Computer Simulation on Centrifugal Barrel Surface Finishing Based on Discrete Element Method

2008 ◽  
Vol 53-54 ◽  
pp. 45-50
Author(s):  
C.H. Song ◽  
Shi Chun Yang ◽  
J.M. Wang ◽  
Y.Q. Zhang
Keyword(s):  
Discrete Element Method ◽  
Production Efficiency ◽  
Discrete Element ◽  
Contact Forces ◽  
Velocity Variation ◽  
Surface Finishing ◽  
Design Parameters ◽  
Abrasive Particles ◽  
Revolution Speed ◽  
Element Method

According to the motion features of abrasive particles and workpieces in centrifugal roller, considering the abrasive particles and workpieces as two kinds of ball particles with different materials and sizes, 3-Dimensional Discrete Element Method (DEM) was used to build the dynamics model of single abrasive particles and workpieces motion. Based on such model, in this paper, the influence of rotation-revolution ratio on medium movement was mainly analyzed. Supposing filling ratio as 20%, mixing ratio as 1.5:1 and revolution speed as 180r/min, the movement procedure of medium within centrifugal roller was respectively simulated under the different cases of rotation-revolution ratio as -0.13, -1 and -2, then the velocity variation diagram and the average contact forces diagram for abrasive particles or workpieces under different rotation-revolution ratio were obtained, the simulation results are basically coincident to the experimental results. Both results have proved that rotation-revolution ratio is the main parameter that changes medium motion law, which provides a very efficient way to further optimize design parameters and process parameters, as well as to improve production efficiency.

Dynamics Model Research of Centrifugal Barrel Surface Finishing Based on 3D Discrete Element Method

2009 ◽  
Vol 416 ◽  
pp. 127-132 ◽  
Author(s):  
Chun Hua Song ◽  
Shi Chun Yang
Keyword(s):  
Discrete Element Method ◽  
Process Parameters ◽  
Production Efficiency ◽  
Discrete Element ◽  
Surface Finishing ◽  
Design Parameters ◽  
Dynamics Model ◽  
Fill Ratio ◽  
Abrasive Particles ◽  
Element Method

Dynamics model on abrasive particles and workpieces during the centrifugal barrel surface finishing process was built by Discrete Element Method (DEM). The motion status of abrasive particles and workpieces was visually simulated and some important process parameters were numerically studied. The influence of fill ratio on finishing efficiency was analyzed, and finishing efficiency was the highest as the fill ratio is 65%. the simulation results are basically coincident to the experimental results. Both results have proved that filling ratio is the main parameter that changes medium motion laws, which provides an very efficient way to further optimize design parameters and process parameters, as well as to improve production efficiency.

Dynamic Simulation and Analysis of Centrifugal Barrel Surface Finishing Based on 3D Discrete Element Method

2009 ◽  
Vol 407-408 ◽  
pp. 432-435 ◽  
Author(s):  
Chun Hua Song ◽  
Shi Chun Yang
Keyword(s):  
Discrete Element Method ◽  
Process Parameters ◽  
Discrete Element ◽  
Transmission Ratio ◽  
Surface Finishing ◽  
Mechanism Analysis ◽  
Abrasive Particles ◽  
Planetary Transmission ◽  
Barrel Finishing ◽  
Element Method

Dynamics model on abrasive particles and workpieces during the centrifugal barrel surface finishing process was built by Discrete Element Method (DEM). The motion status of abrasive particles and workpieces was visually simulated and some important process parameters were numerically studied. The influence of planetary transmission ratio on finishing efficiency was analyzed, and finishing efficiency was the highest as the transmission ratio is -1. Finally, the conclusion was validated by experiments. Such economical and precise method could replace lots of finishing tests to optimize process parameters, which would provide theoretic basis for experimental research and efficient means for the finishing mechanism analysis of centrifugal barrel finishing.

scholarly journals A Numerical Study of Railway Ballast Subjected to Direct Shearing Using the Discrete Element Method

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Hongyi Zhao ◽  
Jing Chen
Keyword(s):  
Discrete Element Method ◽  
Mechanical Performance ◽  
Numerical Study ◽  
Discrete Element ◽  
Contact Forces ◽  
Angle Of Repose ◽  
Particle Rotation ◽  
Railway Ballast ◽  
Depth Analysis ◽  
Element Method

