scholarly journals Calibration Strategy to Determine the Interaction Properties of Fertilizer Particles Using Two Laboratory Tests and DEM

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 592
Author(s):  
Sugirbay Adilet ◽  
Jian Zhao ◽  
Nukeshev Sayakhat ◽  
Jun Chen ◽  
Zagainov Nikolay ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Laboratory Tests ◽  
Agricultural Research ◽  
Numerical Technique ◽  
Interaction Parameters ◽  
Nonlinear Relationship ◽  
Granular Assemblies ◽  
Real Behavior ◽  
Transient Forces ◽  
Central Composite

Investigating the interactions of granular fertilizers with various types of equipment is an essential part of agricultural research. A numerical technique simulating the mechanical behavior of granular assemblies has the advantage of data trackings, such as the trajectories, velocities, and transient forces of the particles at any stage of the test. The interaction parameters were calibrated to simulate responses of granular fertilizers in EDEM, a discrete element method (DEM) software. Without a proper calibration of the interaction parameters between the granular fertilizers and various materials, the simulations may not represent the real behavior of the granular fertilizers. Therefore, in this study, a strategy is presented to identify and select a set of DEM input parameters of granular fertilizers using the central composite design (CCD) to establish the nonlinear relationship between the dynamic macroscopic granular fertilizer properties and the DEM parameters. The determined interaction properties can be used to simulate granular fertilizers in EDEM.

scholarly journals Transition zone in Bearing Capacity Problem from Plasticity Method, Discrete Element Method and Laboratory tests

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Yungming Cheng
Keyword(s):  
Discrete Element Method ◽  
Bearing Capacity ◽  
Transition Zone ◽  
Laboratory Tests ◽  
Friction Angle ◽  
Discrete Element ◽  
Element Approach ◽  
Plastic Stage ◽  
Elastic Stage ◽  
The Continuum

<p>In this paper, the classical bearing capacity problem and the logspiral transition zone are re-considered from a continuum plasticity approach as well as discrete element approach. In the discrete element approach, the bearing capacity problem is considered from the elastic stage, plastic stage to the final rupture stage. It is found that there are noticeable differences in the failure mechanism between the continuum and discontinuum analyses, and the well-known logspiral transition zone is also not apparent in both the discrete element approach, plasticity approach as well as the laboratory tests. With the increase in the friction angle of soil, the transition zone is becoming more like a wedge zone than a logspiral zone as found from the present study. </p>

New Knowledge in the Field of Reduction of Shear Stress in the Foundation Structures of Concrete or Masonry Structures

2014 ◽  
Vol 1082 ◽  
pp. 224-229
Author(s):  
Martina Smirakova
Keyword(s):  
Laboratory Tests ◽  
Mechanical Load ◽  
Thermal Sensitivity ◽  
Masonry Structures ◽  
Horizontal Deformation ◽  
Friction Forces ◽  
Sliding Joint ◽  
Real Behavior ◽  
Sliding Joints ◽  
Foundation Structure

This paper deals with application of sliding joint into foundation structures which can be very helpful in case that the foundation structure is exposed to effect of relative horizontal deformation. These deformations can be created direct in the structure from the effect of creep or shrinkage of concrete, from the effect of pre-stressing of foundation structure or they can arise in the subsoil as a consequence of undermining. Sliding joints are often created from asphalt belts which help to increase of friction forces in the foundation bottom. Due to fact that today ́s market gives a lot of new modern materials, the laboratory tests are carried out to verify their behavior at the Faculty of Civil Engineering VŠB Technical University of Ostrava (Czech Republic). The basic principle of these tests is to simulate real behavior sliding joint in foundation structure and great attention is also focused on thermal sensitivity of majority of used materials. Thermal sensitivity at the action of mechanical load relates closely with their rheological properties. Rheology is the science about deformation of substances in the dependence on time and it helps to describe difficult materials using simpler rheological materials models. A right created rheological model of asphalt belt could be used to prediction of behavior of sliding joint with regard to time of loading and ambient temperature. The knowledge of change of asphalt belt behavior consequently to temperature change could be used in the future to design of this type sliding joint where the temperature will be not only monitored but also managed in the dependence on necessity of increasing or decreasing of shear resistance. Partial results from laboratory tests as well as current conclusion will be presented in this paper.

