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

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.

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 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.

scholarly journals Analysis of Adhesion between Wet Clay Soil and Rotary Tillage Part in Paddy Field Based on Discrete Element Method

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 845
Author(s):  
Jian Cheng ◽  
Kan Zheng ◽  
Junfang Xia ◽  
Guoyang Liu ◽  
Liu Jiang ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Regression Model ◽  
Paddy Field ◽  
Clay Soil ◽  
Static Friction ◽  
Discrete Element ◽  
Rolling Friction ◽  
Soil Particles ◽  
Simulation Parameters ◽  
Element Method

To analyze the process of wet clay soil adhering to the rotary tillage part during rotary tillage in paddy field, simulation tests were carried out based on the discrete element method (DEM) in this study. The Plackett-Burman (PB) test was applied to obtain simulation parameters that significantly affected the soil adhesion mass. The Box-Behnken design (BBD) based on the principle of response surface method (RSM) was used to establish a regression model between significant parameters and soil adhesion mass. The soil adhesion mass obtained from the actual soil bin test as the response value was brought into the regression model. The optimal simulation parameters were obtained: the particle-particle coefficient of rolling friction, the particle-geometry coefficient of static friction, and the particle-particle JKR (Johnson-Kendall-Roberts) surface energy were 0.09, 0.81, and 61.55 J·m−2, respectively. The reliability of the parameters was verified by comparing the soil adhesion mass obtained under the optimal simulation parameters with the actual test value, and the relative error was 1.84%. Analysis of the rotary tillage showed that soil adhesion was mainly concentrated in the sidelong section of the rotary blade. The maximum number of upper soil particles adhering to the rotary tillage part was 2605 compared to the middle soil and lower soil layers. The longer the distance the rotary tillage part was operated in the soil for, the more soil particles would adhere to it. This study can provide a reference for the rational selection of simulation parameters for rotary tillage and the analysis of soil adhesion process in rotary tillage.

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.

scholarly journals Particle Directional Conveyance under Longitudinal Vibration by considering the Trough Surface Texture: Numerical Simulation Based on the Discrete Element Method

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Huazhi Chen ◽  
Shengyuan Jiang ◽  
Rongkai Liu ◽  
Weiwei Zhang
Keyword(s):  
Numerical Simulation ◽  
Friction Coefficient ◽  
Discrete Element Method ◽  
Longitudinal Vibration ◽  
Cumulative Effect ◽  
Static Friction ◽  
Discrete Element ◽  
Rolling Friction ◽  
Simulation Based ◽  
Element Method

Particles can move directionally in a trough with finlike asperities under longitudinal vibrations. Here, we present an analysis of the particle conveyance mechanism and the influence of the asperity shape on the particle conveyance capacity by employing a numerical simulation based on the discrete element method (DEM). A dynamic-static matching method is proposed to characterize the three microcontact parameters in the simulation: the restitution coefficient, static friction coefficient, and rolling friction coefficient. The simulation shows that the asymmetric force induced by the finlike asperities and its cumulative effect over time lead to the particle directional conveyance. The conveyance velocity increases with increasing vibration time and is related to the median coordination number. The asperity height and slope inclination angles determine the trough shape and distance between two asperities directly. An undersized or oversized distance reduces the steady conveyance velocity. We find the optimal distance to be between one and two particle diameters.

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

Agriculture ◽  
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.

scholarly journals Discrete element method approach to modelling VPP dampers

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.

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

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.

A Surrogate Discrete Element Method for Terramechanics Simulation of Granular Locomotion

2015 ◽  
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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