In this study,a simulation model of peanut pod particles during harvest in saline soil was tested to calibrate contact parameters.Discrete meta-fill models of peanut pods were generated by a 3D meter and EDEM software...In this study,a simulation model of peanut pod particles during harvest in saline soil was tested to calibrate contact parameters.Discrete meta-fill models of peanut pods were generated by a 3D meter and EDEM software.The range of values of contact parameters for peanut pods was measured by conducting collision and other tests using a homemade test rig.The parameters that affect the significance of the simulation process of stacking angle were screened by the Plackett-Burman experiment,the steepest ascent experiment,and the Box-Behnken experiment.An optimization test determined the optimal simulation model parameters:The peanut pods had a Poisson’s ratio of 0.386 and a shear modulus of 3.04 MPa.The coefficient of recovery for pods-pods collisions was 0.335,the coefficient of static friction was 0.854,and the coefficient of rolling friction was 0.346.The coefficient of recovery of collision between the pods-65Mn steel was 0.339,the coefficient of static friction was 0.589,and the coefficient of rolling friction was 0.159.The test results showed a relative error of 0.42%between the stacking angle bench and simulation tests.The results can provide data support for studying the discrete metamaterial characterization of peanut pods.展开更多
Both linear-spring-dashpot （LSD） and non-linear Hertzian-spring-dashpot （HSD） contact models are commonly used for the calculation of contact forces in Discrete Element Method （DEM） simulations of granular syste...Both linear-spring-dashpot （LSD） and non-linear Hertzian-spring-dashpot （HSD） contact models are commonly used for the calculation of contact forces in Discrete Element Method （DEM） simulations of granular systems. Despite the popularity of these models, determination of suitable values for the contact parameters of the simulated particles such as stiffness, damping coefficient, coefficient of restitution, and simulation time step, is not altogether obvious. In this work the relationships between these contact parameters for a model system where a particle impacts on a flat base are examined. Recommendations are made concerning the determination of these contact parameters for use in DEM simulations.展开更多
Discrete element method was used to study and analyze the interaction between rice straws and between rice straw and agricultural machinery parts,thereby providing a scientific basis for post-harvest paddy field proce...Discrete element method was used to study and analyze the interaction between rice straws and between rice straw and agricultural machinery parts,thereby providing a scientific basis for post-harvest paddy field processing.Calibrations of rice straw-rice straw,rice straw-agricultural machinery part contact parameters(collision recovery coefficient,static friction coefficient and rolling friction coefficient)constitute an important prerequisite for the discrete element research process.In this study,the collision recovery coefficients of rice straw-steel and rice straw-rice straw were 0.230 and 0.357,respectively,which were calibrated by the collision method.The static friction coefficient and rolling friction coefficient of rice straw-steel were 0.363 and 0.208 respectively,which were calibrated by the inclined plate method and the slope method.The static friction coefficient and rolling friction coefficient of rice straw-rice straw were 0.44 and 0.07,respectively,which were calibrated by the split cylinder method.The paired t-test showed insignificant differences between calibration parameter simulation results and the physical test values(p>0.05).Taking the angle of repose that reflecting rice straw flow and friction characteristics as the evaluation index,the verification tests of the above calibration values indicated that the simulated angle of repose has no significant difference from the physical test value(p>0.05).The side plate lifting test on rice straw of different lengths showed no significant difference between the simulated angle of repose and the physical test value(p>0.05).This study can provide a basis for contact parameters choice in discrete element simulation analysis with rice straw-rice straw and rice straw-agricultural machinery parts as the research object.The calibration method can provide a reference for the contact parameter calibration of other crop straws.展开更多
