Discrete Element Model Research Articles (Page 1)

Predicting the evolution of biomass bulk density through feedstock preprocessing: Discrete element modeling, regression analysis, and pilot-scale validation

A common-normal-based framework for efficient ellipse contact detection in discrete element modelling

Micro-mechanical characterization of polymer-modified asphalt mixtures using discrete element modelling with soft-bond and linear contact bond models

The loading rate of coal is significantly influenced by the number of vanes on shearer drums. However, in actual production, 1400 mm diameter drums feature two-vane and three-vane designs, while 2240 mm diameter ones have three-vane and four-vane designs, with the vane number corresponding to the optimal coal-loading rate remaining unclear. To reveal the correlation between vane number and coal-loading rate for such drums, parameters were calibrated through multiple physical tests in this study. Supported by field data, simulation analyses were conducted via the discrete element method to investigate the effect of the vane number on the drum coal-loading rate under different moisture contents and traction speeds. The results indicated that particle adhesion initially increases and then decreases with the moisture content, with the peak characteristics influenced by the particle size. Particle movement during drum coal mining is jointly governed by multiple factors. For 1400 mm drums, two or three vanes should be selected depending on moisture fluctuations and coal transportation requirements, whereas for 2240 mm drums, three or four vanes are recommended based on the balance between coal-cutting volume, conveying capacity, and traction speed.

The ballast consists of angular particles whose main function is to transmit and distribute train loads to the soil. However, under repeated loads, these particles wear down and break, causing permanent settlement, reducing track stability, and increasing maintenance. Characterizing stresses and deformations under monotonic and cyclic loading is essential to predict short- and long-term performance of railway systems. This numerical study evaluates the behavior of improved ballast materials, considering particle breakage. A hybrid Finite Difference and Discrete Element model was used to simulate the multiscale response of the track system under realistic loading conditions. The model was calibrated using data from laboratory tests conducted by various researchers. The performance of conventional ballast was compared with alternative mixtures, analyzing vertical displacements, stress distribution, safety factor, and particle breakage rates. Results show that the basalt-rubber composite significantly enhances ballast performance by reducing settlements and subgrade stresses while improving resistance to particle breakage. The FDM-DEM coupled approach effectively captures micromechanical interactions and breakage mechanisms, offering valuable insights for optimizing track design based on quantifiable performance criteria. Overall, the findings indicate the hybrid model and breakage–contact criteria approximated system behavior, while alternative ballast compositions improved durability, reduced maintenance, and supported resilient railway solutions.

Abstract This study presents a diffusion‐assisted particle reconstruction model (DPRM), a novel framework for reconstructing high‐fidelity 3D particle morphology from a single 2D image of granular assemblies. DPRM leverages cascaded large vision models in three stages: (1) segmentation of individual grains via a U‐Net‐enhanced segment anything model, (2) multi‐view synthesis for each particle using denoising diffusion probabilistic models (DDPMs), and (3) 3D geometry approximation via a DDPM‐assisted large reconstruction model, generating simulation‐ready mesh representations. After mesh decimation and size correction, the outputs are compatible with discrete element modeling and other physics‐based simulations. Quantitative validations confirm DPRM's accuracy in predicting particle size and shape distributions. Crucially, the developed method enables zero‐shot generation to novel scenarios without extensive retraining, overcoming limitations of prior methods. This work establishes the first end‐to‐end pipeline for particle‐level 3D reconstruction from monocular scene images, enabling the generation of statistically realistic particle shape for physics‐based granular simulations in engineering and industry.

