Model Establishment of a Co-Based Metal Matrix with Additives of WC and Ni by Discrete Element Method

A metal matrix is an indispensable component of metal-bonded diamond tools. The composition design of a metal matrix involves a number of experiments, making costly in terms of time, labor, and expense. The discrete element method (DEM) is a potential way to relieve these costs. The aim of this work is to demonstrate a methodology for establishing and calibrating metal matrix’s DEM model. A Co-based metal matrix with WC and Ni additives (CoX–WC–Ni) was used, in which the Co-based metal was Co–Cu–Sn metal (CoX). The skeletal substances in the metal matrix were treated as particles in the model, and the bonding substances were represented by the parallel bond between particles. To describe the elasticity of the metal matrix, a contact bond was also loaded between particles. A step-by-step calibration procedure with experimental tests of three-point bending and compression was proposed to calibrate all microcosmic parameters involved during the establishment of DEM models: first for the CoX matrix, then for the CoX–WC matrix and CoX–Ni matrix, and finally for the CoX–WC–Ni matrix. The CoX–WC–Ni DEM model was validated by the transverse rupture strength (TRS) of two new compositions and the results indicated that the model exhibited a satisfactory prediction ability with an error rate of less than 10%.

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Discrete element method to model cracking for two layer systems

TAPPI Journal ◽

10.32964/tj18.2.101 ◽

2019 ◽

Vol 18 (2) ◽

pp. 101-108

Author(s):

Daniel Varney ◽

Douglas Bousfield

Keyword(s):

Discrete Element Method ◽

Flexural Modulus ◽

Single Layer ◽

Discrete Element ◽

Flexural Stress ◽

Layer System ◽

Three Point Bending ◽

Moving Force ◽

Coating Layers ◽

Element Method

Cracking at the fold is a serious issue for many grades of coated paper and coated board. Some recent work has suggested methods to minimize this problem by using two or more coating layers of different properties. A discrete element method (DEM) has been used to model deformation events for single layer coating systems such as in-plain and out-of-plain tension, three-point bending, and a novel moving force picking simulation, but nothing has been reported related to multiple coating layers. In this paper, a DEM model has been expanded to predict the three-point bending response of a two-layer system. The main factors evaluated include the use of different binder systems in each layer and the ratio of the bottom and top layer weights. As in the past, the properties of the binder and the binder concentration are input parameters. The model can predict crack formation that is a function of these two sets of factors. In addition, the model can predict the flexural modulus, the maximum flexural stress, and the strain-at-failure. The predictions are qualitatively compared with experimental results reported in the literature.

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

Agriculture ◽

10.3390/agriculture11050425 ◽

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.

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Discrete element method approach to modelling VPP dampers

MATEC Web of Conferences ◽

10.1051/matecconf/201815702014 ◽

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.

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

AgriEngineering ◽

10.3390/agriengineering3040056 ◽

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.

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

Transactions of the ASABE ◽

10.13031/trans.13995 ◽

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.

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A Surrogate Discrete Element Method for Terramechanics Simulation of Granular Locomotion

Volume 6: 11th International Conference on Multibody Systems, Nonlinear Dynamics, and Control ◽

10.1115/detc2015-46104 ◽

2015 ◽

Cited By ~ 2

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.

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Parametric Study on Strength Characteristics of Two-Dimensional Ice Beam Using Discrete Element Method

Applied Sciences ◽

10.3390/app11188409 ◽

2021 ◽

Vol 11 (18) ◽

pp. 8409

Author(s):

Seongjin Song ◽

Wooyoung Jeon ◽

Sunho Park

Keyword(s):

Bond Strength ◽

Discrete Element Method ◽

Strength Criterion ◽

Discrete Element ◽

Strength Characteristics ◽

Two Dimensional ◽

Three Point Bending ◽

Local Parameters ◽

Compressive Tests ◽

Element Method

Strength characteristics of a two-dimensional ice beam were studied using a discrete element method (DEM). The DEM solver was implemented by the open-source discrete element method libraries. Three-point bending and uniaxial compressive tests of the ice beam were simulated. The ice beam consisted of an assembly of disk-shaped particles with a particular thickness. The connection of the ice particles was modelled using a cuboid element, which represents a bond. If the stress acting on the bond exceeded the bond strength criterion, the bond started to break, explaining the cracking of the ice beam. To find out the effect of the local parameters of the contact and bond models on the ice fracture, we performed numerical simulations for various bond Young‘s modulus of the particles, the bond strength, and the relative particle size ratio.

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Numerical Simulation of Granite Sawing by Discrete Element Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.16-19.1283 ◽

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.

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Torque Analysis of a Gyratory Crusher with the Discrete Element Method

Minerals ◽

10.3390/min11080878 ◽

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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A 2D Electromechanical Model of Human Atrial Tissue Using the Discrete Element Method

BioMed Research International ◽

10.1155/2015/854953 ◽

2015 ◽

Vol 2015 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

Paul Brocklehurst ◽

Ismail Adeniran ◽

Dongmin Yang ◽

Yong Sheng ◽

Henggui Zhang ◽

...

Keyword(s):

Discrete Element Method ◽

Electromechanical Coupling ◽

Cardiac Tissue ◽

Viscoelastic Body ◽

Discrete Element ◽

Tissue Cell ◽

Electromechanical Model ◽

Atrial Tissue ◽

Dem Model ◽

Element Method

Cardiac tissue is a syncytium of coupled cells with pronounced intrinsic discrete nature. Previous models of cardiac electromechanics often ignore such discrete properties and treat cardiac tissue as a continuous medium, which has fundamental limitations. In the present study, we introduce a 2D electromechanical model for human atrial tissue based on the discrete element method (DEM). In the model, single-cell dynamics are governed by strongly coupling the electrophysiological model of Courtemanche et al. to the myofilament model of Rice et al. with two-way feedbacks. Each cell is treated as a viscoelastic body, which is physically represented by a clump of nine particles. Cell aggregations are arranged so that the anisotropic nature of cardiac tissue due to fibre orientations can be modelled. Each cell is electrically coupled to neighbouring cells, allowing excitation waves to propagate through the tissue. Cell-to-cell mechanical interactions are modelled using a linear contact bond model in DEM. By coupling cardiac electrophysiology with mechanics via the intracellular Ca2+concentration, the DEM model successfully simulates the conduction of cardiac electrical waves and the tissue’s corresponding mechanical contractions. The developed DEM model is numerically stable and provides a powerful method for studying the electromechanical coupling problem in the heart.

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