Article
Chemistry, Multidisciplinary
Jiangu Qian, Chuang Zhou, Weiyi Li, Xiaoqiang Gu, Yongjun Qin, Liangfu Xie
Summary: This study uses the discrete element method to simulate shear tests and reveals the key factors influencing K-0 of granular materials. The results show that particle shape, initial void ratio, and inter-particle friction angle significantly affect K-0 values. Based on the experimental results, a more accurate empirical equation is proposed that considers the effect of particle shape.
APPLIED SCIENCES-BASEL
(2022)
Article
Mathematics, Interdisciplinary Applications
Tao Zhang, Sui Wang, Shuyang Yu, Zhaohua Sun, Chuanfeng Fang, Shuren Wang
Summary: This paper investigates the effects of particle size distribution (PSD) and rolling resistance (RR) on the coefficient of lateral earth pressure at rest (K-0) through numerical one-dimensional compression tests on granular soils. The results show that both PSD and RR impact K-0 and its compression characteristics. PSD has a stronger influence on the local ordering structure and contact force network than RR. Higher coefficient of uniformity (C-u) or rolling resistance coefficient (mu(r)) leads to a decrease in the mean coordination number, resulting in lower K-0 measurements.
COMPUTATIONAL PARTICLE MECHANICS
(2023)
Article
Engineering, Chemical
Jinpeng Qiao, Kejun Dong, Chenlong Duan
Summary: The study utilized the discrete element method to investigate the segregation process of a single large intruder in a vibrated bed of small particles, focusing on the effects of vibration conditions and intruder shape on the intruder's dimensionless ascending velocity. It was found that the ascending velocity changes with the variation of vibration amplitude and frequency, and is influenced by the shape of the intruder.
Article
Engineering, Chemical
Yanjie Li, Qi Zhang, Xia Hua, Yu Guo, Jennifer S. Curtis
Summary: This study simulates the triaxial compressions of spherical granular beds reinforced by immersed flexible fibers using the discrete element method (DEM). The results show that the yield stresses of the particle beds increase with higher fiber concentration or aspect ratio, but are not affected by fiber flexibility. The configuration of the immersed fibers significantly impacts the compressive strength of the beds.
Article
Computer Science, Interdisciplinary Applications
Siqiang Wang, Qi Zhang, Shunying Ji
Summary: A CUDA-GPU parallel algorithm based on super-quadric elements is developed to simulate large-scale non-spherical granular systems, demonstrating its applicability and reliability through various tests.
ADVANCES IN ENGINEERING SOFTWARE
(2021)
Article
Engineering, Multidisciplinary
Qizhi Chen, Chuli Xu, Baoping Zou, Zhanyou Luo, Changjie Xu, Xu Long
Summary: The soil arching effect, which refers to the load transformation from the yielding part to the adjacent part of the soil, is important in the design of geotechnical infrastructures. This paper presents the research on the earth pressure of the trapdoor problem using the three-dimensional discrete element method. Different aspects such as the variation of earth pressure, the distribution of vertical and lateral earth pressure, and the contact force chain are studied based on five 3D trapdoor models. The research results show the decrease and subsequent increase of earth pressure on the trapdoor after its downward movement, as well as the different distributions in the loose and stable areas.
CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES
(2023)
Article
Engineering, Chemical
Ali Abbas Zaidi
Summary: This article studies the resistance or granular drag force experienced by an intruder during penetration into granular material, and explains the underlying physics. Numerical simulations using the discrete element method (DEM) show that particles undergo a jamming transition below the intruder, and the region of jammed particles increases with the depth of intrusion, which leads to an increase in the granular drag force.
Article
Engineering, Mechanical
Hong-wu Song, Wenlong Xie, Shi-Hong Zhang, Weihao Jiang, Lucian Lazarescu, Dorel Banabic
Summary: This study presents a new push bending method using granular media filler for manufacturing thin-walled tubes with small relative bending radius. By investigating the pressure distribution of the granular system, the method strengthens the bending deformation of the tubes, effectively preventing the formation of defects such as wrinkles.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2021)
Article
Computer Science, Interdisciplinary Applications
Shiwei Zhao, Jidong Zhao
Summary: SudoDEM is a novel open-source discrete element code for efficient modeling of non-spherical particles in 2D and 3D, featuring a rich library of particle shapes and efficient contact detection algorithms. The code has been validated and demonstrated its robustness, efficiency and versatility in providing realistic solutions to granular mechanics problems.
COMPUTER PHYSICS COMMUNICATIONS
(2021)
Article
Engineering, Geological
Yuxuan Wen, Yida Zhang
Summary: This study uses the discrete element method to conduct a series of tests and finds a tight correlation between the void ratio and the fabric tensor of granular soils. By plotting the void ratio data against the first two invariants of the fabric tensor, a unique surface is obtained. The robustness of this relation is confirmed through testing samples with different initial void ratios under complex loading paths.