Closed-End Cylindrical Shell Under Line Load Along a Generator

1980 ◽  
Vol 102 (1) ◽  
pp. 90-97 ◽  
Author(s):  
U. S. Chawla
Keyword(s):  
Cylindrical Shell ◽  
Finite Difference ◽  
Discrete Element Method ◽  
Computer Program ◽  
Circular Cylindrical Shell ◽  
Numerical Technique ◽  
Elastic Analysis ◽  
Line Load ◽  
Shell Plate ◽  
Free Body

This paper presents a numerical technique for elastic analysis of a thin circular cylindrical shell with end plates under uniform line load along a generator. This technique is based upon the discrete element method. An accurate set of the governing differential equations due to Vlasov is used. The derivatives with respect to the circumferential coordinate are replaced by finite difference relationships. The end plate is analyzed as a free body under unit concentrated edge loads and the resulting coefficients are used to satisfy continuity conditions at the shell-plate junction. A computer program to implement this technique is developed and results are compared with those published in the literature. A number of new results are presented.

scholarly journals Crack nucleation in solid materials under external load - simulations with the Discrete Element Method

2018 ◽  
Vol 165 ◽  
pp. 22019
Author(s):  
Piotr Klejment ◽  
Wojciech Dębski
Keyword(s):  
Boundary Conditions ◽  
Discrete Element Method ◽  
Crack Nucleation ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Solid Material ◽  
Discrete Element ◽  
Biological Tissues ◽  
External Forces ◽  
Element Method

Numerical analysis of cracking processes require an appropriate numerical technique. Classical engineering approach to the problem has its roots in the continuum mechanics and is based mainly on the Finite Element Method. This technique allows simulations of both elastic and large deformation processes, so it is very popular in the engineering applications. However, a final effect of cracking - fragmentation of an object at hand can hardly be described by this approach in a numerically efficient way since it requires a solution of a problem of nontrivial evolving in time boundary conditions. We focused our attention on the Discrete Element Method (DEM), which by definition implies “molecular” construction of the matter. The basic idea behind DEM is to represent an investigated body as an assemblage of discrete particles interacting with each other. Breaking interaction bonds between particles induced by external forces imeditelly implies creation/evolution of boundary conditions. In this study we used the DEM approach to simulate cracking process in the three dimensional solid material under external tension. The used numerical model, although higly simplified, can be used to describe behaviour of such materials like thin films, biological tissues, metal coatings, to name a few.

scholarly journals Application of the Discrete Element Method for Manufacturing Process Simulation in the Pharmaceutical Industry

Pharmaceutics ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 414 ◽  
Author(s):  
Yeom ◽  
Ha ◽  
Kim ◽  
Jeong ◽  
Hwang ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Pharmaceutical Industry ◽  
Discrete Element Method ◽  
Process Simulation ◽  
Discrete Element ◽  
Pharmaceutical Manufacturing ◽  
Interaction Parameters ◽  
Dem Simulation ◽  
Process Understanding ◽  
Contact Models

Process simulation using mathematical modeling tools is becoming more common in the pharmaceutical industry. A mechanistic model is a mathematical modeling tool that can enhance process understanding, reduce experimentation cost and improve product quality. A commonly used mechanistic modeling approach for powder is the discrete element method (DEM). Most pharmaceutical materials have powder or granular material. Therefore, DEM might be widely applied in the pharmaceutical industry. This review focused on the basic elements of DEM and its implementations in pharmaceutical manufacturing simulation. Contact models and input parameters are essential elements in DEM simulation. Contact models computed contact forces acting on the particle-particle and particle-geometry interactions. Input parameters were divided into two types—material properties and interaction parameters. Various calibration methods were presented to define the interaction parameters of pharmaceutical materials. Several applications of DEM simulation in pharmaceutical manufacturing processes, such as milling, blending, granulation and coating, were categorized and summarized. Based on this review, DEM simulation might provide a systematic process understanding and process control to ensure the quality of a drug product.

scholarly journals Modelling of Rock Cutting with Asymmetrical Disc Tool Using Discrete-Element Method (DEM)

2021 ◽  
Author(s):  
Grzegorz Stopka
Keyword(s):  
Discrete Element Method ◽  
Simulation Model ◽  
Laboratory Tests ◽  
Experimental Studies ◽  
Deep Understanding ◽  
Discrete Element ◽  
Rock Cutting ◽  
Analytical Models ◽  
Mining Methods ◽  
Element Method

