EDEM Software Research Articles

A novel mechanical-laser collaborative intra-row weeding prototype: structural design and optimization, weeding knife simulation and laser weeding experiment.

The competition between intra-row weeds and cultivated vegetables for nutrients is a major contributor for crop yield reduction. Compared with manual weeding, intelligent robots can improve the efficiency of weeding operations. This study proposed a novel mechanical-laser collaborative intra-row weeding device structure. A slider-crank mechanism size optimization algorithm was proposed, and the correctness of the algorithm was verified by ADMAS software. Finally, the crank and link lengths were determined to be 87 mm and 135 mm, respectively. The resistance of triangular weeding knives with different penetration angles and edge angles in the soil was simulated and analyzed using EDEM software. The simulation results show that the triangular weeding knife with a soil penetration angle of 0 ° and an edge angle of 30 ° encountered the least resistance. In addition, weed control experiments with different powers and lasers were conducted using 200 W NIR and 200 W blue lasers. The experimental results show that the time it took for a 50 W blue laser and a 100 W NIR laser to remove small weeds was approximately between 0.3 and 0.4 s, and the time it took for a 50 W blue laser to remove larger weeds was approximately between 0.5 and 0.6 s. The time it took for 75 W and 50 W NIR lasers to remove weeds was more than 1 s. Based on the above research results, a prototype of a mechanical-laser collaborative intra-row weeding device was successfully built. This study provides a new idea for the field of intelligent weeding. The simulation and experimental results can provide a reference for the research and development of mechanical weeding and laser weeding equipment.

Design and Testing of Key Components for a Multi-Stage Crushing Device for High-Moisture Corn Ears Based on the Discrete Element Method

To improve the crushing efficiency and crushing pass rate of high-moisture corn ears (HMCEs), a multi-stage crushing scheme is proposed in this paper. A two-stage crushing device for HMCEs is designed, and the ear crushing process is analyzed. Firstly, a simulation model for HMCEs was established in EDEM software (2018), and the accuracy of the model was verified by the shear test. Subsequently, single-factor simulation experiments were conducted, with the crushing rate serving as the evaluation index. The optimal working parameter ranges for the HMCE device were identified as a primary crushing roller speed of 1200–1600 revolutions per minute (r/min), a secondary crushing roller clearance of 1.5–2.5 mm, and a secondary crushing roller speed of 2750–3750 r/min. A Box–Behnken experiment was conducted to establish a multiple regression equation. With the objective of maximizing the qualified crushing pass rate, the optimal combination of parameters was revealed: a primary crushing roller speed of 1500 r/min, a secondary crushing roller clearance of 2.5 mm, and a secondary crushing roller speed of 3280 r/min. The pass rate of corn cob crushing in the simulation test was 98.2%. The physical tests, using the optimized parameter combination, yielded a qualified crushing rate of 97.5%, which deviates by 0.7% from the simulation results, satisfying the requirement of a qualified crushing rate exceeding 95%. The experimental outcomes validate the rationality of the proposed crushing scheme and the accuracy of the model, providing a theoretical foundation for subsequent research endeavors.

Design and Test of Potato Seedling Killing and Residual Film Recycling Integrated Machine

Plastic film mulching technology can effectively enhance crop yield and quality, and the use of mulch has been increasing in recent years; however, the problem of mulch residue is worsening due to the large amount of recycling work and slow natural degradation. In this study, a potato seedling killing and residual film recycling machine is designed to provide good working conditions for potato harvesters before harvesting in response to the problems of difficult separation of film tangles, the low net rate of recycling due to the mixing of residual film with soil, and the high soil content in residual film recycling operations in northwest China. The machine is based on the potato monoculture and double row planting mode in Gansu area. This paper puts forward the overall design scheme and carries out the theoretical analysis and parameter determination of the key components, such as the seedling killing device, the film surface cleaning device, the film unloading device, and so on. Using EDEM software to carry out the virtual simulation test and Design-Expert13 to analyze the test results, we determined the optimal working scheme for the machine, with a forward speed of 0.8 m/s, a film gap of 125 mm, and a spiral stirrer speed of 600 r/min. Based on a field test for verification, the test results show that the machine’s residual film recovery rate was 83.3%, the impurity rate was 3.8%, and the rate of injury to the potatoes was 1.4%. The machine meets the requirements of national and industry standards, and it can simultaneously realize straw crushing, film surface cleaning, residual film recycling, and hydraulic film unloading operations, with better operating results and while reaching the expected results. It can also provide a reference for the design and testing of a seeding and residual film recycling machine.