In view of the fact that the existing cotton stem simulation models are simplified and have a large discrepancy from the actual appearance and the contact parameters have not been calibrated.In this study,the simulati...In view of the fact that the existing cotton stem simulation models are simplified and have a large discrepancy from the actual appearance and the contact parameters have not been calibrated.In this study,the simulation model and numerical simulation were established using the discrete element software EDEM.Then a second-order response model between contact parameters and repose angle had been constructed.The test result showed that the static friction coefficient,rolling friction coefficient,and coefficient of restitution between cotton stems were crucial factors affecting the repose angle.The determination coefficient corrected determination coefficient and p-value of the second-order response model were R^(2)=0.959,R^(2)_(adj)=0.921,and p<0.0001 respectively.The error values of the comparison between the simulation test results and the corresponding physical test values were all less than 10%,which showed that the model was reliable and had high interpretation and predictability,this study can provide a certain theoretical basis and data support for the setting of contact parameters in the data simulation of cotton stem harvesting and processing,mechanically-harvested film residue crushing and film stem separation,etc.展开更多
In order to identify the uncertain parameters of a bolted joint finite element model,a simple and applicable way of parameter identification is introduced.By utilizing numerical simulation with the Abaqus software and...In order to identify the uncertain parameters of a bolted joint finite element model,a simple and applicable way of parameter identification is introduced.By utilizing numerical simulation with the Abaqus software and experimental investigation with the MTS material testing system,the tangential force-displacement curves that reflect the characteristics of the bolted joint were acquired.On the basis of this,by employing the response surface methodology（RSM）and genetic algorithms（GAs）,parameters in the FEM model were identified.The force-displacement curves by both virtual and experimental approaches are well correlated at the end.This phenomenon-based parameter identification method may help facilitate precise prediction of complex jointed connection structures.展开更多
The distinct element method（DEM） incorporated with a novel bond contact model was applied in this paper to shed light on the microscopic physical origin of macroscopic behaviors of weathered rock, and to achieve the...The distinct element method（DEM） incorporated with a novel bond contact model was applied in this paper to shed light on the microscopic physical origin of macroscopic behaviors of weathered rock, and to achieve the changing laws of microscopic parameters from observed decaying properties of rocks during weathering. The changing laws of macroscopic mechanical properties of typical rocks were summarized based on the existing research achievements. Parametric simulations were then conducted to analyze the relationships between macroscopic and microscopic parameters, and to derive the changing laws of microscopic parameters for the DEM model. Equipped with the microscopic weathering laws, a series of DEM simulations of basic laboratory tests on weathered rock samples was performed in comparison with analytical solutions. The results reveal that the relationships between macroscopic and microscopic parameters of rocks against the weathering period can be successfully attained by parametric simulations. In addition, weathering has a significant impact on both stressestrain relationship and failure pattern of rocks.展开更多
A numerical model of thermoelectric module （TEM） is created by academic analysis,and the impacts of the resistance ratio and thermoelement size on the output power and thermoelectric efficiency of the TEM are analyz...A numerical model of thermoelectric module （TEM） is created by academic analysis,and the impacts of the resistance ratio and thermoelement size on the output power and thermoelectric efficiency of the TEM are analyzed by the MATLAB numerical calculation.The numerical model is validated by the ANSYS thermal,electrical,and structural coupling simulation.The effects of the variable physical property parameters and contact effect on the output power and thermoelectric efficiency are evaluated,and the concept of aspect ratio optimal domain is proposed,which provides a new design approach for the TEM.展开更多
The adhesion between the mining machine and the deep-sea sediments will significantly affect the driving performance of the mining machine in the deep-sea environment.When the mining machine and the deep-sea sediment ...The adhesion between the mining machine and the deep-sea sediments will significantly affect the driving performance of the mining machine in the deep-sea environment.When the mining machine and the deep-sea sediment interaction simulation was carried out,the accuracy of the particle interaction parameters will directly affect the simulation results.This study proposed a method to systematically calibrate the interaction parameters between deep-sea sediment and grouser through the combination of experiment and simulation.The uniaxial compression test and macro adhesion test and corresponding discrete element numerical simulation were carried out,modifying the contact parameters until the simulation results are close to the experimental results.Then the micro-parameters of the JKR adhesion contact