Discrete element modeling of realistic particle shapes in stone-based mixtures through MATLAB-based imaging process

Liu, Yu; Zhou, Xiaodong; You, Zhanping; Yao, Shun; Gong, Fangyuan; Wang, Hainian

doi:10.1016/j.conbuildmat.2017.03.037

Cited by 94 publications

(23 citation statements)

References 19 publications

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“…is paper attempts to reach a balance between accuracy and efficiency through adopting as few spheres as possible to form an agglomerate so that enough number of agglomerates could be generated to constitute a numerical sample without requiring too long computational time and effort. Although an agglomerate with a very large number of spheres was more like rock or soil in terms of morphology [47], it is verified that agglomerates with a limited number of spheres were able to generate reasonable results [20,22,27,48,49]. As observed from Figure 2, asperity, angularity, and sharp edges are obvious characteristics of angular gravels, and those gravels could be categorized into two kinds: one was slender and another relatively more rounded.…”

Section: Introductionmentioning

confidence: 71%

Numerical Study on the Evolution of Agglomerate Breakage and Microstructure of Angular Gravel in Cyclic Soil‐Structure Interface Test

Yang

Zhao

Liu

2019

Advances in Civil Engineering

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The discrete element method (DEM) was used to study the behavior of crushable angular gravel in the cyclic soil-structure interface test. Two shapes of agglomerates were simulated by filling two scanned angular gravels with spheres connected by bonds that were given the shear and normal strength complying with Gaussian distribution to simulate random flaws. The proportion of these two shapes to constitute a numerical sample was named composite pattern. Good agreement in terms of macromechanical behavior between DEM simulation and laboratory test results has been attained. Agglomerate breakage is deeply influenced by the interface shearing behavior and mainly occurs on the interface and the space nearby. Graphs of interface after shearing are introduced to directly and clearly reflect microbehavior of breakage. The evolution of microstructure including anisotropies and coordination numbers is significantly influenced by normal stress and agglomerate breakage, and composite pattern determines the magnitudes of shear force anisotropy and coordination numbers. The evolution of contact orientation distribution is the forming cause of the “adjustment phase,” during which once the shearing direction changes, the values of contact normal anisotropy and normal force anisotropy will slump to their nadir and then rise back again.

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Section: Introductionmentioning

confidence: 71%

Numerical Study on the Evolution of Agglomerate Breakage and Microstructure of Angular Gravel in Cyclic Soil‐Structure Interface Test

Yang

Zhao

Liu

2019

Advances in Civil Engineering

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“…It should be noted that there is only one particle shape in each specimen to amplify its effect, as shown in Figure 12. A total number of 15 DEM models with different real aggregated shapes were built based on previous researches [33][34][35][36][37]. It should be noted that there is only one particle shape in each specimen to amplify its effect, as shown in Figure 12.…”

Section: Reduction Factor Analysis Considering Particle Shape Effect mentioning

confidence: 99%

Porosity Prediction of Granular Materials through Discrete Element Method and Back Propagation Neural Network Algorithm

Liu

et al. 2020

Applied Sciences

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Granular materials are used directly or as the primary ingredients of the mixtures in industrial manufacturing, agricultural production and civil engineering. It has been a challenging task to compute the porosity of a granular material which contains a wide range of particle sizes or shapes. Against this background, this paper presents a newly developed method for the porosity prediction of granular materials through Discrete Element Modeling (DEM) and the Back Propagation Neural Network algorithm (BPNN). In DEM, ball elements were used to simulate particles in granular materials. According to the Chinese specifications, a total of 400 specimens in different gradations were built and compacted under the static pressure of 600 kPa. The porosity values of those specimens were recorded and applied to train the BPNN model. The primary parameters of the BPNN model were recommended for predicting the porosity of a granular material. Verification was performed by a self-designed experimental test and it was found that the prediction accuracy could reach 98%. Meanwhile, considering the influence of particle shape, a shape reduction factor was proposed to achieve the porosity reduction from sphere to real particle shape.

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“…Therefore, the mechanical behavior and motion state of each asphalt mixture particle may be analyzed according to Newton's second law [23,24]. Liu et al developed a simulation of realistic particle shapes in mixtures through a MATLAB-based imaging process and PFC-based FISH codes [25]. Li et al carried out an indirect tensile fatigue test of asphalt mixtures simulated with an image-based discrete element model [26].…”

Section: Introductionmentioning

confidence: 99%

“…Because bond failure will not occur in an actual situation, the tensile strength and shear strength in this linear contact bond model were set to a larger value [25]. The calculation results of the normal stiffness and tangential stiffness are shown in Table 9.…”

mentioning

confidence: 99%

Investigation on the Micro Deformation Mechanism of Asphalt Mixtures under High Temperatures Based on a Self-Developed Laboratory Test

Guo

Meng

et al. 2020

Materials

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Rutting has always been considered the main disease in asphalt pavement. Dealing with rutting disease would be benefitted by understanding the formation of rutting and testing the rutting performance of mixtures more reasonably. The objective of this paper is to systematically investigate the rutting mechanism by employing a self-designed rutting tester along with the corresponding numerical simulations. The deformation of different positions of the existing tracking tester was found to be inconsistent, and the loading was not in line with reality. Accordingly, a more practical tester was proposed: the reduced scale circular tracking (RSCT) tester integrates the functions of asphalt mixture fabrication and rutting monitoring. The results demonstrated that the loading of the new tester is closer to the actual situation. In addition, determining the stress and displacement characteristics of particles in the asphalt mixture was found to be difficult due to the limitations of the testing methods. Therefore, a two-dimensional virtual rutting test based on the RSCT was built using PFC2D (Particle Flow Code 2 Dimension) to investigate the mechanism of formation in rutting and to obtain the corresponding guidance. The numerical simulation showed that all particles of the specimen tended to move away from the load location. The main cause of rutting formation was the eddy current flow of asphalt mastic driven by coarse aggregates. The aggregates with diameters ranging from 9.5 to 4.75 mm were observed to have the greatest contribution to rutting deformation. Therefore, the aggregate amount of these spans should be focused on in the design of mixture grading.

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Discrete element modeling of realistic particle shapes in stone-based mixtures through MATLAB-based imaging process

Cited by 94 publications

References 19 publications

Numerical Study on the Evolution of Agglomerate Breakage and Microstructure of Angular Gravel in Cyclic Soil‐Structure Interface Test

Numerical Study on the Evolution of Agglomerate Breakage and Microstructure of Angular Gravel in Cyclic Soil‐Structure Interface Test

Porosity Prediction of Granular Materials through Discrete Element Method and Back Propagation Neural Network Algorithm

Investigation on the Micro Deformation Mechanism of Asphalt Mixtures under High Temperatures Based on a Self-Developed Laboratory Test

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