Seeded granulation process in twin-screw granulators: A DEM approach

Twin-screw granulation is a promising continuous manufacturing technique for producing granules with tailored properties. This study investigates the impact of screw configuration and speed on seeded granule formation using discrete element method (DEM) simulations. The aim is to identify optimal screw designs and operating conditions that yield desirable granule characteristics, such as high coordination, fine particle coverage, and throughput. DEM simulations were performed using Altair's EDEM software, employing Hertz-Mindlin and JKR contact models to capture particle-particle interactions and binder liquid effects. Five screw configurations (C1, C2, C3, C4, and CI) with varying conveying zone lengths and kneading elements were investigated, and screw speed was varied from 300 to 800 RPM. The Results show that screw configuration plays a crucial role in determining seeded granule characteristics. Increasing screw speed had a detrimental effect on granule properties, with lower speeds of 300 RPM yielding the granules with the greatest coordination number with the highest fine coverage. The study highlights the complex interplay between screw configuration, conveying zone length, kneading elements, and residence time in determining granule properties. Recommendations are provided for selecting suitable screw configurations and operating conditions for specific applications. Further research is suggested to investigate granule size distribution and morphology at different liquid properties screw speeds, and liquid-to-solid ratios.

Outer spiral drill rod lunar soil sampling resistance moment simulation study

Abstract The task of unmanned automated sampling of China’s lunar exploration is to bring back lunar soil samples with a certain depth, and sampling of external auger drill pipe is the best way. The power and moment size of the lunar surface is limited, so a special design is required. In this paper, a unique structural model of a double-auger drilling tool is designed. It is a movement analysis of lunar soil and drill pipe. We use simulated lunar soil simulations and experiments. The Hertz-Mindlin slip-free model in the discrete element software EDEM was used for numerical simulation. Given the disadvantage of the large amount of computation of discrete elements, the “embedding simulation method” proposed in this paper reduces the amount of computation. When drilling 0.4m and 1m under lunar and earth gravity, the magnitude and influence of drill pipe rotation and vertical velocity on the drag moment were analyzed. We provide the relevant technical parameters of the real unmanned drilling activities on the lunar surface. Through simulation, the rationality parameters of several groups of drill pipe drilling are obtained to ensure the smooth progress of drilling.

Analysis of structural parameters of stirred engineered composite robots in high-risk environments

Facing the safety of firefighting operators in high-risk environments, this paper investigates a robot for mixing engineering composites, which can automatically monitor the homogeneity of the mixing and, together with an automatic material feeding system, can realize automated production. This Study is based on the numerical simulation method that explored the discrete element model of engineering composites, carried out the multifactorial structural parameter orthogonal simulation experiment of the mixing robot in EDEM software, investigated the effects of different structural parameters on mixing time, mixing uniformity and productivity, proposed a mixing robot concrete uniformity intelligent identification algorithm.

Research on the Characterization of Bonding Parameters for Ore Particles Based on Response Surface Methodology

Ore is a crucial component in the process of industrialization, and its crushing is a practice that is inextricably linked to our society. This study aims to simulate the crushing process of minerals in a comminution device using the Discrete Element Method (DEM) by characterizing the bonding parameters of mineral particles. Utilizing the EDEM software (2018) for discrete element simulations, the study investigated the influence of bonding parameters on the compressive strength and other performance indicators of the particle bonding model. The study was executed through the application of a Box–Behnken Design (BBD) and Response Surface Methodology (RSM), which facilitated the construction of a second-order response surface regression model. The optimal values for normal stiffness per unit area, shear stiffness per unit area, critical normal stress, and critical shear stress were meticulously determined. The subsequent simulation experiments strongly verify the feasibility of the proposed characterization method for key parameters.

