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

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.

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

Applied Engineering in Agriculture ◽

10.13031/aea.14381 ◽

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.

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

Agriculture ◽

10.3390/agriculture12010038 ◽

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.

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

INMATEH Agricultural Engineering ◽

10.35633/inmateh-64-46 ◽

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.

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

Processes ◽

10.3390/pr7090561 ◽

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.

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

INMATEH Agricultural Engineering ◽

10.35633/inmateh-63-42 ◽

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.

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

10.21203/rs.3.rs-122784/v1 ◽

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.

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Discrete Element Analysis of Friction Coefficient on Granular Accumulation

Advanced Engineering Forum ◽

10.4028/www.scientific.net/aef.2-3.894 ◽

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.

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The Research of Static Friction Coefficient Measure Technology and Calibration Method for Traffic Engineering

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.128-129.1493 ◽

2011 ◽

Vol 128-129 ◽

pp. 1493-1496 ◽

Cited By ~ 1

Author(s):

Xue Feng Ma ◽

Dong Hua Guo ◽

Yu Hong Lu

Keyword(s):

Friction Coefficient ◽

Traffic Engineering ◽

Static Friction ◽

Calibration Method ◽

Inclined Plane ◽

Plane Method ◽

Engineering Communication ◽

Static Friction Coefficient ◽

Equipment System

The measure technology of static friction coefficient of traffic engineering communication and cable ducts by using inclined plane method is introduced in this paper. The calibrated method for that equipment system of static friction coefficient is discussed, furthermore.

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CONSTRUCTION OF A DISCRETE ELEMENT MODEL OF BUCKWHEAT SEEDS AND CALIBRATION OF PARAMETERS

INMATEH Agricultural Engineering ◽

10.35633/inmateh-64-17 ◽

2021 ◽

pp. 175-184

Author(s):

Bing Xu ◽

Yanqing Zhang ◽

Qingliang Cui ◽

Shaobo Ye ◽

Fan Zhao

Keyword(s):

Stainless Steel ◽

Friction Coefficient ◽

Static Friction ◽

Discrete Element ◽

Rolling Friction ◽

Restitution Coefficient ◽

Steel Rolling ◽

Static Friction Coefficient ◽

Contact Parameters ◽

Rolling Friction Coefficient

In view of the lack of seeds contact parameters that can be used as a reference for the design of key mechanical components such as buckwheat planting, harvesting, and processing, this study combines simulation optimization design experiments and physical experiments to calibrate the parameters of simulated discrete element of buckwheat seeds. The non-spherical particle model of buckwheat seeds was established using the automatic filling method, and the simulation accumulating test and physical accumulating test were carried out using the bottomless conical cylinder lifting method; the repose angle of buckwheat seeds was taken as the response value, and the initial parameters were screened for significance based on the Plackett-Burman test; and a second-order regression model of the error value for the repose angle and the significance parameter was established based on the steepest climb test and Box-Behnken test. On this basis, the minimum error value of the repose angle was used as the goal to optimize the significance parameter, the optimal combination of contact parameters was obtained, and parameter validation tests were carried out. The significance screening test showed that the buckwheat-buckwheat static friction coefficient, the buckwheat-stainless steel rolling friction coefficient, and the buckwheat-stainless steel restitution coefficient had significant effects on the repose angle of buckwheat (P<0.05). The optimization test showed that the buckwheat-buckwheat static friction coefficient was 0.510, the buckwheat-stainless steel rolling friction coefficient was 0.053, and the buckwheat-stainless steel restitution coefficient was 0.492. The validation test showed that the repose angle of buckwheat seeds under such parameter was 25.39°, and the error with the repose angle of the physical test was 0.55%, which indicated that the optimal parameter combination was reliable. This study could provide a seed model and simulation contact parameters for the research and development of buckwheat sowing, threshing and hulling machinery.

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Calibration and Verification Test of Lily Bulb Simulation Parameters Based on Discrete Element Method

Applied Sciences ◽

10.3390/app112210749 ◽

2021 ◽

Vol 11 (22) ◽

pp. 10749

Author(s):

Zhenwei Dai ◽

Mingliang Wu ◽

Zhichao Fang ◽

Yongbo Qu

Keyword(s):

Friction Coefficient ◽

Static Friction ◽

Element Model ◽

Discrete Element ◽

Discrete Element Model ◽

Recovery Coefficient ◽

Q235 Steel ◽

Dynamic Friction Coefficient ◽

Contact Parameters ◽

Lily Bulb

In the simulation analysis of the lily harvesting process, the intrinsic parameters of the lily bulb and the contact parameters between the lily bulb and the lily mechanized harvesting equipment (Q235 steel) are deficient. Thus, the three-axis size, density, moisture content, Poisson’s ratio, elastic modulus, and other parameters of lily bulbs are measured in this paper with lily bulbs as the research object. Moreover, the discrete element model of the lily bulb was established using 3D scanning technology. The contact parameters between the lily bulb and Q235 steel were calibrated through bench test and simulation parameter test. The relative error between the measured value of the lily bulb accumulation angle and the simulated value is taken as response value to calibrate three parameters (collision recovery coefficient, static friction coefficient, and dynamic friction coefficient between lily bulbs). A regression model of the relative error of the stacking angle and three parameters is established, and the response surface is optimized. The results demonstrate that collision recovery coefficient, static friction coefficient, and dynamic friction coefficient between lily bulb and Q235 steel are 0.301, 0.423, and 0.063, respectively; these coefficients between lily bulbs are 0.455, 0.425, and 0.158, respectively. Additionally, a better combination of parameters is adopted to perform the simulation stacking test. The measured stacking angle is 32.31°, which is 0.34% in error with the stacking angle obtained by the physical stacking test. The test results suggest that the discrete element model and contact parameters of the lily bulb can be used in the discrete element simulation test. Furthermore, these research results could provide references for simulation tests, such as mechanized harvesting and post-harvest processing, of lily.

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