Railway ballast is a coarse granular material used to carry train loads and provide drainage for the rail tracks. This study presents numerical explorations of the mechanical performance of ballast aggregates subjected to direct shear tests. The discrete element method (DEM) was used to investigate the microscopic characteristics of ballast aggregates during shearing while considering contact distribution, particle rotation, and particle displacement. By testing the angle of repose of ballast aggregates, the parameters for the DEM contact model could be calibrated. Four specimens were prepared and then subjected to different normal pressures. The results show that the contact between ballast particles intensifies in terms of the amount and magnitude as the normal pressure increases. A Fourier analysis was applied to investigate the anisotropy of contact normal and the contact forces for ballast aggregates at different shearing phases. The rotational and translational movements of ballast particles were investigated, and this investigation revealed that particle rotation gradually increased as the shearing propagated. Four regions in the aggregates were identified according to the translational pattern of ballast particles. The results of this research provide an in-depth analysis of microscopic characteristics from a particulate scale.

scholarly journals ВПЛИВ КОНСТРУКЦІЙ ВІДЦЕНТРОВИХ ЗМІШУВАЧІВ НА ЇХ ЗГЛАДЖУВАЛЬНУ ЗДАТНІСТЬ

2020 ◽  
Vol 142 (1) ◽  
pp. 11-18
Author(s):  
В. В. Стаценко ◽  
О. П. Бурмістенков ◽  
Т. Я. Біла
Keyword(s):  
Discrete Element Method ◽  
Residence Time ◽  
Mixing Time ◽  
Discrete Element ◽  
Point Of View ◽  
Design Parameters ◽  
Discrete Elements ◽  
Bulk Materials ◽  
Design Features ◽  
Element Method

Studying the influence of continuous centrifugal mixers design features on their smoothing ability. The methods used are discrete elements, mathematical modeling and regression analysis. The paper considers five continuous centrifugal mixers designs with conical and parabolic rotors. The mixers design features are determined, allowing to change their smoothing ability. Mathematical models of the bulk materials particles movement inside each mixer have been developed based on the discrete element method. The considered mixers reaction to a step change of the key component amount is investigated. The transients parameters are calculated and the particles average residence time in the mixer is determined. It is established that the introduction of turbulizers in the mixers design increases the particles kinetic energy, which leads to a decrease in their residence time in the mixer. Moreover, the absence of a turbulizer leads to a decrease in the mixing intensity. It was also found that the most effective way to increase the mixer smoothing ability is the introduction of additional rotors. In terms of the technological and design parameters combination, the use of mixers with a conical rotor and a turbulizer is the most effective from the point of view for increasing the smoothing ability. On the discrete element method basis, the bulk materials particles movement models in continuous centrifugal mixers of five designs have been developed. The influence of the mixers design features on their smoothing ability and average mixing time is determined. The results obtained allow us to select the appropriate mixer design according to the specified requirements for smoothing ability.

Applicable Contact Force Models for the Discrete Element Method: The Single Particle Perspective

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
H. Kruggel-Emden ◽  
S. Wirtz ◽  
V. Scherer
Keyword(s):  
Discrete Element Method ◽  
Granular Materials ◽  
Experimental Studies ◽  
Spherical Shape ◽  
Discrete Element ◽  
Industrial Applications ◽  
Contact Forces ◽  
Experimental Investigations ◽  
Simulation Techniques ◽  
Element Method

Several processes in nature as well as many industrial applications involve static or dynamic granular materials. Granulates can adopt solid-, liquid-, or gaslike states and thereby reveal intriguing physical phenomena not observable in its versatility for any other form of matter. The frequent occurrence of phase transitions and the related characteristics thereby strongly affect their processing quality and economics. This situation demands for prediction methods for the behavior of granulates. In this context simulations provide a feasible alternative to experimental investigations. Several different simulation approaches are applicable to granular materials. The time-driven discrete element method turns out to be not only the most complex but also the most general simulation approach. Discrete element simulations have been used in a wide variety of scientific fields for more than 30 years. With the tremendous increase in available computer power, especially in the past years, the method is more and more developing to the state of the art simulation technique for granular materials not only in science but also in industrial applications. Several commercial software packages utilizing the time-driven discrete element method have emerged and are becoming more and more popular within the engineering community. Despite the long time of usage of the time-driven discrete element method, model advances derived and theoretical and experimental studies performed in the different branches of application lack harmonization. They thereby provide potential for improvements. Therefore, the scope of this paper is a review of methods and models for contact forces based on theoretical considerations and experimental data from literature. Particles considered are of spherical shape. Through model advances it is intended to contribute to a general enhancement of simulation techniques, which help improve products and the design of the related equipment.

