scholarly journals Calibration and Tests for the Discrete Element Simulation Parameters of Fallen Jujube Fruit

Agriculture ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 38
Author(s):  
Gaokun Shi ◽  
Jingbin Li ◽  
Longpeng Ding ◽  
Zhiyuan Zhang ◽  
Huizhe Ding ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Simulation Model ◽  
Static Friction ◽  
Discrete Element ◽  
Angle Of Repose ◽  
Average Error ◽  
Dem Simulation ◽  
Static Friction Coefficient ◽  
Jujube Fruit ◽  
Simulation Parameters

Discrete element method (DEM) simulation is an important method to analyze the interaction relationship between materials and equipment, and to develop machinery and/or equipment. However, it is necessary to input specific simulation parameters when establishing a DEM simulation model. In this study, the interval values were measured through angle of repose tests of fallen jujube fruit (FJF), and the simulation angle of repose tests for FJF were established with EDEM software (DEM Solutions Ltd. Edinburgh, Scotland, UK). Then, the Plackett-Burman design, steepest ascent search experiment, and center composite design experimental methods were utilized to obtain the specific values of the simulation parameters from the interval values. The results showed that significant influencing factors in the simulation angle of repose include the Poisson’s ratio, the static friction coefficient between FJF, and the static friction coefficient between FJF and the steel plate, for which the optimal values were 0.248, 0.480, and 0.309, respectively. The angle of repose tests’ results showed that the error was 0.53% between the simulation angle of repose (29.69°) and the angle of repose (29.85°). In addition, the flow rate test results showed that the average error was 5.84% between the physical and simulation tests. This indicated that the calibrated parameters were accurate and reliable, and that the simulation model can accurately represent the physical tests. Consequently, this study provides an EDEM model of FJF that was essential in designing machinery and equipment through the EDEM simulation method.

scholarly journals Calibration and Verification of Dynamic Particle Flow Parameters by the Back-Propagation Neural Network Based on the Genetic Algorithm: Recycled Polyurethane Powder

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3350
Author(s):  
Ping He ◽  
Yiwei Fan ◽  
Banglong Pan ◽  
Yinfeng Zhu ◽  
Jing Liu ◽  
...  
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Friction Coefficient ◽  
Back Propagation ◽  
Static Friction ◽  
Discrete Element ◽  
Calibration Method ◽  
Angle Of Repose ◽  
Recovery Coefficient ◽  
Static Friction Coefficient

The discrete element method (DEM) is commonly used to study various powders in motion during transportation, screening, mixing, etc.; this requires several microscopic parameters to characterize the complex mechanical behavior of the particles. Herein, a new discrete element parameter calibration method is proposed to calibrate the ultrafine agglomerated powder (recycled polyurethane powder). Optimal Latin hypercube sampling and virtual simulation experiments were conducted using the commercial DEM software; the microscopic variables included the static friction coefficient between the particles, collision recovery coefficient, Johnson–Kendall–Roberts surface energy, static friction coefficient between the particles and wall, and collision recovery coefficient. A predictive model based on genetic-algorithm-optimized feedforward neural network (back propagation) was developed to calibrate the microscopic DEM simulation parameters. The cycle search algorithm and mean-shift cluster analysis were used to confirm the input parameters’ range by comparing the mean value of the dynamic angle of repose measured via the batch accumulation test. These parameters were verified by the baffle lifting method and the rotating drum method. This calibration method, once successfully developed, will be suitable for use in a variety of fine viscous powder dynamic flow conditions.

Calibration and Experimental Validation of Contact Parameters for Oat Seeds for Discrete Element Method Simulations

2021 ◽  
Vol 37 (4) ◽  
pp. 605-614
Author(s):  
Lingxin Geng ◽  
Jiewen Zuo ◽  
Fuyun Lu ◽  
Xin Jin ◽  
Chenglong Sun ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Discrete Element Method ◽  
Static Friction ◽  
Discrete Element ◽  
Rolling Friction ◽  
Angle Of Repose ◽  
Static Friction Coefficient ◽  
Contact Parameters ◽  
Rolling Friction Coefficient ◽  
Element Method