Development of a Bionic Picking Device for High Harvest and Low Loss Rate Pod Pepper Harvesting and Related Working Parameter Optimization Details

Addressing the issues of low harvesting efficiency and high losses in current pod pepper harvesters, this study presents the design of a bionic comb finger pod pepper picking device and an inclined double-spiral bell pepper harvester to improve the harvest rate and reduce loss rate. Through the utilization of discrete element simulation software EDEM, a discrete element model for pod peppers is established. Additionally, a simulation platform for ground drop loss during pod pepper picking is developed, enabling exploration of the movement trajectory and velocity changes of the pod pepper elements. The study also conducts an analysis on the impact of the speed of the picking rollers X1, the feeding speed of pod peppers X2, and the spacing between the two picking rollers X3 on ground drop losses. Based on the results of the single-factor test, the Box–Behnken response surface test was used to optimize the working parameters of the picking device, which resulted in the optimal combination of the working parameters of the picking device: the speed of the picking rollers was 680.41 rpm, the feeding speed of the pod peppers was 0.5 m/s, and the spacing between the two picking rollers was 12 mm, which resulted in the loss rate of pod peppers on the floor of the ground being 3.526%.

The Simulation and Parameter Optimization of the Hole-Forming Process of a Duckbilled Hole-Forming Device

This paper addresses the hole-forming process of a duckbilled hole-forming device. Based on a coupled simulation using the multi-body dynamics software RecurDyn and the discrete element software EDEM, the hole-forming mechanism of a duckbilled hole-forming device and the influence of control parameters on the hole-forming performance of the hole-forming device were studied. In this paper, we analyze the direction and speed of soil particles transported under soil disturbance by a hole-forming device through the simulation and study of the hole-forming mechanism of the hole-forming device. By controlling parameters such as the traction angle, forward speed, and mass of the hole-forming device, the influence of the control parameters on the hole-forming trajectory of the duckbilled hole-forming device was investigated. Orthogonal tests determined the optimal combination of control parameters. The results show that the hole-forming process of the hole-forming device mainly comprises squeezing and shearing the soil to form holes, and the hole-forming performance of the hole-forming device was optimal when the traction angle was 17.3°, the forward speed was 1.11 m/s, and the mass of the hole-forming device was 17.9 kg.

Research on the Population Flow and Mixing Characteristics of Pelleted Vegetable Seeds Based on the Bonded-Particle Model

In order to precisely reproduce the precise seeding process of the population in the air-suction seed-metering device, it is necessary to execute accurate modeling of seed particles using the bonded-particle model, in combination with the discrete element method (DEM) and computational fluid dynamics (CFD). Through the repose angle, slope screening, rotating container, and particle sedimentation experiments, in this paper, the influence of the filling accuracy of the bonded-particle model on the flow behavior and mixing characteristics of the seed population was first explored based on EDEM software. The viability of the suggested modeling approach for pelleted vegetable seeds, as described in this study, was confirmed by comparing experimental and simulation outcomes. The surface roughness values obtained from the studies above were utilized to assess the accuracy of the bonded-particle model in filling. Additionally, a mathematical technique for determining the surface roughness was provided. Furthermore, an analysis of the multiple contacts in the bonded-particle model was also performed. The results indicated that the simulation results closely matched the experimental data when the number of sub-spheres in the bonded-particle model was equal to or more than 70, as measured by the standard deviation. In addition, the most optimal modeling scheme for the pelletized vegetable seed bonded-particles, based on the cost of coupling simulation, was found to be the bonded-particle surface roughness (BS) with a value of 0.1. Ultimately, a practical example was utilized to demonstrate the utilization of the pelleted vegetable seed bonded-particle model and the DEM-CFD coupling approach in analyzing the accuracy of the seeding process in the air-suction seed-metering device. This example will serve as a valuable reference point for future field studies.