Article
Engineering, Geological
Xiaoqiang Gu, Xiaomin Liang, Jing Hu
Summary: Fabric anisotropy is a sought-after micro index to correlate macro mechanical responses of granular materials. In this work, discrete element method (DEM) is utilized to simulate multi-directional bender element tests in granular soils to obtain the evolution of wave velocities during drained conventional triaxial (CT) and true triaxial (TT) tests, and the contact normal based fabric is simultaneously monitored for bridging the fabric anisotropy and wave velocity anisotropy. The results show that stress-normalized wave velocities and microscopic fabric, including contact normal distribution and coordination number, remain nearly constant until a stress ratio threshold is reached. After the threshold value is reached, stress-normalized wave velocities start to decrease, especially in the minor principal stress direction, accompanied by significant adjustment of coordination number and fabric anisotropy. The results also reveal that the normalized wave velocity depends on the contact normal densities in the wave propagation and particle oscillation directions. With the contact normal distribution represented by a density function, a good linear relationship between the microscopic fabric anisotropy and macroscopic wave velocity anisotropy is obtained for both CT and TT tests.
Article
Engineering, Chemical
Ting Qiao, Lu Liu, Shunying Ji
Summary: This study develops a coupling method based on superquadric elements to describe the interaction between non-spherical solid particles and fluids. The discrete element method (DEM) and smoothed particle hydrodynamics (SPH) are used to simulate granular materials and fluids, respectively. The coupling force is calculated using a repulsive force model, and a contact detection method is established to capture the shape of the superquadric element and calculate the distance between the fluid particle and the surface of the superquadric element. Simulation cases verify the validity of the proposed coupling method, which accurately represents the water entry process of spherical solid particles and can simulate fluid-particle systems with solid particles of multiple shapes.
Article
Engineering, Chemical
Zhuo Cui, Dou Huang, Chao Dang, Li Jia
Summary: The pressure drop in wicks significantly impacts the heat transfer rates of heat pipes. This study found that wicks made of spherical particles had lower pressure drops, while the pressure drop in wicks made of irregular particles decreased with increasing porosity. Different correlations were used to predict pressure drops in wicks, with the Morcom correlation providing accurate predictions for spherical particle wicks and the Meyer and Smith correlations being better for irregular particle wicks.
Article
Computer Science, Interdisciplinary Applications
Ming Xu, Jinwu Guo
Summary: The research using the discrete element method to simulate the development of lateral earth pressure of granular materials under cyclic loading found that lateral stresses increase continuously for both loose and dense samples during cycling. The unique relationship between deviator stress ratio on the macro-scale and deviator fabric of strong contacts on the micro-scale was revealed through micro response investigation. The influence of particle shape on macro and micro responses was highlighted through lateral cyclic loading tests on samples with spherical particles.
COMPUTERS AND GEOTECHNICS
(2021)
Article
Engineering, Chemical
Xiangui Chen, Yixue Peng, Chengbo Li, Chuang Zhao
Summary: Discrete element method is used to simulate sound propagation in particle systems and calculate sound velocities. The stiffness of the system explains the variation of sound velocity with stress conditions. The simulation results are consistent with theoretical predictions and the influence of particle shape on sound velocity is determined.
Article
Engineering, Multidisciplinary
Shiwei Zhao, Zhengshou Lai, Jidong Zhao
Summary: This article presents a novel approach to accelerate particle-based simulations by leveraging ray tracing cores in addition to CUDA cores on RTX GPUs. A new, general-purpose RT-based neighbor search algorithm is proposed and benchmarked with a prevailing cell-based one. The study demonstrates that the RT-based simulations are 10%-60% faster than the cell-based ones.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Hao Chen, Shiwei Zhao, Jidong Zhao, Xiaowen Zhou
Summary: This study proposes a generalized contact scheme based on a hybrid scheme of material point method (MPM) and discrete element method (DEM) to model multi-body and multi-material interactions. The scheme contains two novel features of particle-particle and particle-structure contact schemes guided by a DEM contact model. It demonstrates that the generalized contact scheme can flexibly capture the mechanical responses of multi-body and multi-material systems in MPM.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Weijian Liang, Jidong Zhao, Huanran Wu, Kenichi Soga
Summary: We propose a multiscale, multiphysics approach that combines two-phase material point method (MPM) with discrete element method (DEM) (MPM-DEM) to simulate the hydro-mechanical coupling responses of saturated granular media under different loading conditions. The proposed approach is validated and then used to simulate various engineering problems, demonstrating its power and versatility in capturing the complicated interactions exhibited in saturated granular media. Furthermore, connections between macroscopic observations and microstructural mechanisms are established to provide multiscale insights into the dynamic responses of saturated sand.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Geological
Shuai Huang, Linchong Huang, Zhengshou Lai, Jidong Zhao
Summary: This study presents a numerical modeling of coral sand using the discrete element method, taking into account the irregular shape and intraparticle voids. The developed model is calibrated and validated against laboratory tests, showing good accuracy and validity. The performance of two different particle models, spherical harmonics and level set, is also compared, providing a useful reference for practical applications.
