Simulation of Coal Mechanical Characteristics with Discrete Element Method

2013 ◽  
Vol 671-674 ◽  
pp. 117-121
Author(s):  
Song Yong Liu ◽  
Hong Xiang Jiang ◽  
Kui Dong Gao
Keyword(s):  
Discrete Element Method ◽  
Mechanical Characteristics ◽  
Discrete Element ◽  
Particle Flow Code ◽  
Experimental Result ◽  
Uniaxial Compression Test ◽  
Micro Particles ◽  
Bond Model ◽  
Dem Model ◽  
Element Method

Base on the parallel-bond model in PFC2D(Particle Flow Code in two Dimension) used to describe the contact between coal micro-particles, DEM(Discrete Element Method) model of coal has been established, so that the coal uniaxial compression test could be investigated. By comparing the simulation result and experimental result, it is clear that DEM is suitable to simulate the mechanical characteristics and failure mode of coal. The effects of micro-parameters on the constitutive behaviors of coal simulation sample are discussed, they can provide basis for designing DEM model of other analogous coals with differenet mechanical characteristics. The microparameters of coal DEM model obtained in simulation test could be a guilding role for further developing the applicability of the DEM in coal mining, crushing and some other aspects.

scholarly journals Applications of Discrete Element Method in the Research of Agricultural Machinery: A Review

Agriculture ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 425
Author(s):  
Hongbo Zhao ◽  
Yuxiang Huang ◽  
Zhengdao Liu ◽  
Wenzheng Liu ◽  
Zhiqi Zheng
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Agricultural Machinery ◽  
Design And Optimization ◽  
Design Of Agricultural Machinery ◽  
Agricultural Materials ◽  
Operational Processes ◽  
Dem Model ◽  
Agricultural Machines ◽  
Element Method

As a promising and convenient numerical calculation approach, the discrete element method (DEM) has been increasingly adopted in the research of agricultural machinery. DEM is capable of monitoring and recording the dynamic and mechanical behavior of agricultural materials in the operational process of agricultural machinery, from both a macro-perspective and micro-perspective; which has been a tremendous help for the design and optimization of agricultural machines and their components. This paper reviewed the application research status of DEM in two aspects: First is the DEM model establishment of common agricultural materials such as soil, crop seed, and straw, etc. The other is the simulation of typical operational processes of agricultural machines or their components, such as rotary tillage, subsoiling, soil compaction, furrow opening, seed and fertilizer metering, crop harvesting, and so on. Finally, we evaluate the development prospects of the application of research on the DEM in agricultural machinery, and look forward to promoting its application in the field of the optimization and design of agricultural machinery.

scholarly journals Discrete element method approach to modelling VPP dampers

2018 ◽  
Vol 157 ◽  
pp. 02014
Author(s):  
Pawel Chodkiewicz ◽  
Jakub Lengiewicz ◽  
Robert Zalewski
Keyword(s):  
Discrete Element Method ◽  
Granular Medium ◽  
Discrete Element ◽  
Modeling And Analysis ◽  
Novel Approach ◽  
Particle Dampers ◽  
Pressure Boundary Conditions ◽  
Dem Model ◽  
Method Approach ◽  
Element Method

In this paper, we present a novel approach to modeling and analysis of Vacuum Packed Particle dampers (VPP dampers) with the use of Discrete Element Method (DEM). VPP dampers are composed of loose granular medium encapsulated in a hermetic envelope, with controlled pressure inside the envelope. By changing the level of underpressure inside the envelope, one can control mechanical properties of the system. The main novelty of the DEM model proposed in this paper is the method to treat special (pressure) boundary conditions at the envelope. The model has been implemented within the open-source Yade DEM software. Preliminary results are presented and discussed in the paper. The qualitative agreement with experimental results has been achieved.

scholarly journals Calibration of the Discrete Element Method Parameters in Living Juvenile Manila Clam (Ruditapes philippinarum) and Seeding Verification

2021 ◽  
Vol 3 (4) ◽  
pp. 894-906
Author(s):  
Hangqi Li ◽  
Guochen Zhang ◽  
Xiuchen Li ◽  
Hanbing Zhang ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Discrete Element Method ◽  
Static Friction ◽  
Discrete Element ◽  
Rolling Friction ◽  
Manila Clam ◽  
Average Error ◽  
Verification Test ◽  
Dem Model ◽  
Element Method