This study develops a discrete element model incorporating the water–ice phase transition volume effect to simulate frost damage in saturated granite. The model investigates the damage evolution and mechanical degradation under freeze–thaw cycles. The results show that during freeze–thaw cycles, the model’s temperature field exhibits non-uniform distribution characteristics and geometric dependency, with lower maximum temperature differences in Brazilian disk models versus uniaxial compression specimens. Frost heave damage progresses through three distinct stages: localized bond fractures (1~5 cycles); accelerated crack interconnection and branching (15~20 cycles); and fully interconnected damage zones (25~30 cycles). As the number of freeze–thaw cycles increases, the crack network significantly influences the mechanical behavior of the model under load. The failure mode of the loaded model undergoes a transformation from brittle penetration to ductile fragmentation. Freeze–thaw cycles cause more significant degradation in the tensile strength of granite compared to compressive strength. After 30 freeze–thaw cycles, the uniaxial compressive strength and Brazilian tensile strength decrease by 47.5% and 93.8%, respectively. These findings provide theoretical support for assessing frost heave damage in geotechnical engineering in cold regions.

ABSTRACT In order to investigate the dynamic shear characteristics of rubber sand under cyclic loading, a series of cyclic torsional shear tests was conducted using a hollow cylinder torsional shear apparatus. The effects of four cyclic vertical stress ratios (CVSRs = 0.15, 0.25, 0.35, and 0.45) and four cyclic torsional stress ratios ( η = 0, 1/6, 1/3, and 1/2) on the strength and volumetric deformation characteristics of rubber sand were analyzed. Based on the tests, a three‐dimensional undrained discrete element model of a hollow cylinder torsional shear test was developed to further examine the evolution of particle motion, porosity, coordination number, and fabric anisotropy during the shearing process. The results show that with increasing cyclic vertical and torsional stress ratios, horizontal reconstruction of shear bands becomes more pronounced, and axial strain accumulates more rapidly. When CVSR and η are relatively small, the shear modulus decreases gradually with their increase, and the damping ratio remains relatively stable. At the mesoscopic level, the contact network exhibits a decrease in coordination number, a rapid increase in porosity, and an accelerated decay of normal contact force. When CVSR and η are relatively large, the particle skeleton undergoes rapid liquefaction and reorganization, with the shear modulus and damping ratio decreasing sharply. At this stage, the number of normal contacts is reduced to a minimum, and the normal contact force almost completely disappears.

A cylindrical grader is an important piece of equipment used to grade maize seeds. However, the motion and distribution patterns of seeds within the cylindrical grading process remain poorly understood, leading to a heavy reliance on empirical adjustments of operational parameters during grading. This results in issues such as low grading efficiency, unstable operational performance, and failure to meet practical production requirements. To investigate the motion and distribution patterns of maize seeds during cylindrical grading, key simulation parameters characterizing the maize seeds and grading cylinders were experimentally determined. Discrete element models of maize seeds and the grading cylinder were subsequently developed using EDEM 2018 software. Variations in seed motion velocity and the coefficient of variation (CV) along the circumferential and axial directions were analyzed under different operational parameters, including cylinder rotational speed, inclination angle, and feeding rate. Discrete element simulations combined with orthogonal experiments revealed that the order of influence of these factors on the grading qualification rate was as follows: inclination angle > rotational speed > feeding rate. The results of the interaction analysis showed that the interaction between the inclination angle and rotational speed significantly affected the grading qualification rate, while the interactions among the other factors had no significant effect. The optimized parameter combination was identified as a rotational speed of 47.08 r/min, an inclination angle of 0.52°‌, and a feeding rate of ‌303.07 g/s‌, achieving a theoretical grading qualification rate of 97.24%. Validation experiments conducted with this optimal combination yielded a practical grading qualification rate of ‌93.83%‌, with the relative error between the experimental and predicted values below 4%‌. These results confirm the validity of discrete element simulations for analyzing maize seed motion dynamics and provide a valuable reference for further research in this field.

