Article
Materials Science, Multidisciplinary
Na Deng, Antoine Wautier, Yannick Thiery, Zhen-Yu Yin, Pierre-Yves Hicher, Francois Nicot
Summary: This paper offers a fresh perspective on the classic concept of critical state in granular materials by suggesting that CS can be defined through a single proportional strain test. A comparison between proportional strain tests and biaxial tests shows that CS can act as an attractor, indicating that granular materials can preserve their properties while undergoing strain loading.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
Article
Mechanics
Nhu H. T. Nguyen
Summary: By coupling the volume of fluid and discrete element method, this study investigates impulse waves generated by partially and fully submerged granular collapse. It finds that the relative submerged depth and inter-particle friction are the main factors affecting the maximum wave amplitude, proposing an empirical model and demonstrating its practical application in estimating the maximum wave amplitude of partially submerged landslide events.
Article
Engineering, Chemical
J. N. M. Batista, D. A. Santos, R. Bettega
Summary: In this study, CFD-DEM was used to simulate the fluid dynamics inside a conical spouted bed operating with sorghum grains. By direct measurement, physical properties of the particulate phase and interaction parameters were determined and applied to the simulation, showing good agreement with experimental results.
Article
Engineering, Chemical
Chiho Hoshishima, Shuji Ohsaki, Hideya Nakamura, Satoru Watano
Summary: A calibration procedure for non-spherical cohesive particles using the DEM method is proposed in this paper, where the rolling friction coefficient and surface energy for cohesive force are calibrated based on the JKR theory. The validity of the calibrated parameters is confirmed through comparison with experimental data and mixing simulations in a V-shaped mixer, indicating their wide applicability.
Article
Engineering, Chemical
Sheng Zhang, Qingsong Zhao, Xueqian Ni
Summary: Sand reliquefaction has gained attention, but little is known about the influence of pre-shear strains on reliquefaction. Simulation tests were performed to investigate the macro behavior/microscopic fabrics of sand considering both residual strains and double amplitude of axial strain. Numerical results showed that double amplitude of axial strain had a significant effect on reliquefaction resistance, while the residual strains primarily influenced the evolution of porosity. A new judging criterion for anisotropic fabric during reconsolidation is proposed.
Article
Materials Science, Multidisciplinary
A. Rouzbeh, M. Sedighi, R. Hashemi
Summary: In this research, the effect of strain path on the microstructure, mechanical properties and forming limit diagram of roll-bonded Al/Mg two-layer sheet was experimentally investigated. The results showed that cross rolling produced a more uniform microstructure and no delamination occurred in the fabrication of bilayer sheets with two passes. Cross-rolled samples exhibited the best mechanical properties in terms of ultimate tensile strength and elongation. Additionally, cross rolling significantly reduced normal anisotropy. The forming limit diagram of cross-rolled samples exhibited an increase in FLD0 by 15.6%, 13.8%, and 5.7% compared to single-pass, two-pass direct rolling, and two-pass reverse rolling samples, respectively.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Engineering, Geological
Qirui Ma, Antoine Wautier, Wei Zhou
Summary: This study analyzes the microscopic mechanism of particle detachment in binary mixtures subjected to suffusion under different flow directions, finding that when the macro-flow direction is aligned with the principal direction of compression, the fluid flow intensifies, increasing erosion. Stress anisotropy influences detachment direction and results in directional variations in microstructural properties during suffusion under different flow directions.
Article
Engineering, Chemical
Aman Tripathi, Vimod Kumar, Arpit Agarwal, Anurag Tripathi, Saprativ Basu, Arijit Chakrabarty, Samik Nag
Summary: In this study, key simulation parameters were directly measured through laboratory experiments, and a new method was used to measure rolling friction of particles, leading to good agreement between experimental and simulation data in DEM simulations.
Article
Agronomy
Marcos A. Madrid, Jose M. Fuentes, Francisco Ayuga, Eutiquio Gallego
Summary: The determination of the angle of repose is essential for handling granular materials and designing equipment, while computational simulations are crucial to understand the micro-behavior of granular materials. The lack of a standard for experiments with granular materials of equivalent spherical radius larger than 2 mm poses a challenge. This study focuses on determining the rolling friction coefficient and finding an optimal procedure for the determination, as well as calibrating the coefficient using computational simulations.
Article
Computer Science, Interdisciplinary Applications
Hao Xiong, Yuanyi Qiu, Jiaying Liu, Zhen-Yu Yin, Xiangsheng Chen
Summary: This paper presents a numerical analysis of suffusion mechanisms in three representative volume elements under cyclic seepage. The effect of particle breakage on cyclic suffusion is assessed through varying breakage ratios. The study reveals that mass loss is intensified by particle breakage but is effectively inhibited under high-stress conditions. Fine particles exhibit different migration behaviors and the connectivity of the particle assembly weakens during cyclic seepage. Anisotropy in the normal contact force distribution increases as more particles are eroded.