model were back calibrated with the test results,and the contact parameters between soil particle-soil particle and soil particle-metal are calibrated.Besides,the adhesion test shows that the adhesion forces were ranked in the order of 5052<STi80<TA2<TC4 under the same surface roughness,which indicates the aluminum alloy 5052 has the best anti-adhesion performance.The relationship between surface adhesion force and microscopic contact parameters was studied by discrete element numerical simulation,and the result shows that the coefficient of static friction and the coefficient of rolling friction has little effect on adhesion force.While it is mainly affected by the coefficient of restitution and surface energy,the surface adhesion force tends to decrease with the increase of the coefficient of restitution and increase with the growth of surface energy.The obtained parameters of soil particle to soil particle and soil particle to metal affecting the adhesion can contribute to the design optimization for the grouser of mining machines to decrease surface adhesion and enhance its movability and mining efficiency.展开更多
Quinoa is an ancient crop that is nutritious,balanced,and suitable for most people.However,it has not been known and sought by the public until modern times.In recent years,quinoa has been intensively known and widely...Quinoa is an ancient crop that is nutritious,balanced,and suitable for most people.However,it has not been known and sought by the public until modern times.In recent years,quinoa has been intensively known and widely grown in China.Quinoa mechanized production machines have also been developed.With the help of DEM,we design and optimize the quinoa combined seeder,improving seeding efficiency and quality.In this paper,the basic physical and contact mechanics parameters required for the Hertz-Mindlin(no slip)of quinoa seeds in EDEM software were determined.The coefficient of rolling friction of quinoa seeds was calibrated on DEM,and which of Long Quinoa 4 is 0.043,and that of Meng Quinoa 4 was 0.016.Meanwhile,we can find that the coefficient of rolling friction strengthens the shape to restrict rolling and weakens the shape to increase rolling.The above research provides simulation parameters for the design and optimization of quinoa seed seeding machinery.展开更多
基金financially sponsored by the National Key Research and Development Program of China(Grant No.2022YFD2300100)Shandong Province Agricultural Major Technology Collaborative Extension Program Project(Grant No.SDNYXTTG-2024-15)the National Saline and Alkaline Land Comprehensive Utilization Technology Innovation Center Core Research Team Project(Grant No.NSALCUIC-2024).
文摘In this study,a simulation model of peanut pod particles during harvest in saline soil was tested to calibrate contact parameters.Discrete meta-fill models of peanut pods were generated by a 3D meter and EDEM software.The range of values of contact parameters for peanut pods was measured by conducting collision and other tests using a homemade test rig.The parameters that affect the significance of the simulation process of stacking angle were screened by the Plackett-Burman experiment,the steepest ascent experiment,and the Box-Behnken experiment.An optimization test determined the optimal simulation model parameters:The peanut pods had a Poisson’s ratio of 0.386 and a shear modulus of 3.04 MPa.The coefficient of recovery for pods-pods collisions was 0.335,the coefficient of static friction was 0.854,and the coefficient of rolling friction was 0.346.The coefficient of recovery of collision between the pods-65Mn steel was 0.339,the coefficient of static friction was 0.589,and the coefficient of rolling friction was 0.159.The test results showed a relative error of 0.42%between the stacking angle bench and simulation tests.The results can provide data support for studying the discrete metamaterial characterization of peanut pods.
基金support to Mr Malone in the form of CASE studentship [GR/P03711/01].
文摘Both linear-spring-dashpot （LSD） and non-linear Hertzian-spring-dashpot （HSD） contact models are commonly used for the calculation of contact forces in Discrete Element Method （DEM） simulations of granular systems. Despite the popularity of these models, determination of suitable values for the contact parameters of the simulated particles such as stiffness, damping coefficient, coefficient of restitution, and simulation time step, is not altogether obvious. In this work the relationships between these contact parameters for a model system where a particle impacts on a flat base are examined. Recommendations are made concerning the determination of these contact parameters for use in DEM simulations.
基金The authors acknowledge that this work was financially supported by the National Natural Science Foundation of China(Grant No.31901408)the Natural Science Foundation of Heilongjiang Province(Grant No.LH2020E097)+2 种基金the Science and Technology Development Project of Jilin Province(Grant No.20200402100NC20200201206JC)2020 China Russia Young Scientists Communication Project.