This study investigates the microscale mechanisms underlying the compressibility of biochar-amended soils through combined discrete element method (DEM) simulations and laboratory consolidation tests. A three-dimensional discrete element model was established based on the MatDEM platform, accounting for the particle crushing process of biochar particles and its impact on soil mechanical properties. The biochar agglomerate particles generated in the simulation exhibit irregular morphology, and particles within different size ranges were selected for investigation. According to the model and experimental results, the average relative error is about 7%. Results demonstrate that moderate biochar content effectively reduces soil compressibility by enhancing load transfer through stable force chains formed by biochar particles, which exhibit larger contact areas and higher stiffness compared to native soil particles. However, when the biochar content exceeds approximately 40%, particle crushing intensifies, particularly under high initial void ratios, leading to increased soil compressibility. Furthermore, a larger initial void ratio weakens interparticle confinement, promotes microcrack propagation, and thereby exacerbates compressive deformation. Biochar fragmentation progresses through three stress-dependent stages: initial compaction (<100 kPa), skeletal damage (100–800 kPa), and crushing saturation (>800 kPa). Increased biochar particle size correlates with higher fragmentation rates, refined particle gradation, and reduced coordination numbers, collectively weakening the soil skeleton and promoting deformation. These findings underscore the importance of optimizing biochar content and applying graded loading strategies to balance enhanced soil performance with material integrity. These findings emphasize the necessity of optimizing biochar application rates to balance enhanced soil performance with resource efficiency, providing critical insights for sustainable geotechnical practices.

Soil desiccation cracks are common in farmland under dry conditions, which can alter soil water movement by providing preferential flow paths and thus affect water and fertilizer use efficiency. Understanding the mechanism of soil shrinkage and cracking is of great significance for optimizing field management by crack utilization or prevention. The behavior of soil shrinkage and cracking was monitored during drying experiments and analyzed with the help of a digital image processing method. The results showed that during shrinkage, the changes in soil height and equivalent diameter with water content differed significantly. The height change consisted of a rapid decline stage and a residual stage, while the equivalent diameter had a stable stage before the rapid decline stage. The VG-Peng model was suitable to fit the soil shrinkage characteristic curves, and the curves revealed that the soil shrinkage contained structural shrinkage, proportional shrinkage, residual shrinkage, and zero shrinkage stages. According to the changes in evaporation intensity, soil water evaporation could be divided into three stages: stable stage, declining stage, and residual stage. Cracks first formed in the defect areas and edge areas of the soil, and they mainly propagated in the stable evaporation stage. Crack development was dominated by an increase in crack length during the early cracking stage, while the propagation of crack width played a major role during the later stage. At the end of drying, the contribution ratio of crack length and width to the crack area was approximately 30% and 70%, respectively. The box-counting fractal dimension of the stabilized cracks was approximately 1.65, indicating that the crack network had significant self-similarity. The experimental results were used to implement the discrete element method to model the process of soil shrinkage and cracking. The models could effectively simulate the variation characteristics of soil height and equivalent diameter during shrinkage, as well as the variation characteristics of crack ratio and length density during cracking, with acceptable relative errors. In particular, the modeled morphology of the crack network was highly similar to the experimental observation. Our results provide new insights into the characterization and simulation of soil desiccation cracks, which will be conducive to understanding crack evolution and soil water movement in farmland.

Under diverse conditions, multiple empirical models are employed to forecast screen performance. Although they provide good insight for the sizing and selection of screens, they generally are insufficient for the precise quantification of the effects of parameters such as surface dimensions, aperture size, aperture shape/orientation and surface open area. Discrete element modelling has proved in many instances that it provides close-up examination of motion of particles under various conditions for a variety of mineral processing operations and provides data that is not possible to obtain with conventional experimentation or sampling. This study aims at investigating the influence of screen surface parameters (i.e. surface dimensions, aperture orientation/shape, aperture size and surface open area) on screening performance with the aid of Discrete Element Modelling (DEM) method for the simulation of vibrating screens. In order to achieve realistic simulations “multi-spheres” were used for the representation of particles with irregular shapes. The simulation results show that particle motions were accurately predicted and simulation data were evaluated using conventional screen efficiency criteria. The separation of particles was also investigated in terms of size distribution of products and residence time of particles along the screen.

