the paper, using the Particle Flow Code (PFC) software, which is based on the discrete element method (DEM). The PFC software is used to simulate various experimental results obtained on high paste content pervious concrete samples.

Simulation of Uniaxial Compression for Flexible Fibers of Wheat Straw Using the Discrete Element Method

2021 ◽  
Vol 64 (6) ◽  
pp. 2025-2034
Author(s):  
Matthew W Schramm ◽  
Mehari Z. Tekeste ◽  
Brian L Steward
Keyword(s):  
Discrete Element Method ◽  
Wheat Straw ◽  
Young’S Modulus ◽  
Uniaxial Compression ◽  
Material Properties ◽  
Young's Modulus ◽  
Discrete Element ◽  
Flexible Fibers ◽  
Dem Model ◽  
Element Method

HighlightsSimulation of uniaxial compression was performed with flexible fibers modeled in DEM.Bond-specific DEM parameters were found to be sensitive in uniaxial compression.A calibration technique that is not plunger-dependent is shown and validated.Abstract. To accurately simulate a discrete element method (DEM) model, the material properties must be calibrated to reproduce bulk material behavior. In this study, a method was developed to calibrate DEM parameters for bulk fibrous materials using uniaxial compression. Wheat straw was cut to 100.2 mm lengths. A 227 mm diameter cylindrical container was loosely filled with the cut straw. The material was pre-compressed to 1 kPa. A plunger (50, 150, or 225 mm diameter) was then lowered onto the compressed straw at a rate of 15 mm s-1. This experimental procedure was simulated using a DEM model for different material properties to generate a simulated design of experiment (DOE). The simulated plunger had a travel rate of 40 mm s-1. The contact Young’s modulus, bond Young’s modulus, and particle-to-particle friction DEM parameters were found to be statistically significant in the prediction of normal forces on the plunger in the uniaxial compression test. The DEM calibration procedure was used to approximate the mean laboratory results of wheat straw compression with root mean square (RMS) percent errors of 3.77%, 3.02%, and 13.90% for the 50, 150, and 225 mm plungers, respectively. Keywords: Calibration, DEM, DOE, Flexible DEM particle, Uniaxial compression, Wheat straw.

Numerical Simulation of Particle Flow for High Velocity Compaction Based on Discrete Element Method

2010 ◽  
Author(s):  
Wang Shuang ◽  
Zheng Zhoushun ◽  
Zheng Shan ◽  
Jane W. Z. Lu ◽  
Andrew Y. T. Leung ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Discrete Element Method ◽  
High Velocity ◽  
Discrete Element ◽  
Particle Flow ◽  
High Velocity Compaction ◽  
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.

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