文摘Discrete element method was used to study and analyze the interaction between rice straws and between rice straw and agricultural machinery parts,thereby providing a scientific basis for post-harvest paddy field processing.Calibrations of rice straw-rice straw,rice straw-agricultural machinery part contact parameters(collision recovery coefficient,static friction coefficient and rolling friction coefficient)constitute an important prerequisite for the discrete element research process.In this study,the collision recovery coefficients of rice straw-steel and rice straw-rice straw were 0.230 and 0.357,respectively,which were calibrated by the collision method.The static friction coefficient and rolling friction coefficient of rice straw-steel were 0.363 and 0.208 respectively,which were calibrated by the inclined plate method and the slope method.The static friction coefficient and rolling friction coefficient of rice straw-rice straw were 0.44 and 0.07,respectively,which were calibrated by the split cylinder method.The paired t-test showed insignificant differences between calibration parameter simulation results and the physical test values(p>0.05).Taking the angle of repose that reflecting rice straw flow and friction characteristics as the evaluation index,the verification tests of the above calibration values indicated that the simulated angle of repose has no significant difference from the physical test value(p>0.05).The side plate lifting test on rice straw of different lengths showed no significant difference between the simulated angle of repose and the physical test value(p>0.05).This study can provide a basis for contact parameters choice in discrete element simulation analysis with rice straw-rice straw and rice straw-agricultural machinery parts as the research object.The calibration method can provide a reference for the contact parameter calibration of other crop straws.
基金financially supported by the Less Developed Regions of the National Natural Science Foundation of China(Grant No.52065058)the Graduate Education Innovation Project of Xinjiang Uygur Autonomous Region(Grant No.XJ2022G085)+1 种基金the Open Fund of Jiangsu Province and Education Ministry Co-sponsored Synergistic Innovation Center of Modern Agricultural Equipment,(Grant No.XTCX2006)the key industry innovation development support plan of southern Xinjiang(Grant No.2020DB008).
文摘In view of the fact that the existing cotton stem simulation models are simplified and have a large discrepancy from the actual appearance and the contact parameters have not been calibrated.In this study,the simulation model and numerical simulation were established using the discrete element software EDEM.Then a second-order response model between contact parameters and repose angle had been constructed.The test result showed that the static friction coefficient,rolling friction coefficient,and coefficient of restitution between cotton stems were crucial factors affecting the repose angle.The determination coefficient corrected determination coefficient and p-value of the second-order response model were R^(2)=0.959,R^(2)_(adj)=0.921,and p<0.0001 respectively.The error values of the comparison between the simulation test results and the corresponding physical test values were all less than 10%,which showed that the model was reliable and had high interpretation and predictability,this study can provide a certain theoretical basis and data support for the setting of contact parameters in the data simulation of cotton stem harvesting and processing,mechanically-harvested film residue crushing and film stem separation,etc.
基金Supported by National Defense Pre-Research Foundation of China(104010205)
文摘In order to identify the uncertain parameters of a bolted joint finite element model,a simple and applicable way of parameter identification is introduced.By utilizing numerical simulation with the Abaqus software and experimental investigation with the MTS material testing system,the tangential force-displacement curves that reflect the characteristics of the bolted joint were acquired.On the basis of this,by employing the response surface methodology（RSM）and genetic algorithms（GAs）,parameters in the FEM model were identified.The force-displacement curves by both virtual and experimental approaches are well correlated at the end.This phenomenon-based parameter identification method may help facilitate precise prediction of complex jointed connection structures.