scholarly journals Mechanical analysis and research of the conveyor belt of plane turning belt conveyor based on Discrete Element Method

2017 ◽  
Vol 41 (1) ◽  
pp. 55-62
Author(s):  
De-yong Li ◽  
Shuang Wang ◽  
Kun Hu
Keyword(s):  
Discrete Element Method ◽  
Inclination Angle ◽  
Turning Point ◽  
Elevation Angle ◽  
Load Condition ◽  
Discrete Element ◽  
Conveyor Belt ◽  
Design Parameters ◽  
Belt Conveyor ◽  
Element Method

In view of the size and the change of the load force of the conveyor belt at the turning point of the plane turning belt conveyor, the influencing factors of the stress of the conveyor belt at the turning point of the plane turning belt conveyor under full load condition are analyzed. A three dimensional model of the turning point of the plane turning belt conveyor is established. Combined with previous research experience, the formula for calculating the load is put forward. Based on discrete element method, multiple sets of internal curve elevation angle and the belt speed are used for dynamic simulation analysis. The results showed that the middle of conveyor belt is the most stressed, the lateral force second, the force of the inner conveyor belt is the least. Outside force increases with the increase of speed; there is no change in the middle band; the inner band force decreases with the increase of the velocity. Outside force decreases with the decrease of the inclination angle. With the change of the inclination angle, the force is basically unchanged. With the decreasing of the inclination angle, the force increases gradually. By optimizing the design parameters of the plane turning belt conveyor, the force of belt is reduced, and the service life of belt is improved.

scholarly journals Slope Failure of Noncohesive Media Modelled with the Combined Finite–Discrete Element Method

2019 ◽  
Vol 9 (3) ◽  
pp. 579 ◽  
Author(s):  
Xudong Chen ◽  
Hongfan Wang
Keyword(s):  
Discrete Element Method ◽  
Large Scale ◽  
Slope Failure ◽  
Discrete Element ◽  
Material Point ◽  
Contact Forces ◽  
Discrete Elements ◽  
Failure Behaviour ◽  
Particle Hydrodynamics ◽  
Element Method

Slope failure behaviour of noncohesive media with the consideration of gravity and ground excitations is examined using the two-dimensional combined finite–discrete element method (FDEM). The FDEM aims at solving large-scale transient dynamics and is particularly suitable for this problem. The method discretises an entity into a couple of individual discrete elements. Within each discrete element, the finite element method (FEM) formulation is embedded so that contact forces and deformation between and of these discrete elements can be predicted more accurately. Noncohesive media is simply modelled with assembly of individual discrete elements without cohesion, that is, no joint elements need to be defined. To validate the effectiveness of the FDEM modelling, two examples are presented and compared with results from other sources. The FDEM results on gravitational collapse of rectangular soil heap and landslide triggered by the Chi-Chi earthquake show that the method is applicable and reliable for the analysis of slope failure behaviour of noncohesive media through comparison with results from other known methods such as the smoothed particle hydrodynamics (SPH), the discrete element method (DEM) and the material point method (MPM).

scholarly journals Investigating the Combined Effects of Inherent and Stress-Induced Anisotropy on the Mechanical Behavior of Granular Materials Using Three-Dimensional Discrete Element Method

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Xinran Chen ◽  
Jinsong Qian ◽  
Lei Zhang ◽  
Jianming Ling
Keyword(s):  
Discrete Element Method ◽  
Mechanical Behavior ◽  
Granular Materials ◽  
Three Dimensional ◽  
Discrete Element ◽  
Contact Forces ◽  
Combined Effects ◽  
Induced Anisotropy ◽  
Stress Induced Anisotropy ◽  
Element Method

The three-dimensional discrete element method (DEM) was employed to investigate the combined effects of inherent and stress-induced anisotropy of granular materials. The particles were modeled following real particle shapes. Both isotropic and inherently anisotropic specimens were prepared, and then true triaxial numerical tests were conducted using different intermediate principle stress ratios (b). The results indicate that the oriented particles in the anisotropic specimens form strong contacts in their long axis direction in the early stages of shearing, which restrains the contraction of the specimens. As the strain increases, the oriented particles start to rotate and slide, which results in shorter contraction stages and fewer number of interparticle contacts with peak values compared to the isotropic specimens. In addition, the increase in b values aggravates the rotating and sliding of particles in the inherently anisotropic specimens and restrains the contraction of the granular and the increase of contact forces. As a result, the inherent anisotropy reduces the effects of stress-induced anisotropy on the mechanical behavior of granular materials.

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