交叉导流式振动种箱设计与机理研究

Aiming at the existing rice mechanized seeding technology it is difficult to meet the hybrid rice low seeding volume precision seeding requirements. In this paper, based on the friction characteristics of rice seed and the theory of silo arching, the structure and parameters of seed filling room with staggered oriented plates and vibration in the quantitative seed supply device were designed. EDEM software was used to simulate the working process of the quantitative seed supply device, and it was determined that staggered oriented plates structure in the seed filling room combined with vibration could effectively prevent seed arching, thus improving the uniformity of seed supply. Finally, the results of the simulation analysis were verified by rice quantitative seed supply test. The results showed that the vibration could increase the seed supply frequency by 3.64% for large sowing weight of conventional rice and 5.52% for small sowing weight of hybrid rice. In addition, the analysis of the coefficient of variation of the seed supply frequency by quantitative seed supply devices showed that the vibration effect could increase the stability of seed supply device by 2.47 % for the conventional rice seed and 1.33 % for the hybrid rice seed, which increased the seed supply stability.

Parameter Optimization of a Conveying and Separating Device Based on a Five-Stage Screw and Vibrating Screen for Tiger Nut Harvesters

To tackle problems such as the difficult separation from sand and the high power consumption of tiger nut harvesting in the sandy areas of Xinjiang, a conveying and separating device for tiger nut harvesters was designed. The axial and radial migrations of materials under screw action and the separation process of materials under vibratory action were analyzed dynamically. A simulation analysis was carried out on the conveying and separating process based on EDEM software. The migration trajectories of tiger nuts and sand particles were extracted, the displacement variations of sand particles on the X-axis, Y-axis, and Z-axis were analyzed in the action area of the screen-cleaning spike teeth and the screw action area, respectively, and the conveying and separation law of the tiger nut harvest mixture was clarified. With key parameters such as the screw velocity ratio, amplitude, vibration frequency, and machine operation velocity as test factors, and with the sand removal rate, crushing rate, and power consumption as test evaluation indicators, a four-factor, five-level orthogonal central composite test design was implemented. The test results were analyzed via the regression variance analysis method, and relation models between variable factors and evaluation indicators were constructed. The test results show that under the combined conditions of a screw velocity ratio of 0.88, an amplitude of 4.7 mm, a vibration frequency of 7.5 Hz, and a machine operation velocity of 0.92 km/h, the sand removal rate is 90.40%, the crushing rate is 1.66%, and the power consumption is 2.24 kW in theory. The optimized results were verified by tests. The sand removal rate was 88.92%, the crushing rate was 1.71%, the total power consumption was 2.29 kW, and the errors from the predicted values were 1.6%, 3.0%, and 2.2%, respectively, meeting the requirements for tiger nut harvesting conveyance and separation. This research can provide support for the development of technology and equipment for mechanized harvesting of tiger nuts in the sandy areas of Xinjiang.

Research on the ditching resistance reduction of self-excited vibrations ditching device based on MBD-DEM coupling simulation.

