Article
Engineering, Geological
Tongming Qu, Min Wang, Yuntian Feng
Summary: This study compares DEM simulations with experimental granular materials in terms of deviatoric stress, volumetric behavior, critical state behavior, stress-dilatancy relationship, and the evolution of principal stress ratio against axial strain. The results show that DEM with spherical or clumped particles can qualitatively describe some macroscopic features of granular materials, but there are qualitative deviations in terms of stress-dilatancy behavior and principal stress ratio, which are critical for constitutive modeling.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2022)
Article
Engineering, Marine
JiaZhao Sun, Li Zou, Nicolin Govender, Ivan Martinez-Estevez, Alejandro J. C. Crespo, Zhe Sun, Jose M. Dominguez
Summary: This study proposes a three-dimensional resolved numerical framework for analyzing complex shape polyhedron-fluid interaction. It accurately simulates the dynamic behavior of hybrid fluid-particle systems using the weakly compressible smoothed particle hydrodynamics (SPH) and discrete element method (DEM). The high-fidelity modeling and efficient coupling scheme demonstrate the reliability and applicability of the SPH-DEM solver in various engineering problems.
Article
Mathematics, Interdisciplinary Applications
Peter Adesina, Catherine O'Sullivan, Teng Wang
Summary: This study examines the impact of particle convexity, sphericity, and aspect ratio on the behavior of sheared granular materials. Two-dimensional discrete element method simulations were used to investigate the macroscopic characteristics, such as strength and dilatancy, of isotropic, dense, and loose assemblies with different particle shapes. The results show that shear strength decreases with increasing particle convexity and sphericity, but increases with higher aspect ratio. The coordination number, fabric anisotropy, particle moment, friction mobilization at contacts, and particle rotation are identified as important factors underlying the macroscopic behavior.
COMPUTATIONAL PARTICLE MECHANICS
(2023)
Article
Engineering, Multidisciplinary
John M. Harmon, Konstantinos Karapiperis, Liuchi Li, Scott Moreland, Jose E. Andrade
Summary: This paper introduces the methodology of using the bonded particle method (BPM) with the level set discrete element method (LS-DEM-BPM) to model connected granular materials with arbitrary particle shape. Several examples are presented to demonstrate the method's application in different contexts, showing its potential predictive ability and insights into micromechanics. Additionally, advantages and disadvantages of the method are discussed.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2021)
Article
Engineering, Mechanical
Chao-Fa Zhao, Niels P. Kruyt
Summary: The study compares the rotational behavior of granular materials at the particle level to the continuum level, finding that the average particle rotation closely matches the continuum rotation. X-ray tomography of granular soil under triaxial compression further supports this observation. The presence of contact couples is found to have a significant effect on stress ratios and volumetric strain in simulations. Stress tensors remain symmetric even with the inclusion of contact couples.
JOURNAL OF ENGINEERING MECHANICS
(2021)
Article
Computer Science, Interdisciplinary Applications
Dechun Lu, Hongyu Dong, Qingtao Lin, Caixia Guo, Zhiwei Gao, Xiuli Du
Summary: The failure location of granular materials can be determined by capturing the deformation localization using a new concept called relative particle motion (RPM). An approach is developed to select particles for calculating RPM, controlled by two key parameters U (grid spacing) and R (domain radius). The proposed method is implemented in PFC2D and validated under different loading conditions, showing good agreement with the shear band observed in published literature.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Deze Yang, Xihua Chu
Summary: Creep and stress relaxation behaviors in granular materials are influenced by the time-dependent changes in their microstructure, with particle shape playing a significant role. However, the effects of particle shape on these behaviors are still not well understood. In this study, 3D DEM models incorporating the rate process theory and superellipsoids are used to simulate creep and stress relaxation in granular samples with different aspect ratios and blockiness. The results show that both aspect ratio and blockiness have a significant influence on creep and stress relaxation, with aspect ratio affecting creep through contact force ratio and blockiness affecting stress relaxation through variation in normal contact force anisotropy. These findings provide insights into the effects of particle shape on creep and stress relaxation in granular assemblies.