Analysis of mixing liquid amendments by rotary tillage using discrete element modelling and digital image processing

Discrete element modeling of shear cell experiments with cohesive wooden spheres

Impact of unbound aggregate packing on the dense bituminous mix properties: Experimental and discrete element model investigation

Calibration and validation of a discrete element model for sand and fine grain soil for use in vehicle mobility applications

Abstract Acoustic nonreciprocity has received significant interest, particularly in the context of enabling logic devices. One way to break reciprocity is through strategic spatiotemporal modulation of a material's properties. In this work, we propose and analytically, computationally, and experimentally explore a concept comprised of a quasione-dimensional nonlinear system, where the shear stiffness depends on longitudinal strain, with the aim that nonreciprocity of transverse-rotational waves could be enabled by the simultaneous propagation of a longitudinal wave injected from the boundary. Such an approach should require less computational overhead in contrast to systems wherein spatiotemporal modulation is accomplished by active control distributed throughout the material, and potentially enable scaling to smaller system sizes and higher frequencies. While good agreement, showing significant nonreciprocity, is found between our analytical predictions and our reduced-order, discrete element model (DEM) simulations, our higher fidelity, finite element model (FEM) simulations and experiments do not show the same. We suggest this qualitative difference is due to mechanical instability of the chain, which is not present in either the DEM simulations or analytical model. While providing a theoretical proposal for an all-acoustic spatiotemporally modulated non-reciprocal system, this work also identifies a critical limitation, namely that of instability, which should be addressed in future related concepts.

Selecting a reasonable mesoscopic contact model and corresponding contact parameters is a key problem in discrete element simulation. In order to characterize the mesoscopic contact characteristics between particles in cohesive soil–rock mixture (CSRM), a set of laboratory consolidated and undrained triaxial tests were conducted on remolded samples of clay and CSRM collected in situ. Based on the experiments, 2D discrete element models of clay and CSRM were established, respectively. Considering the difference in the mechanical characteristics between soil particles and between soil and rock particles, different types of contact model were applied. The effects of the contact stiffness, bond strength, and friction coefficient between soil particles and between soil and rock particles on the stress–strain curves of both clay and CSRM numerical samples were sequentially studied by parameter sensitivity analysis. Results show that the contact stiffness and friction coefficient between soil particles affect the initial tangent modulus, the peak stress and the post-peak residual stress of the clay sample, while the bonding strength only affects its peak stress and residual stress. However, the mesoscopic contact parameters between soil and rock particles have little effect on the initial tangent modulus of CSRM sample but have a certain impact on the development of stress in the plastic stage, among which the influences of normal bonding strength and friction coefficient between soil and rock particles are more obvious. Finally, according to the comparison between the laboratory test results and the corresponding numerical simulation results in both clay and CSRM samples, mesoscopic contact parameters in CSRM were calibrated.

ABSTRACTParallel fractures are common in rock masses and significantly affect their stability. This study examines how fracture inclination influences dynamic fracture behavior using Brazilian tests with a split Hopkinson pressure bar, combined with high‐speed photography and digital image correlation. Specimens with varying inclinations were tested to analyze changes in peak load, energy dissipation, and failure modes. Discrete element modeling was used for quasi‐static comparison. Results show that, with increasing inclination, peak load and dissipated energy first decrease, then increase, with a transition near 45°. Tensile wing cracks initiate at fracture tips, shifting toward the center at higher angles. Fracture develops in two stages: primary cracks from stress concentration and secondary cracks from tensile accumulation or crack interaction. Failure mechanisms evolve from tension‐dominated at low inclinations to mixed tensile–shear mode at higher angles. These findings clarify failure transitions and provide insights for stability assessment and engineering design of fractured rock masses.

A rapid calibration method for the discrete element model of straw fodder particle mixtures based on the UVE-PLS-GD algorithm