Highlights The static friction coefficient and rolling friction coefficient of oat seeds were calibrated by the discrete element method. Two representative oat varieties were selected. The hollow cylinder method and sidewall collapse method were used together to reduce the test error. Abstract . Hulless and shelled oat are two types of oat with major differences in physical appearance. To study the contact parameters between the two different oat seed types, these parameters were delineated with the discrete element method and graphic image processing technology. Using plexiglass as the contact material, the experiments used two different angle of repose measurement methods—hollow cylinder and collapse sidewall devices, to perform bench and simulation experiments on the two different oats. Under different measurement methods, bench experiments measured the angles of repose of the two oat seed types at 33.19°, 33.82° and 22.45°, 23.57°; the static friction coefficient and rolling friction coefficient were the experimental factors, and the angle of repose was the experimental indicator in the simulation. The steepest climbing experiment determined the optimal range of the experimental factor, and the regression equation between the static friction coefficient, rolling friction coefficient and angle of repose was established by a quadratic orthogonal rotation combination experiment. Finally, the angles of repose measured by the bench experiment with the two different measurement methods were treated as target values, the coefficient of static friction and the coefficient of rolling friction were solved; the coefficient of static friction between hulless oats was 0.36, and the coefficient of rolling friction between hulless oats was 0.052; the coefficient of static friction between shelled oats was 0.24, and the coefficient of rolling friction between shelled oats was 0.036. The obtained contact parameters between seeds were input into EDEM, the simulation and bench experiment results were verified. The difference between the simulation results and the actual values was within 3%. The angle of repose of oats after calibration was close to the actual situation, and the calibration results had high reliability and provided a referencefor the measurement of contact parameters between other agricultural crop seeds. Keywords: Calibration, Contact parameters, Discrete element method, Oat.

scholarly journals Analysis of the Effect of Ventilation Bars on the Packing Structure of Sinter Bed by DEM Simulation

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3836
Author(s):  
Shingo Ishihara ◽  
Kizuku Kushimoto ◽  
Junya Kano
Keyword(s):  
Shear Flow ◽  
Discrete Element Method ◽  
Adhesion Force ◽  
Sinter Machine ◽  
Discrete Element ◽  
Angle Of Repose ◽  
Dem Simulation ◽  
Packing Structure ◽  
Experimental Values ◽  
Simulation Parameters

The effect of ventilation bars on the porosity of a sinter bed charged on a sinter machine was investigated. The behavior of the sinter feed was calculated by discrete element method (DEM) simulation. By taking into account the adhesion force, the sinter feed in the wet state was represented and the simulation parameters were determined to reproduce the experimental values of the angle of repose. The porosity of the sinter bed was calculated, and the mechanism of the formation of the packing structure and the cause of the distribution of porosity in each region were clarified. As a result, it is shown that in the case of shear flow, the higher the powder pressure during flow, the higher the porosity.

scholarly journals ANALYSIS AND CALIBRATION OF PARAMETERS OF BUCKWHEAT GRAIN BASED ON THE STACKING EXPERIMENT

2021 ◽  
pp. 467-476
Author(s):  
Rong Fan ◽  
Qingliang Cui ◽  
Yanqing Zhang ◽  
Qi Lu
Keyword(s):  
Friction Coefficient ◽  
Static Friction ◽  
Calibration Method ◽  
Simulation Test ◽  
Physical Test ◽  
Factors Affecting ◽  
Static Friction Coefficient ◽  
Significant Difference ◽  
Simulation Parameters ◽  
Significant Factors

The stacking test based on response surface method (RSM) was carried out to calibrate the simulation parameters of buckwheat grain by discrete element method (DEM). The static friction coefficient of buckwheat-buckwheat and that of buckwheat-steel are significant factors affecting the repose angle. A quadratic polynomial model for the repose angle and the 2 significant parameters was established and optimized. The optimal combination was obtained: buckwheat-buckwheat static friction coefficient of 0.482, buckwheat-steel static friction coefficient of 0.446. It was found that there was no significant difference between the results of the simulation test and physical test (P>0.05), indicating that the parameter calibration method based on RSM is feasible. The calibrated parameters can provide reference to the simulation of buckwheat production process and machineries design.

scholarly journals Discrete Element Method (DEM) and Experimental Studies of the Angle of Repose and Porosity Distribution of Pellet Pile

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 561
Author(s):  
Han Wei ◽  
Meng Li ◽  
Ying Li ◽  
Yao Ge ◽  
Henrik Saxén ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Friction Coefficient ◽  
Gas Flow ◽  
Experimental Studies ◽  
Static Friction ◽  
Furnace Operation ◽  
Angle Of Repose ◽  
Physical Parameters ◽  
Porosity Distribution ◽  
Static Friction Coefficient

The lumpy zone in a blast furnace is composed of piles formed naturally during burden charging. The properties of this zone have significant effects on the blast furnace operation, including heat and mass transfer, chemical reactions and gas flow. The properties of the layers mainly include the angle of repose and porosity distribution. This paper introduces two methods, the Discharging Method and the Lifting Method, to study the influence of the packing method on the angle of repose of the pile. The relationships of the angle of repose and porosity with physical parameters are also investigated. The porosity distribution in the bottom of a pile shows a decreasing trend from the region below the apex to the center. The coordination number of the particles is employed to explain this change. The maximum of the frequency distribution of it was found to show a negative correlation to the static friction coefficient, but becomes insensitive to the parameter as the static friction coefficient increases above 0.6.