The Manila Clam is an important economic shellfish in China’s seafood industry. In order to improve the design of juvenile Manila Clam seeding equipment, a juvenile clam discrete element method (DEM) particle shape was established, which is based on 3D scanning and EDEM software. The DEM contact parameters of clam-stainless steel, and clam-acrylic were calibrated by combining direct measurements and test simulations (slope sliding and dropping). Then, clam DEM simulation and realistic seeding tests were carried out on a seeding wheel at different rotational speeds. The accuracy of the calibrated clam DEM model was evaluated in a clam seeding verification test by comparing the average error of the variation coefficient between the realistic and simulated seeding tests. The results showed that: (a) the static friction coefficients of clam-acrylic and clam-stainless steel were 0.31 and 0.23, respectively; (b) the restitution coefficients of clam-clam, clam-acrylic, and clam-stainless steel were 0.32, 0.48, and 0.32, respectively. Furthermore, the results of the static repose angle from response surface tests showed that when the contact wall was acrylic, the coefficient rolling friction and static friction of clam-clam were 0.17 and 1.12, respectively, and the coefficient rolling friction of clam-acrylic was 0.20. When the contact wall was formed of stainless steel, the coefficient rolling friction and static friction of clam-clam were 0.33 and 1.25, respectively, and the coefficient rolling friction of clam-stainless steel was 0.20. The results of the verification test showed that the average error between the realistic and simulated value was <5.00%. Following up from these results, the clam DEM model was applied in a clam seeding simulation.

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.

Nonlinear Dynamic Analysis of Space Frame Structures by Discrete Element Method

2014 ◽  
Vol 638-640 ◽  
pp. 1716-1719 ◽  
Author(s):  
Nian Qi ◽  
Ji Hong Ye
Keyword(s):  
Discrete Element Method ◽  
Dynamic Analysis ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Discrete Element ◽  
Internal Force ◽  
Frame Structures ◽  
Space Frame ◽  
Bond Model ◽  
Element Method

This document explores the possibility of the discrete element method (DEM) being applied in nonlinear dynamic analysis of space frame structures. The method models the analyzed object to be composed by finite particles and the Newton’s second law is applied to describe each particle’s motion. The parallel-bond model is adopted during the calculation of internal force and moment arising from the deformation. The procedure of analysis is vastly simple, accurate and versatile. Numerical examples are given to demonstrate the accuracy and applicability of this method in handling the large deflection and dynamic behaviour of space frame structures. Besides, the method does not need to form stiffness matrix or iterations, so it is more advantageous than traditional nonlinear finite 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.

A Surrogate Discrete Element Method for Terramechanics Simulation of Granular Locomotion

2015 ◽  
Author(s):  
William Smith ◽  
Huei Peng
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Vehicle Design ◽  
Simulation Accuracy ◽  
Semi Empirical ◽  
And Control ◽  
Drawbar Pull ◽  
Driving Torque ◽  
Dem Model ◽  
Element Method

Numerical modeling methods, such as the discrete element method (DEM), are an increasingly popular alternative to traditional semi-empirical terramechanics techniques. While DEM has many advantages, including the ability to model more complex running gear and terrain profiles, it has not reached widespread popularity due to its high computation costs. In this study a surrogate DEM model (S-DEM) was developed to maintain the simulation accuracy and capabilities of DEM with reduced computation costs. This marks one of the first surrogate models developed for DEM, and the first known model developed for terramechanics. By storing wheel-soil interaction forces and soil velocities extracted from constant-velocity DEM simulations, S-DEM can quickly perform new dynamic wheel locomotion simulations. Using both DEM and S-DEM, wheel locomotion simulations were performed on flat and rough terrain. S-DEM was found to reproduce drawbar pull and driving torque well in both cases, though wheel sinkage errors were significant at times. Computation costs were reduced by three orders of magnitude in comparison to DEM, bringing the benefits of DEM modeling to vehicle design and control. The techniques used to develop S-DEM may be applicable to other common DEM applications, such as soil drilling, excavating, and plowing.