COMPUTERS AND GEOTECHNICS
(2024)
Article
Engineering, Chemical
Chuanfeng Fang, Jian Gong, Mingtao Jia, Zhihong Nie, Bo Li, Ashiru Mohammed, Lianheng Zhao
Summary: This report investigated the effect of angularity on the mechanical behavior of breakable granular materials, finding that as angularity increases, peak shear strength and extent of particle breakage exhibit a linear relationship.
ADVANCED POWDER TECHNOLOGY
(2021)
Article
Physics, Fluids & Plasmas
Meng Liu, Christoph R. Muller
Summary: The lift force model for intruders in dense, granular shear flows takes into account granular temperature, pressure differences, and density differences between the intruder and the bed particles. The model accurately predicts and explains the behavior of intruders in shear flows.
Article
Engineering, Chemical
Uyen Thi Hoang, Nhu H. T. Nguyen
Summary: This study systematically investigates the effects of particle shape on granular collapse using superquadric Discrete Element Method. The simulations include various particle shapes ranging from spheres to elongated/platy cubes. The results show that particles with higher blockiness exhibit shorter runout distance, increased retained height, and more stacking along boundary walls. Particle blockiness also affects the critical column aspect ratio and scaling law constants. Elongated and platy particles cause uneven deposit surfaces, but have different effects on runout distance, retained height, and scaling law constants. Particle sphericity, on the other hand, has trivial effects on granular collapse. These findings provide valuable insights into the exclusive effects of particle shapes on granular collapse response.
Article
Computer Science, Interdisciplinary Applications
M. Amine Benmebarek, Majid Movahedi Rad
Summary: The present study showcases the practical application of the 3D discrete-element method to visualize cemented grain crushing during pile penetration. By using a combination of the rigorous breakage criterion based on octahedral shear stress (OSS), the particle flow code PFC3D successfully simulates pile penetration and reproduces the concentration of crushed granular material particles near the pile tip and shaft. The proposed modeling approach is reliable and more accurate than existing methods.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Engineering, Chemical
Andrew M. Hobbs, Jin Y. Ooi, Manogna Adepu, Heather Emady
Summary: Conductive heat transfer in granular materials plays a crucial role in many industrial processes. A particle-based model, which incorporates the effect of interstitial gases, was validated through an experiment. The model demonstrates good agreement with experimental data, indicating its effectiveness in capturing the gas contribution in dynamic systems.
ADVANCED POWDER TECHNOLOGY
(2022)
Article
Engineering, Geological
Shaoheng Guan, Tongming Qu, Y. T. Feng, Gang Ma, Wei Zhou
Summary: In this article, a coupled finite element method and machine learning framework is proposed for simulating the mechanical responses of granular materials. Random loading paths and coupled simulations are used to generate training samples, and machine learning is employed to directly learn the constitutive relationship from the datasets. Active learning is used to evaluate the informativeness of data points and establish an effective resampling scheme.
Article
Engineering, Geological
Xiongying Ma, Hang Lei, Xin Kang
Summary: In this study, the effects of particle shape on the shear behavior of granular soils were investigated through experiments and simulations. It was found that increasing the shape parameter S-h can enhance the interlock between particles and limit the deformation in the direction of shearing. Additionally, changes in particle shape can significantly affect the fabric anisotropy of the soil.
INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS
(2022)
Article
Engineering, Geological
Ming Yang, Mahdi Taiebat, Patrick Mutabaruka, Farhang Radjai
Summary: Using the three-dimensional discrete element method, the study investigates the long-term evolution towards liquefaction state in granular materials composed of spherical particles under multidirectional cyclic shearing. It is found that liquefaction resistance is generally lower under multidirectional loading compared to unidirectional loading, and a shear strain-based liquefaction criterion is proposed. The analysis includes monitoring granular texture through various parameters and observing the relationship between deviatoric stress ratio and force and fabric anisotropies.