scholarly journals USING THE DISCRETE ELEMENT METHOD TO ANALYZE AND CALIBRATE A MODEL FOR THE INTERACTION BETWEEN A PLANTING DEVICE AND SOIL PARTICLES

2021 ◽  
pp. 413-424
Author(s):  
Fandi Zeng ◽  
Xuying Li ◽  
Yongzhi Zhang ◽  
Zhiwei Zhao ◽  
Cheng Cheng
Keyword(s):  
Friction Coefficient ◽  
Mass Flow ◽  
Dynamic Behaviour ◽  
Static Friction ◽  
Discrete Element ◽  
Soil Restoration ◽  
Contact Interface ◽  
Steel Rolling ◽  
Soil Particles ◽  
Static Friction Coefficient

Dynamic soil behaviour at the contact interface during transplanting makes it difficult to ensure transplanting quality. To solve this problem, the Hertz-Mindlin with bonding contact model was used to calibrate the parameters of soils in Inner Mongolia. Based on the response surface design principle, four-factor and three-level tests were performed using the repose angle as an evaluation index, and the following influence factors were considered: the soil-soil restoration coefficient, the soil-steel restoration coeficient, the soil-steel static friction coefficient and the soil-steel static friction coefficient. A regression model was analysed, and an optimization procedure yielded the following optimum combination of parameters: a soil-soil restoration coefficient of 0.45, a soil-steel restoration coefficient of 0.35, a soil-steel static friction coefficient of 0.85 and a soil-steel rolling friction coefficient of 0.13. This optimal combination was used to simulate the soil at the contact interface. The particle dynamic behaviour and soil particle mass flow were used to analyse the soil dynamic behaviour, showing that the average mass flow during the gradual opening of the duckbilled planter tends to increase over time; when the duckbilled planter gradually leaves soil, the contact interface of soil particles in the corner of the duckbilled planter unit causes a reduction in the fluctuation range of the soil mass flow, which exhibits a wave-like change. After the duckbilled planter has left soil, the contact interface of the soil changes tends to stabilize. The duckbilled planter-soil discrete element simulation model was verified. The results of this study provide a reference for the optimal design of a duckbilled planter structure.

scholarly journals Measurement and Calibration of the Parameters for Discrete Element Method Modeling of Rapeseed

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 605
Author(s):  
Xiulong Cao ◽  
Zehua Li ◽  
Hongwei Li ◽  
Xicheng Wang ◽  
Xu Ma
Keyword(s):  
Discrete Element Method ◽  
Static Friction ◽  
Discrete Element ◽  
Rolling Friction ◽  
Particulate Material ◽  
Angle Of Repose ◽  
Model Parameters ◽  
Dem Simulation ◽  
Response Surface Optimization ◽  
Element Method

The discrete element method (DEM) for modeling the behavior of particulate material is highly dependent on the use of appropriate and accurate parameters. In this study, a seed metering DEM simulation was used to measure, calibrate, and verify the physical and interactional parameters of rapeseed. The coefficients of restitution and static friction between rapeseeds and three common materials (aluminum alloy, acrylic, and high-density polyethylene) were measured using free drop and sliding ramp tests, respectively. The angle of repose was determined using a hollow cylinder experiment, which was duplicated using a DEM simulation, to examine the effects of static and rolling friction coefficients on the angle of repose. Response surface optimization was performed to determine the optimized model parameters using a Box–Behnken design test. A metering device was made with three materials, and rapeseed seeding was simulated at different working speeds to verify the calibrated parameters. The validation results showed that the relative errors between the seed metering model and experiments for the single qualified seeding, missed seeding, and multiple seeding rates were −0.15%, 3.29%, and 5.37%, respectively. The results suggest that the determined physical and interactional parameters of rapeseed can be used as references for future DEM simulations.

Determination of the friction coefficient of coal particles by discrete element simulation and experimentation

2020 ◽  
Author(s):  
Jinrong CHAI ◽  
Shifeng WANG ◽  
Zihao ZHOU ◽  
Guohua LI ◽  
Xunan LIU
Keyword(s):  
Stainless Steel ◽  
Friction Coefficient ◽  
Static Friction ◽  
Discrete Element ◽  
Rolling Friction ◽  
Angle Of Repose ◽  
Discrete Element Simulation ◽  
Element Simulation ◽  
Coal Particles ◽  
Rolling Friction Coefficient