基金funded by the National Basic Research Programs of China(Grant Nos.2011CB013504 and 2014CB046901)the National Funds for Distinguished Young Scientists of China(Grant No.51025932)the National Nature Science Foundation of China(Grant No.41372272)
文摘The distinct element method（DEM） incorporated with a novel bond contact model was applied in this paper to shed light on the microscopic physical origin of macroscopic behaviors of weathered rock, and to achieve the changing laws of microscopic parameters from observed decaying properties of rocks during weathering. The changing laws of macroscopic mechanical properties of typical rocks were summarized based on the existing research achievements. Parametric simulations were then conducted to analyze the relationships between macroscopic and microscopic parameters, and to derive the changing laws of microscopic parameters for the DEM model. Equipped with the microscopic weathering laws, a series of DEM simulations of basic laboratory tests on weathered rock samples was performed in comparison with analytical solutions. The results reveal that the relationships between macroscopic and microscopic parameters of rocks against the weathering period can be successfully attained by parametric simulations. In addition, weathering has a significant impact on both stressestrain relationship and failure pattern of rocks.
基金Funded by Guangdong Natural Science Foundation (No.00355991220615019)
文摘A numerical model of thermoelectric module （TEM） is created by academic analysis,and the impacts of the resistance ratio and thermoelement size on the output power and thermoelectric efficiency of the TEM are analyzed by the MATLAB numerical calculation.The numerical model is validated by the ANSYS thermal,electrical,and structural coupling simulation.The effects of the variable physical property parameters and contact effect on the output power and thermoelectric efficiency are evaluated,and the concept of aspect ratio optimal domain is proposed,which provides a new design approach for the TEM.
基金Project(12072309)supported by the National Natural Science Foundation of ChinaProject(19B546)supported by the Education Department Foundation of Hunan Province,ChinaProject(2019RS1059)supported by the Hunan Innovative Province Construction Project,China。
文摘The adhesion between the mining machine and the deep-sea sediments will significantly affect the driving performance of the mining machine in the deep-sea environment.When the mining machine and the deep-sea sediment interaction simulation was carried out,the accuracy of the particle interaction parameters will directly affect the simulation results.This study proposed a method to systematically calibrate the interaction parameters between deep-sea sediment and grouser through the combination of experiment and simulation.The uniaxial compression test and macro adhesion test and corresponding discrete element numerical simulation were carried out,modifying the contact parameters until the simulation results are close to the experimental results.Then the micro-parameters of the JKR adhesion contact model were back calibrated with the test results,and the contact parameters between soil particle-soil particle and soil particle-metal are calibrated.Besides,the adhesion test shows that the adhesion forces were ranked in the order of 5052<STi80<TA2<TC4 under the same surface roughness,which indicates the aluminum alloy 5052 has the best anti-adhesion performance.The relationship between surface adhesion force and microscopic contact parameters was studied by discrete element numerical simulation,and the result shows that the coefficient of static friction and the coefficient of rolling friction has little effect on adhesion force.While it is mainly affected by the coefficient of restitution and surface energy,the surface adhesion force tends to decrease with the increase of the coefficient of restitution and increase with the growth of surface energy.The obtained parameters of soil particle to soil particle and soil particle to metal affecting the adhesion can contribute to the design optimization for the grouser of mining machines to decrease surface adhesion and enhance its movability and mining efficiency.
基金supported by China Agriculture Research System of MOF and MARA(Grant No.CARS-14-1-28)Gansu Province Agricultural Science and Technology Innovation Project(Grant No.2021GAAS23)the National Natural Science Foundation of China grant number(Grant No.52065004,52365030).
文摘Quinoa is an ancient crop that is nutritious,balanced,and suitable for most people.However,it has not been known and sought by the public until modern times.In recent years,quinoa has been intensively known and widely grown in China.Quinoa mechanized production machines have also been developed.With the help of DEM,we design and optimize the quinoa combined seeder,improving seeding efficiency and quality.In this paper,the basic physical and contact mechanics parameters required for the Hertz-Mindlin(no slip)of quinoa seeds in EDEM software were determined.The coefficient of rolling friction of quinoa seeds was calibrated on DEM,and which of Long Quinoa 4 is 0.043,and that of Meng Quinoa 4 was 0.016.Meanwhile,we can find that the coefficient of rolling friction strengthens the shape to restrict rolling and weakens the shape to increase rolling.The above research provides simulation parameters for the design and optimization of quinoa seed seeding machinery.