ENGINEERING GEOLOGY
(2023)
Article
Engineering, Geological
Yong Kong, Xingyue Li, Jidong Zhao, Mingfu Guan
Summary: This study uses a physics-based coupled computational fluid dynamics and discrete-element method (CFD-DEM) to simulate a flexible ring-net barrier and model a debris flow. The numerical predictions show reasonable consistency with large-scale experiments. Systematic simulations are performed to examine the load-deflection mechanisms and quantify the load-deflection modes. The study improves understanding for practical design of flexible barriers in mitigating debris flows.
Article
Engineering, Mechanical
Tongming Qu, Shaoheng Guan, Y. T. Feng, Gang Ma, Wei Zhou, Jidong Zhao
Summary: This study aims to develop a deep active learning strategy to improve the data-driven constitutive modelling of granular materials. The results confirm the importance of active learning in this field and suggest its potential application in other data-centric applications in various science and engineering fields.
INTERNATIONAL JOURNAL OF PLASTICITY
(2023)
Article
Engineering, Multidisciplinary
Zhengshou Lai, Jidong Zhao, Shiwei Zhao, Linchong Huang
Summary: This paper presents an improved framework of the immersed boundary method (IBM)-based fully resolved computational fluid dynamics (CFD) and discrete element method (DEM), emphasizing on irregular-shaped particles and their implications to particle-fluid interactions. The proposed SDF-CFD-DEM framework leverages signed distance field (SDF) as a generic interface for universal modeling of arbitrarily shaped particles interacting with multiphase fluids. It is validated and demonstrated with examples including particle settling, drafting-kissing-tumbling, immersed granular collapse, and mudflow, showing good accuracy, robustness, and potential for efficient computational modeling of granular flows with arbitrary-shaped particles.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Shiwei Zhao, Jidong Zhao
Summary: This paper presents a novel approach, called Ray Tracing Discrete Element Method (RTDEM), for efficiently simulating particles with arbitrary shapes. The method uses a triangular mesh and template meshes, along with ray tracing-based algorithms and discrete potential field functions, to accurately and efficiently detect and resolve contacts between the particles.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Mechanics
Y. T. Li, N. Guo, Z. X. Yang, J. D. Zhao
Summary: This paper presents a numerical study on the behavior of suspensions of non-Brownian grains in a Couette flow. The results show that both the inertia and the grain shape affect the interactions between grains and the fluid, contributing to the overall shear stress and rheology of the suspension. The study also reveals the presence of grain layering near the boundary walls, which becomes more pronounced with higher solid concentration and inertia, and increased non-circularity in grain shape. The correlation between suspension viscosity and grain microstructure and kinematics is also investigated.
Review
Physics, Applied
Jidong Zhao, Shiwei Zhao, Stefan Luding
Summary: This Technical Review provides an overview of computational modeling of granular matter, focusing on the role of particle shape and future challenges.
NATURE REVIEWS PHYSICS
(2023)
Article
Engineering, Multidisciplinary
Changyi Yang, Fan Zhu, Jidong Zhao
Summary: This paper presents a novel computational approach for modelling fluid-driven fracturing in quasi-brittle solids using peridynamics. The approach combines total-Lagrangian formulation and semi-Lagrangian formulation to solve the Navier-Stokes equation and quantify the forces at the fluid-solid interface using a non-local differential operator. The proposed approach offers a unified peridynamics-based framework that enables simulations of a wide range of fluid-driven fracturing problems in solids and has been validated through various classic problems.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2024)
Article
Engineering, Geological
Ke Shi, Fan Zhu, Jidong Zhao
Summary: This study uses a multiscale computational approach to simulate the shearing behavior of crushable granular sand at critical state and analyzes its characteristics. The results show that the critical state has unique features for crushable granular sand, including critical state stress ratio, void ratio, breakage index, and shape descriptors.
Article
Engineering, Multidisciplinary
Jidu Yu, Jidong Zhao, Weijian Liang, Shiwei Zhao
Summary: In this study, a stabilized material point method (MPM) is developed for modeling the thermo-hydro-mechanical (THM) response of porous media undergoing large deformations. A novel staggered solution scheme is proposed, and the validity and efficiency of the method are demonstrated through benchmark problems.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2024)