In plant horticulture, furrow fertilizing is a common method to promote plant nutrient absorption and to effectively avoid fertilizer waste. Considering the high resistance caused by soil compaction in southern orchards, an energy-saving ditching device was proposed. A standard ditching blade with self-excited vibration device was designed, and operated in sandy clay with a tillage depth of 30cm. To conduct self-excited vibration ditching experiments, a simulation model of the interaction between soil and the ditching mechanism was established by coupling the ADAMS and EDEM software. To begin with, the ditching device model was first set up, taking into account its motion and morphological characteristics. Then, the MBD-DEM coupling method was employed to investigate the interaction mechanism and the effect of ditching between the soil particles and the ditching blade. Afterwards, the time-domain and frequency-domain characteristics of vibration signals during the ditching process were analyzed using the fast fourier transform (FFT) method, and the energy distribution characteristics were extracted using power spectral density (PSD). The experimental results revealed that the vibrations ditching device has reciprocating displacement in the Dx direction and torsional displacements in the θy and θz directions during operation, verifying the correctness of the coupling simulation and the effectiveness of vibrations ditching resistance reduction. Also, a load vibrations ditching bench test was conducted, and the results demonstrated that the self-excited vibrations ditching device, compared with common ditching device, achieved a reduction in ditching resistance of up to 12.3%. The reasonable parameters of spring stiffness, spring damping, and spring quality in self-excited vibrations ditching device can achieve a satisfied ditching performance with relatively low torque consumption at an appropriate speed.

Construction and parameter calibration of potato double‐layer flexible bonding model based on discrete‐element method

AbstractThe current discrete‐element simulation models for potatoes are multisphere polymer models derived from the Hertz–Mindlin (no slip) contact model in the discrete‐element simulation software (EDEM). These models oversimplify by considering potato peel and flesh as sharing identical mechanical properties within the structure. This oversimplification impedes a thorough investigation of the characteristics and mechanisms underlying potato peel‐breaking damage during mechanized harvesting, making in‐depth exploration challenging through simulation experiments. Consequently, this study conducted laboratory tests to determine the water content of potato peel and flesh, as well as the friction coefficients and collision recovery coefficients for various material pairs: flesh–steel, peel–steel, peel–peel, peel–flesh, and flesh–flesh. Subsequently, based on these findings, a double‐layer flexible bonding model for potato samples and whole stems under specific water content conditions was developed using EDEM software. The bonding parameters of the double‐layer flexible model for potato samples were refined through virtual shear calibration tests, leading to the identification of the optimal parameter combination: Flesh particle–flesh particle normal stiffness(tangential stiffness) per unit area X1 = 4.39 × 108 N/m3, peel particle–flesh particle normal stiffness(shear stiffness) per unit area X3 = 1.81 × 109 N/m3, peel particle–peel particle shear stiffness per unit area X6 = 1.99 × 109 N/m3, peel particle–peel particle critical normal stress X7 = 2.06 × 109 Pa. To validate the accuracy of the bonding parameters, shear and compression validation tests were conducted on entire potato stems. Comparison of the validation results from laboratory tests and simulation tests revealed an average relative error of e = 3.25%, signifying the feasibility of the constructed double‐layer flexible bond model for potatoes. This model meets the requirements for studying the characteristics and mechanisms of peel‐breaking damage in potatoes.Practical ApplicationsThe paper introduces a novel double‐layer flexible bonding model for potatoes using the discrete‐element method (DEM), which accurately simulates the mechanical properties and damage characteristics of potato peels and flesh. This research has significant practical applications in agricultural machinery design, improving the efficiency and reducing the damage during mechanical harvesting. By providing a more realistic simulation of potato behavior under mechanical stress, it can guide the development of gentler handling equipment, reduce waste, and enhance the quality of harvested potatoes. This contributes to optimizing the post‐harvest process, ensuring better storage, and extending the marketable life of potatoes.