AbstractThe use of asymmetrical disc tools for the mining of hard and very hard rocks is a promising direction for developing mechanical mining methods. A significant obstacle in developing mining methods with the use of asymmetric disc tools is the lack of adequate computational methods. A deep understanding of rock–tool interaction can develop industrial applications of asymmetric disc tools significantly. The fundamental problem in designing work systems with asymmetric disc tools is the lack of adequate analytical models to identify tool loads during the mining process. One reasonable approach is to use computer simulation. The purpose of the research was to develop a simulation model of rock cutting using an asymmetrical disc tool and then evaluate the developed model. In the article, the Discrete-Element Method (DEM) in LS-Dyna was adopted to simulate rock cutting with asymmetrical disc tools. Numerical tests were conducted by pushing the disc into a rock sample at a given distance from the sample edge until the material was detached entirely. Two types of rock samples were used in the simulation tests: concrete and sandstone. The independent variables in the study were the disc diameter and the cut spacing. To validate the simulation model, analogous laboratory tests were carried out. The article presents a comparison of the results of simulation and laboratory tests. The given comparison showed good accordance LS-Dyna model with the experimental studies. The proposed test results can be input data for developing simulation models on a larger scale. Thus, it will be possible to consider the complex kinematics of the dynamics of the rock-mining process with disc tools using the DEM simulation.

scholarly journals Polarization of contact forces in multi-contact systems

2010 ◽  
pp. 77-88
Author(s):  
Serge Dumont ◽  
Jerôme Fortin ◽  
Youssef Ouafik
Keyword(s):  
Discrete Element Method ◽  
Continuum Mechanics ◽  
Laboratory Tests ◽  
Phenomenological Approach ◽  
Contact Forces ◽  
Solid Materials ◽  
Multi Scale ◽  
Basic Physics ◽  
Polarization Phenomena ◽  
The Moment

The aim of this study is to identify the homogenized laws modeling the overall behaviour of multi-contact systems. At the moment, these systems are generally analyzed either by continuum mechanics or micro-mechanics and a multi-scale approach. These approaches differ from the phenomenological approach traditionally used for modeling the behavior of solid materials which is based on mathematical formulations developed in the framework of thermodynamics, whose constants are determined from results of laboratory tests. The lack of basic physics in these formulations leads to mathematical models that are often complex and difficult to identify. The multi-scale approach appears well suited to address these difficulties. This study aims at quantification using the Discrete Element method (Jean, 1999; Fortin et al., 2005) polarization phenomena of contact forces.

scholarly journals Mesoscale inertial transition in granular materials

2021 ◽  
Vol 249 ◽  
pp. 10004
Author(s):  
Adriane Clerc ◽  
Antoine Wautier ◽  
Stéphane Bonelli ◽  
François Nicot
Keyword(s):  
Kinetic Energy ◽  
Discrete Element Method ◽  
Granular Material ◽  
Granular Materials ◽  
Failure Mode ◽  
Discrete Element ◽  
Loading Path ◽  
Failure Patterns ◽  
Granular Assemblies ◽  
Failure State

Granular assemblies can experience complex failure patterns along a given loading path, with a distribution of ephemeral inertial events marked by local outbursts in kinetic energy. However, investigating such mechanisms appears to be necessary to understand how a certain failure mode develops in a granular material. Using a discrete element method, this study highlights several microstructure reorganizations before the specimen reaches a proper failure state. Meso structures have proven to be efficient to understand the elementary mechanisms responsible for these outbursts in kinetic energy. Strain–like and stress-like quantities are thus defined at a mesoscale and they are used to characterize the nucleation and propagation of these local microstructural events.

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

Simulation of Heat Transfer in Moving Granular Material by the Discrete Element Method With Special Emphasis on Inner Particle Heat Transfer

2009 ◽  
Author(s):  
S. Rickelt ◽  
H. Kruggel-Emden ◽  
S. Wirtz ◽  
V. Scherer
Keyword(s):  
Heat Transfer ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Temperature Model ◽  
Contact Heat ◽  
Radial Temperature ◽  
Dem Simulations ◽  
Contact Heat Transfer ◽  
Granular Assemblies ◽  
Element Method

Physical processes involving static or dynamic granular assemblies are best modeled on the particle scale by Discrete Element Methods (DEM) rather than continuum approaches. Due to the high computational effort of DEM simulations, present studies assume the inner particle temperature to be spatially uniform and neglect the inner particle heat transfer. For this reason the Radial Temperature Model was introduced [1, 2] It assumes radial temperature distributions within the particles and is based on an analytical solution of the heat conduction equation in a spherical particle. The scope of this paper is to present the further development of the Radial Temperature Model that allows to simulate granular systems of particles of different sizes and materials, enabling the use of DEM in various applications. The contact heat transfer is modeled making additional material-specific data unnecessary. It is shown that a very good accuracy for the contact heat transfer between different spherical particles is achieved for binary contacts. DEM simulations were performed using the Radial Temperature Model and uniform particle temperatures, respectively. The results demonstrate that the Radial Temperature Model that has been developed and incorporated in the Discrete Element Method allows for an improved calculation of the transient thermal behavior of granular assemblies even for large numbers of particles.

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