COMPUTERS AND GEOTECHNICS
(2023)
Review
Engineering, Chemical
Rondinelli M. Lima, Rodolfo J. Brandao, Raphael L. Santos, Claudio R. Duarte, Marcos A. S. Barrozo
Summary: This study focused on experimental testing and validation of important DEM parameters for predicting the flow behavior of granular materials. The influence of material thickness on the measurement of coefficients of restitution was quantified, and statistical analysis using experimental design techniques identified significant input parameters in each measurement technique.
BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING
(2021)
Article
Biochemistry & Molecular Biology
Hao Wang, Xinyuanrui Wang, Yongping Wu, Song Wang, Junfei Wu, Ping Fu, Yang Li
Summary: The discrete element method coupled with computational fluid dynamics is used to study the micro-flow process of lignin particles in ceramic membranes. The shape of lignin particles is difficult to model accurately due to their various shapes in industry. To address this, a method was proposed to simplify the shape of lignin particles into spheres in a CFD-DEM simulation. The impact of the rolling friction coefficient on the deposition morphology of lignin particles was analyzed, and it was found that the rolling friction coefficient significantly affects the deposition morphology, coordination number, and porosity of the particles.
Article
Engineering, Multidisciplinary
Jichen Zhong, Jiao Wang, Xiangyu Li, Xihua Chu
Summary: Understanding the failure mechanisms of shale-like brittle materials is crucial for engineering safety. This research reconstructed a discrete element model that reflects the real rock properties and failure modes of shale specimens with different bedding angles. It revealed the relationship between micro-crack numbers and macroscopic stress, as well as analyzed the relative movement between deformed blocks. The model can predict the mechanical behavior of brittle rock and guide the application of shale-like brittle materials.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Metallurgy & Metallurgical Engineering
A. Rouzbeh, S. M. Atifeh, M. Sedighi, R. Hashemi
Summary: The effect of strain path change on the mechanical properties, formability, and forming limit of 1050 aluminum alloy is experimentally discussed in this study. The results show that cross rolling improves the mechanical properties and forming limit of the alloy significantly.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2023)
Article
Engineering, Chemical
Behrad Esgandari, Stefanie Rauchenzauner, Christoph Goniva, Paul Kieckhefen, Simon Schneiderbauer
Summary: In this study, a two-fluid model (TFM) and a computational fluid dynamics coupled to discrete element method (CFD-DEM) approach are employed to investigate the hydrodynamics of single and multiple-spout fluidized beds. The simulations are validated against experimental data and the results show good agreement between the TFM and CFD-DEM approaches in terms of volume fraction, solids velocities, solids fluxes, and granular temperature.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Geochemistry & Geophysics
Gang Ma, Jiangzhou Mei, Ke Gao, Jidong Zhao, Wei Zhou, Di Wang
Summary: Understanding the relationship between microslips and macroscopic stress fluctuations is crucial for gaining insights into geophysical processes such as earthquakes. This study uses discrete element method simulations and a machine learning approach to quantitatively connect microslips to stress fluctuations. The data-driven model successfully predicts the magnitude of stress fluctuation by incorporating the spatial distribution of microslips. The findings shed light on the mechanisms governing earthquake nucleation and the dynamics of earthquake cycles.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Yibo Zhang, Gang Ma, Longwen Tang, Wei Zhou
Summary: The study aims to establish a machine learning model that can identify the precursors of crystalline phases during the granular crystallization process. Through simulation experiments and the use of discrete element method, the study finds that the local volume fraction is an important structural signature in the generation of crystalline phases.
Article
Engineering, Geological
Wei Zhou, Shuhan Yang, Jiaying Liu, Gang Ma, Tianqi Qi, Mingchun Lin
Summary: Inter-particle friction is crucial for the mechanical behavior of granular materials, particularly under 3D non-axisymmetric loading conditions. The multiscale effects of inter-particle friction play a complex role in determining the behavior of granular materials. The evolution of strong contact network is found to be consistent with the overall stress tensor, regardless of the friction coefficient.
Article
Engineering, Geological
Yuxiong Zou, Gang Ma, Jiangzhou Mei, Jidong Zhao, Wei Zhou
Summary: The research explores the shape-dependent shear strength of granular materials and the influence of granular temperature on their properties. It is found that the nonlinearity of shear strength with particle shape and the coupling between rotational and translational particle dynamics are important factors affecting the macroscopic behavior of granular materials.
Article
Environmental Sciences
Chengqian Guo, Gang Ma, Haibin Xiao, Wei Zhou, Hongjie Chen, Zhiwei Zhou, Xiang Cheng
Summary: This article introduces the necessity and feasibility of using multi-source monitoring data in landslide displacement back analysis in reservoir areas. By utilizing surface InSAR and internal inclinometers, the article predicts landslide deformation through numerical modeling and evaluates the deformation state and stability of landslides, which is crucial for reservoir risk mitigation and the sustainable development of hydropower resources.
Article
Engineering, Geological
Gang Ma, Yihan Wang, Heng Zhou, Xi Lu, Wei Zhou
Summary: This study quantitatively investigates the morphology characteristics of fragments produced by crushing rock grains, showing that different-shaped grains yield different sizes of fragments, and there is no obvious relationship between the distribution of fragment shape descriptors and fragment size except for sphericity.
