Correlation of microscopic and macroscopic characteristics of granular materials based on a rolling resistance linear model

Wang, Y. T.; Sun, Ruohan; Xu, Zhiwu

doi:10.1108/ec-09-2022-0590

Cited by 3 publications

References 18 publications

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The impact of the fine-grained parameters of the anti-rotation model on the macroscopic mechanical properties of Fujian standard sand

Liu,

Ding,

Zhang

et al. 2024

Preprint

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Based on PFC3D software, the mechanical response of model meso parameters to macro parameters of the Fujian sand triaxial test was analyzed. Combined with the results of indoor tests, the range of model parameters was determined. The simulation was conducted under the confining pressures of 100kpa, 300kpa and 500kpa respectively. After the macro parameters were obtained, the influence degree of each micro parameter on the macro parameters was analyzed through orthogonal test design to conduct sensitivity analysis on the contact modulus, stiffness ratio, friction coefficient, and anti-rotation coefficient of the sample. The results show that the elastic modulus is positively correlated with the contact modulus, friction coefficient, and anti-rotation coefficient, and negatively correlated with the stiffness ratio. The peak friction angle is negatively correlated with the contact modulus and stiffness ratio and positively correlated with the friction coefficient and anti-rotation coefficient. With the increase of the contact modulus and friction coefficient, the strain softening degree of the sample will increase, and the stiffness ratio and anti-rotation coefficient have no obvious effect on the strain softening degree. The contact modulus has little influence on the stable value of the mechanical coordination number of the sample. In contrast, the friction coefficient, stiffness ratio, and anti-rotation coefficient have greatly influenced the stable value of the mechanical coordination number. Compared with the orthogonal test design, the contact modulus has the greatest impact on the elastic modulus, and the stiffness ratio has the least impact on the elastic modulus. The friction coefficient has the greatest effect on the peak friction angle, and the stiffness ratio has the least effect on the peak friction angle. Based on the orthogonal experimental design results, a set of parameters is obtained. Finally, the PFC calibration results of Fujian sand are obtained by comparing the experimental results obtained from the predicted microscopic parameters with the laboratory tests, which provides a reference for future discrete element simulation laboratory tests.

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The impact of the fine-grained parameters of the anti-rotation model on the macroscopic mechanical properties of Fujian standard sand

Liu,

Ding,

Zhang

et al. 2024

Preprint

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Performance of Monotonic Pile Penetration in Sand: Model Test and DEM Simulation

Feng,

Luo,

Dong

et al. 2024

Buildings

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By integrating laboratory tests and three-dimensional discrete element methods, this research extensively explores the macroscopic and microscopic mechanisms of static pile penetration in standard sand. Initially, the mesoscopic parameters of standard sand were established via flexible triaxial compression tests, and a three-dimensional discrete element model was created using the particle size magnification technique. The study results confirm the rationality of parameter selection and numerical modeling by comparing penetration resistance and displacement obtained from laboratory model tests and discrete element simulations. Initially, penetration resistance swiftly increases, then stabilizes progressively with increasing depth. The lateral friction resistance grows with penetration depth, especially peaking near the cone tip. Moreover, horizontal stress quickly rises during pile penetration, mainly caused by the pile foundation compressing the adjacent soil particles. Displacement of the foundation particles is primarily focused around the pile side and cone tip, affecting an area roughly twice the pile diameter. Soil particle displacement exhibits a pronounced vertical downward movement, primarily driven by lateral friction. The distribution of force chains among foundation particles indicates that the primary stressed areas are at the pile ends, highlighting stress concentration features. This research offers significant insights into the mechanical behaviors and soil responses during pile foundation penetration.

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Contact force calculation and evolution analysis of granular systems based on micro-CT experiment

Wang,

Song,

Ping

et al. 2025

Acta Phys. Sin.

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The calculation of inter- granule contact force in three-dimensional granular systems is a critical and challenging aspect of granular mechanics research. Taking two elastic rubber balls as research object, in-situ flat pressing of Micro-CT experiment is carried out. Based on the Hertzian contact theory and Tatara large deformation contact theory, the contact model of elastic balls is verified, and the theoretical formula of the contact force of elastic balls based on the experiment is obtained. Taking the three-dimensional granular systems as research object, in-situ probe loading experiment of Micro-CT is carried out to obtain the two-dimensional image sequence of the granules, after a series of digital transformations, the digital body images are emerged, the contact force network of the three-dimensional granular systems under different loading states are obtained by constructing pore network models. The contact force distribution and evolution law of the granular systems are analyzed. The connection between the number of strong contacts and the distribution evolution and the stability of the granular systems is explored. The results show that the two elastic ball contact model conforms to the Hertzian contact theory and Tatara large deformation contact theory, the contact force fitting formula based on experiment can characterize the contact force between two granules reasonably and effectively. The contact force of granules under probe loading shows a net-like distribution with the contact point of the indenter as the starting point, and is transmitted to the lower and the surrounding area step by step. The trend of average contact force is consistent with the number of contacts, obvious phase changes are showed, as the number of contacts increases, the frequency of particle intercompression rises, resulting in greater contact forces between granules, eventually stabilizing at approximately 10.5 N. The number of strong contacts accounts for 45% to 50% of the total number of contacts, and the distribution runs through the whole granular systems, supporting the network structure of the granular systems, larger values are concentrated below the indenter showing a forked distribution. During the loading process, an equilibrium point is established at z=14mm, where the number of strong contacts reaches the peak, the network structure of strong contact force is spread over the whole three-dimensional granular systems, establishing the main skeleton to withstand the external load, as loading continues, the overall values of the strong contact forces increase, and their distribution within the granular system becomes more uniform.

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Correlation of microscopic and macroscopic characteristics of granular materials based on a rolling resistance linear model

Cited by 3 publications

References 18 publications

The impact of the fine-grained parameters of the anti-rotation model on the macroscopic mechanical properties of Fujian standard sand

The impact of the fine-grained parameters of the anti-rotation model on the macroscopic mechanical properties of Fujian standard sand

Performance of Monotonic Pile Penetration in Sand: Model Test and DEM Simulation

Contact force calculation and evolution analysis of granular systems based on micro-CT experiment

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