小区小麦联合收获机割台清理离散元仿真参数标定

The analysis of the clearing process of the cutting deck of a small plot wheat combine harvester requires the use of discrete element simulation methods. However, the current simulation test lacks the contact parameters such as wheat stalk and stalk-seed. In this paper, the wheat stalks and seeds at harvest time were taken as the research objects, and the calibration study of the discrete element simulation model parameters of stalks and stalk-seeds was carried out by means of mechanical test determination and EDEM software simulation. The stiffness coefficients of wheat stalks were determined by mechanical tests; the average values of wheat stalk stacking angle of 39.22° and wheat stalk-seed stacking angle of 44.41° were obtained by stacking angle tests. By the steepest climb test and binary regression test, the stalk normal stiffness coefficient was determined to be 5e+08N/m2 and tangential stiffness was determined to be 6.35e+08N/m2; the stalk-stalk collision recovery coefficient was obtained to be 0.551, static friction coefficient was obtained to be 0.797, and rolling friction coefficient was obtained to be 0.079 by the two-level analytical factorization test, the steepest climb test, and the three-factor response surface test. Based on this, the average value of wheat stalk-seed stacking angle was obtained to be 39.22° and the average value of wheat stalk-seed stacking angle was obtained to be 44.41° by the stacking angle test. On this basis, the coefficient of recovery of stalk-stalk collision was 0.434, the coefficient of static friction was 0.884, and the coefficient of rolling friction was 0.339 obtained by the three-factor response surface test. Three validation experiments were carried out by substituting the obtained parameters into the simulation test, and the error values were close to the error value %0.255 in the model, which proved that the experimental data were reliable.

基于EDEM软件的气压式精量排种器充种性能模拟与试验

In order to study the effect of population disturbance on the filling performance of the seed metering device, this paper uses the pneumatic precision seed metering device as the model, and uses EDEM software to simulate the population movement of three different seed metering devices. The bench test was carried out at different pressures at 12 km/h and at different speeds at 3.5 kPa. The results show that the designed seed disk with grooves has the most intense disturbance and the highest qualified rate. In order to verify the performance of the disk, full factor tests are carried out on the air pressure and speed, The test results show that when the operating speed is 10~12 km/h and the positive pressure is 3~3.5 kPa, the leakage rate is no higher than 5.42%, the replay rate is no higher than 0.42%, and the qualified rate is no lower than 94.58%. When the operating speed is 14 ~ 16 km/h and the positive pressure is 3.5~4 kPa, the leakage rate is not higher than 6.7%, the replay rate is not higher than 1.04%, and the pass rate is not lower than 93.12%. All the indicators are better than the national standard.

Design and Experiment of Oil-Electric Hybrid Air-Suction Sorghum Plot Seeder

To tackle the issues of low seeding accuracy and seed injury caused by the seeders utilized at a small scale and in the plot seeding of sorghum in mountainous or hilly regions, this study presents the design of an oil–electric hybrid air suction sorghum plot seeder. The main working parts of the seeder are described, and the performance of the seed-mixing device is simulated using EDEM software. An oil–electric hybrid drive mode is used to provide power for operation and to the seed-metering device and fan. Additionally, a sowing control and monitoring system is designed using a single-chip microcomputer controller to ensure uniform plant spacing at different forward speeds. A multi-factor experiment is conducted using the central synthesis method to determine the optimal operating parameters of the seed-metering device through bench tests. The results show that a profile hole diameter of 2.5 mm on the seed tray, a negative-pressure chamber vacuum of 8.0 kPa, and a seed-metering device speed of 28 r/min result in a 95.95% pass rate, 0.5% missing rate, and 3.55% reseeding rate. The deviation between the experimental and analytical results that validate the optimum parameters is kept within acceptable limits. Field tests are conducted at different forward speeds using the optimum parameter combinations, and a comparison is made with the widely used duckbill planter. The results show pass, missing, and reseeding rates of 94.41%, 2.3%, and 3.29%, respectively. The missing monitoring error is less than 7.19%. All of the indices of the oil–electric hybrid air suction sorghum plot seeder are superior to those of the duckbill planter; thus, it fulfills the agronomic requirements for seeding a sorghum plot.