Numerical Studies of Cutting Water Saturated Sand by Discrete Element Method

2012 ◽  
Vol 256-259 ◽  
pp. 306-310 ◽  
Author(s):  
Shao Hua Qin ◽  
Li Quan Xie ◽  
Guo Jun Hong ◽  
Jie Wang
Keyword(s):  
Discrete Element Method ◽  
Sandy Loam ◽  
Static Friction ◽  
Discrete Element ◽  
Particle Flow Code ◽  
Saturated Sand ◽  
Model Soil ◽  
Water Saturated ◽  
Cutting Model ◽  
Element Method

The discrete element method (DEM) has been recognized as an effective tool to simulate soil–tool interactions. In this study, a saturated sand cutting model is developed using a commercial DEM software, Particle Flow Code in Two Dimension (PFC 2D). In the model, soil are defined as particles with the basic PFC 2D model, full coupling with a deformable fluid. The mechanical interactions between particles and also between particles and the walls are modeled by sprints, dash-pots and friction sliders. The properties of the material and interactions (Poisson’s ratio, shear modulus and density, coefficients of restitution, rolling and static friction) relate to the particle properties and not to the bulk properties. Such quantitative and qualitative models are essential for improving the design, selection and use of water saturated sand cutting implements, in different field sand under different conditions. This paper describes a numerical experimental investigation of the failure characteristics of two-dimensional water saturated sand cutting. Comprehensive simulated tests were carried out on sandy loam using a box apparatus and two model plane blades of rake angles 30º, 60º and two angles of friction 32º,42º, respectively. Besides, there are two extreme densities of the sand, compacted and loose. These factors should provide a basis for the reliable prediction of the failure type.

scholarly journals A modified bond model for describing isotropic linear elastic material behaviour with the discrete element method

2021 ◽  
Author(s):  
Rahav Gowtham Venkateswaran ◽  
Ursula Kowalsky ◽  
Dieter Dinkler
Keyword(s):  
Discrete Element Method ◽  
Elastic Material ◽  
Poisson’S Ratio ◽  
Strain Energy ◽  
Discrete Element ◽  
Poisson's Ratio ◽  
Linear Elastic Material ◽  
Linear Elastic ◽  
Bond Model ◽  
Element Method

AbstractRecently, the discrete element method is increasingly being used for describing the behaviour of isotropic linear elastic materials. However, the common bond models employed to describe the interaction between particles restrict the range of Poisson’s ratio that can be represented. In this paper, to overcome the restriction, a modified bond model that includes the coupling of shear strain energy of neighbouring bonds is proposed. The coupling is described by a multi-bond term that enables the model to distinguish between shear deformations and rigid-body rotations. The positive definiteness of the strain energy function of the modified bond model is verified. To validate the model, uniaxial tension, pure shear and pure bending tests are performed. Comparison of the particle displacements with continuum mechanics solution demonstrates the ability of the model to describe the behaviour of isotropic linear elastic material for values of Poisson’s ratio in the range $$0 \le \nu < 0.5$$ 0 ≤ ν < 0.5 .

scholarly journals Torque Analysis of a Gyratory Crusher with the Discrete Element Method

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 878
Author(s):  
Manuel Moncada ◽  
Patricio Toledo ◽  
Fernando Betancourt ◽  
Cristian G. Rodríguez
Keyword(s):  
Discrete Element Method ◽  
Discrete Element ◽  
Copper Industry ◽  
Nominal Data ◽  
Operational Conditions ◽  
Torque Analysis ◽  
Radial Forces ◽  
Dem Model ◽  
Selection Of ◽  
Element Method

Comminution by gyratory crusher is the first stage in the size reduction operation in mineral processing. In the copper industry, these machines are widely utilized, and their reliability has become a relevant aspect. In order to optimize the design and to improve the availability of gyratory crushers, it is necessary to calculate their power and torque accurately. The discrete element method (DEM) has been commonly used in several mining applications and is a powerful tool to predict the necessary power required in the operation of mining machines. In this paper, a DEM model was applied to a copper mining gyratory crusher to perform a comprehensive analysis of the loads in the mantle, the crushing torque, and crushing power. A novel polar representation of the radial forces is proposed that may help designers, engineers, and operators to recognize the distribution of force loads on the mantle in an easier and intuitive way. Simulations with different operational conditions are presented and validated through a comparison with nominal data. A calculation procedure for the crushing power of crushers is presented, and recommendations for the selection of the minimum resolved particle size are given.

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