INTERNATIONAL JOURNAL OF GEOMECHANICS
(2022)
Article
Computer Science, Artificial Intelligence
Daren Zhang, Gang Ma, Zhuoran Deng, Qiao Wang, Guike Zhang, Wei Zhou
Summary: The aggregation of individuals facilitates information exchange and migration leads to dynamic community structure. Organisms' negative feedback regulation mechanism helps them in good living conditions. A novel particle swarm optimization algorithm with self-organizing topology and self-adaptive parameters (KGPSO) is proposed. K-Means clustering method divides the particle swarm into sub-swarms, and the optimal number of sub-swarms is determined. KGPSO maintains population diversity and uses adjusted parameters for dynamic balance between exploration and exploitation. Bayesian optimization tunes the hyperparameters of KGPSO. KGPSO performs best among tested PSO algorithms and shows excellent optimization capability in X-ray CT image enhancement.
APPLIED SOFT COMPUTING
(2022)
Article
Environmental Sciences
Jia Zhang, Gang Ma, Zhibing Yang, Qirui Ma, Wenyu Zhang, Wei Zhou
Summary: This study systematically investigated the influence of pore structure on the flow characteristics of landslide materials and found that tortuosity and global efficiency are related to permeability. Pore size heterogeneity and connectivity significantly affect the flow characteristics.
WATER RESOURCES RESEARCH
(2022)
Article
Engineering, Geological
Ni An, Gang Ma, Heng Zhou, Di Wang, Xi Lu, Wei Zhou
Summary: The study investigates the scale effect mechanism of sandy gravel material from Dashixia rockfill dam in China using the discrete element method (DEM). The results show that particle breakage weakens the shear strength of the material, while the widening of particle size distribution increases the resistance to deformation.
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
Jialin Cheng, Gang Ma, Guike Zhang, Qiao Wang, Wei Zhou
Summary: The deterioration of rockfill materials affects the safety and workability of rockfill dams. This study investigates the mechanical property deterioration of rockfill materials under different wetting-drying cycles and wetting duration. It is found that cyclic wetting-drying results in more significant particle breakage and microstructural changes compared to wetting alone.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Geosciences, Multidisciplinary
Renjun Zhang, Zhibing Yang, Russell Detwiler, Dongqi Li, Gang Ma, Ran Hu, Yi-Feng Chen
Summary: This study reveals that the effect of liquid cohesion on particle clogging has been overlooked in previous studies. Visualized experiments show that even a tiny amount of additional immiscible wetting liquid can dramatically enhance clogging. An experimental phase diagram of clogging patterns is obtained, and the combined effect of suspension composition and hydrodynamic condition on the clogging behavior is analyzed. A theoretical model of agglomerate size is proposed to quantify the capillary cohesion effect. This work improves the understanding of fines migration and particle-clogging behaviors in the subsurface and paves the way for controlling particle transport and clogging in various applications.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Computer Science, Interdisciplinary Applications
Jialin Cheng, Gang Ma, Guike Zhang, Xiaolin Chang, Wei Zhou
Summary: This study presents a theoretical model for analyzing the deterioration effect on the stress and deformation characteristics of rockfill materials during weathering. By introducing a deterioration coefficient, the stress and strain tensors before and after deterioration can be derived from granular matter mechanics and quantitatively evaluated using the Duncan-Chang EB model. The model predictions were verified through triaxial tests and showed good agreement with experimental results. The model can also predict the deteriorated stress and deformation characteristics after cyclic wetting-drying.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Materials Science, Multidisciplinary
Jiangzhou Mei, Gang Ma, Jiaying Liu, Francois Nicot, Wei Zhou
Summary: This paper investigates the transition between the solid and liquid phases of sheared granular materials from the perspective of the contact network. Persistent homology tools are used to quantify the dynamics of the contact network, and two important topological invariants, components and loops, are analyzed through numerical simulations. The study reveals the heterogeneous composition of the contact network and suggests a partition threshold for distinguishing strong and weak contact subnetworks. Mechanical precursors of the solid-liquid transition are identified during the shearing process. The study demonstrates the capability of the persistent homology method in bridging microscopic dynamics with macroscopic responses through the contact network.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Construction & Building Technology
Zhitao Ai, Gang Ma, Guike Zhang, Xiang Cheng, Quancheng Zou, Wei Zhou
Summary: The global construction of rockfill dams has reached a height of over 300 meters. However, monitoring techniques for high rockfill dams have not kept pace with dam design and construction. This study introduces the use of a shape accel array (SAA) for monitoring internal displacement in a 300-meter high earth core rockfill dam. Compared to conventional techniques, SAA is a data-intensive monitoring technique. The study also utilizes a parameter inversion method to predict rockfill dam deformation based on the intensive data obtained from SAA using a multiobjective optimization algorithm.
STRUCTURAL CONTROL & HEALTH MONITORING
(2023)