Abstract The friction coefficient of coal is the main factor influencing the results of discrete element simulation. In this study, the friction coefficient of coal was determined using a self-made testing instrument for measuring the static friction coefficient and an automatic cylinder lifting device on the basis of discrete element simulation, image processing, and orthogonal testing. The correlations between the angle of repose of coal particles, the rolling friction coefficient between coal particles, and the rolling friction coefficient between the coal particles and stainless steel were evaluated by linear regression analysis. Results indicated that the dependent variable (angle of repose of coal particles) was linearly correlated to the two independent variables (rolling friction factor between the coal particles, as well as the rolling friction factor between the coal and the stainless steel). The angle of repose of the coal particles was largely affected by the rolling friction coefficient between the coal particles but not by the rolling friction coefficient between the coal particle and stainless steel. Moreover, the static friction coefficient between the coal particles was 0.53, and that between the coal particle and the stainless steel was 0.38. The rolling friction coefficient between the coal particles was 0.048, and that between the coal particles and the stainless steel was 0.03. These friction coefficients were used to simulate the bottomless cylinder test of the coal particles. The angle of repose in the simulation test was 30.77°, whereas that in the real test was 31.47°; the relative error was 2.22%. Therefore, no significant difference in the results was indicated between the simulation test and the real test, verifying the effectiveness of the method used to determine friction coefficients. The aforementioned technique can be applied to determine the friction coefficient of lump coal particles.

scholarly journals Discrete Element Analysis of Friction Coefficient on Granular Accumulation

2011 ◽  
Vol 2-3 ◽  
pp. 894-899
Author(s):  
Qin Liang Li ◽  
Bin Zhao ◽  
Bo Wang ◽  
Bang Chun Wen
Keyword(s):  
Friction Coefficient ◽  
Static Friction ◽  
Discrete Element ◽  
Rolling Friction ◽  
Point Of View ◽  
Angle Of Repose ◽  
Element Analysis ◽  
Dem Analysis ◽  
The Impact ◽  
Rolling Friction Coefficient

Discrete element method (DEM) is applied to study the granular accumulation problem. Using Herz-Mindlin (no slip) model to simulate particles and container model is also established by software. When the container elevates, the process of granular falling and collision can be ob-served. Detailed analysis of that the impact of static and rolling friction coefficient for particles - particles, particles - flat on angle of repose is accomplished. The variation law is also further val-idated from the energy point of view. The results show that rolling friction has a greater impact on angle of repose than static friction, and rolling friction coefficient among particles play the more prominent role in the two kinds of rolling friction. The research method and results provide a the-oretical reference for the granular movement and DEM analysis.

scholarly journals ANALYSIS AND CALIBRATION OF QUINOA GRAIN PARAMETERS USED IN A DISCRETE ELEMENT METHOD BASED ON THE REPOSE ANGLE OF THE PARTICLE HEAP

2020 ◽  
Vol 61 (2) ◽  
pp. 77-86 ◽  
Author(s):  
Fei Liu ◽  
Dapeng Li ◽  
Tao Zhang ◽  
Zhen Lin
Keyword(s):  
Friction Coefficient ◽  
Discrete Element Method ◽  
Static Friction ◽  
Rolling Friction ◽  
Optimal Parameters ◽  
Dem Simulation ◽  
Static Friction Coefficient ◽  
Dem Model ◽  
Rolling Friction Coefficient ◽  
Element Method

An optimization method based on a regression model was established by combining physical experiments, and an extended distinct element method (EDEM) simulation was proposed to address the difficult problem of obtaining the contact characteristic parameters used in the discrete element method (DEM) model of quinoa grains and for calibrating the parameters of the quinoa DEM model. The Plackett-Burman test was designed using Design-Expert software to screen the parameters of the quinoa DEM model, and the quinoa-quinoa static friction coefficient, quinoa-polylactic acid (PLA) static friction coefficient and quinoa-quinoa rolling friction coefficient were found to have significant effects on the repose angle. The optimal value intervals of the parameters with a significant impact on the repose angle were determined using the steepest ascent test. A regression model of the repose angle and the parameters with a significant impact on the repose angle was then established with the Box-Behnken design and further optimized, and the combination of optimal parameters was as follows: 0.26 for the quinoa-quinoa static friction coefficient (E), 0.38 for the quinoa-PLA static friction coefficient (F), and 0.08 for the quinoa-quinoa rolling friction coefficient (G). Lastly, the optimal combination was used in the verification performed by the DEM simulation, and the error between the simulated repose angle and the target repose angle was 0.86%. These findings indicated that it was feasible to use the response surface optimization to calibrate the parameters required for quinoa DEM simulation and that the combination of optimal parameters can provide a reference for selecting the characteristic contact parameters used in quinoa DEM simulation.

Sign in / Sign up

Export Citation Format

Share Document