Enhancement of Wear Resistance of High-Load Pressing Screw in Smokeless Charcoal Production by Using Genetic Algorithm and Discrete Element Method

During the production of smokeless charcoal, the pressing screw of the sawdust compressor is exposed to the effects of friction and elevated temperature, resulting in rapid wear. This phenomenon not only diminishes productivity but also exerts adverse influences on the final product's quality. Consequently, the pursuit of research endeavors aiming at prolonging the lifespan of the pressing screw holds significant importance, not only in reducing production costs but also in enhancing the product's overall quality. This paper adopts an innovative approach by integrating theoretical calculations, numerical simulations with practical experiments to ascertain the optimal profile for the pressing screw. This methodology employs Genetic Algorithm and Discrete Element Method (DEM) simulations in conjunction with the EDEM software to simulate the working process and provide the optimal profile of the pressing screw. The analysis and simulation results indicate a substantial enhancement in the wear resistance of the pressing screw while ensuring the efficient movement of discrete materials during the pressing process. The results of this study not only indicate the main wear locations on the pressing screw but also suggest the optimal profile, providing a basis and control for wear assessment. Furthermore, the results of this research not only identifies the principal areas that are susceptible to wear on the pressing screw but also proposes optimal profile, threreby establish a solid foundation and methodology for wear assessment. These results will be pragmatically implemented in smokeless charcoal production factories, concurrently pave the way for further research and applications in this field.

Effect of compaction degree on the topological characteristics of force chain network (FCN) in aggregate blend

Aggregates are the main carrier to resist external loads for asphalt pavement, and the characteristics of force chain network (FCN) in aggregate blend are closely related to the skeleton performance of asphalt mixture. This study analyzed the effect of compaction degree of aggregate blend on the topological characteristics of FCN using discrete element (DEM) and complex network theory. Six types of aggregate blends with different gradations were generated and compacted using DEM software EDEM. The compaction degree was evenly divided into 7 parts from the loose to the compacted states. FCN topology graph (FCNTG) of aggregate blend at each compaction degree was built according to the contact information between aggregates and the definition of complex network. The features of each FCNTG were quantified using the indicators characterizing complex network (including degree, vertex strength, clustering coefficient, and path length). The effect of compaction degree on the characteristics of FCN was analyzed. The results showed that complex network theory is a feasible method for investigating aggregate blend FCN. Each topological feature indicator in complex network method can be used to analyze the internal structural features of aggregate blend. With increasing compaction degree, the average degree and the average vertex strength of aggregate blend FCN and different size particles increase gradually, the clustering performance of particles becomes better gradually, and the average path length of FCN decreases gradually. There is a good linear relationship between the compaction degree and each topology indicator except the vertex strength. The compaction can reduce the dispersion degree of the contact forces between particles in aggregate blend and make it more uniform. It can also shorten the path length between two particles, which is important to improve the efficiency of transferring the external load.

Research on wear resistance of conical pick based on bionic dimple structure

Heavy equipment such as continuous mining machine and shearer are widely used in coal mining projects, and conical picks are essential cutting tools. The wear resistance of the conical picks directly affects the efficiency and reliability of the equipment. Additionally, when the conical pick cannot rotate properly, severe one-sided wear occurs and accelerates the failure of the conical pick. In this paper, a bionic dimple-structured conical pick is designed, and a mathematical model of the dimple structure is established. The self-rotation and wear resistance characteristics of the Dimple Type Pick (DTP) and the Ordinary Type Pick (OTP) are studied using the discrete element software EDEM and the dynamic analysis software ADAMS. The orthogonal experimental method is used to analyze the friction performance and mechanism of the conical pick surface from aspects such as dimple depth, number, and radius. The results show that the rotational torque of the two types of conical picks increases first and then decreases during the cutting process. The maximum torque of the DTP is 42.67% higher than that of the OTP, which indicates that DTP has better self-rotation performance than OTP. Dimple depth is the main factor affecting DTP wear, followed by the number of dimples, while the impact of dimple radius is minimal. According to the analysis on the response surface, the optimal design parameters of the dimple structure are as follows: the dimple depth is 0.3 mm, the number of dimples is 4, and the radius is 1.5 mm. The wear resistance of the optimized dimple-structured conical pick showed an improvement of 89.82% and 79.04%, compared to the OTP and the DTP. This research provides theoretical and experimental support for the development of wear-resistant and long-life conical picks.