Article
Computer Science, Interdisciplinary Applications
Shirui Zhang, Wenfang Xiao, Weiwei Jia
Summary: Understanding the failure process of brittle rocks at both macroscopic and microscopic levels is important for predicting their strength and deformation characteristics. However, studying the evolution of microcracks in these rocks is challenging due to their heterogeneity. In this study, a multiscale grain-based model was developed based on FDEM to simulate the behavior of brittle rocks at the grain scale. The model considered the actual grain size, inter-grain and intra-grain contacts, as well as local polycrystal inclusions and internal cleavage. Simulated tests, including uniaxial tensile and compression tests, were conducted based on laboratory data. The results showed that the transgranular fracture capacity played a crucial role in mesoscopic fracture simulation, and the difference in inter-grain and intra-grain tensile strength controlled the failure mechanism of rock samples under uniaxial compression. The ability of minerals to absorb elastic strain energy significantly influenced the path of microcracks and the transition from tension to shear failure mechanisms. The findings of this study provide insights into the microcrack evolution mechanism in heterogeneous rocks and a method for comprehensive analysis of crack propagation and energy evolution.
SIMULATION MODELLING PRACTICE AND THEORY
(2023)
Article
Engineering, Environmental
M. Hadian, K. A. Buist, A. N. R. Bos, J. A. M. Kuipers
Summary: ThermoCatalytic Decomposition of methane (TCD) is studied for converting natural gas into hydrogen and functional carbon. A particle growth model is developed to understand the limitations and optimal parameters of this process. Temperature plays a significant role in regulating kinetic rate, growth rate, and catalyst deactivation, crucial for the production of nano-carbon.
CHEMICAL ENGINEERING JOURNAL
(2021)
Article
Materials Science, Multidisciplinary
C. Degueldre, R. J. Wilbraham, J. Fahy, S. M. Green
Summary: The study investigates the secondary recrystallisation and abnormal grain growth behavior in a specific stainless steel alloy pinned by nano-particles under certain stress and annealing conditions. Tests were conducted to examine the effect of grain size distributions and growth models with changes in time and temperature. It is suggested that a more precise analysis of grain and nano-particle sizes is essential for an accurate evaluation of incubation time, along with further research and development work to apply the model and prevent secondary grain growth.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Engineering, Chemical
Zuyang Zhang, Daoyin Liu
Summary: This study develops a cohesive crack model based on the discrete-finite element method (FDEM) to simulate the collision behavior between a complex agglomerate and a wall. The model is validated by comparing the simulation results with experimental data. The sensitivity analysis reveals that the fragmentation distribution and damage ratio have specific relationships with other parameters.
Review
Engineering, Civil
Fateme Najafkhani, Sara Kheiri, Bita Pourbahari, Hamed Mirzadeh
Summary: This overview article presents recent progress in the kinetics of grain coarsening and abnormal grain growth (AGG), summarizing factors affecting grain growth kinetics and critical values for various engineering alloys, as well as discussing the mechanisms and kinetics of AGG.
ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING
(2021)
Article
Materials Science, Multidisciplinary
Victor Caso Moreira, Andre Paulo Tschiptschin, Julio Cesar Dutra
Summary: A new methodology based on network analysis is proposed for characterizing microstructural heterogeneities in metals and alloys. This method overcomes the limitations of traditional network centralities by taking into account topological constraints during normal grain growth. It has been successfully tested for the characterization of abnormal grain growth and a pre-self-similar state during normal grain growth.
MATERIALS CHARACTERIZATION
(2023)
Article
Computer Science, Interdisciplinary Applications
Javad Yahaghi, Hongyuan Liu, Andrew Chan, Daisuke Fukuda
Summary: This paper presents a new three-dimensional grain-based hybrid finite-discrete element method parallelized using general-purpose graphic processing units (GPGPUs), which is applied to study the failure process of sedimentary fine-grained sandstones. The grain-based method considers the actual microstructures of rocks and uses Voronoi or grain-growth tessellations to model their failures. In addition to GPGPU parallelization, a novel semi-adaptive contact activation approach and an efficient tetrahedron-to-point contact interaction algorithm are implemented to accelerate the grain-based modeling.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Nanoscience & Nanotechnology
Yue Li, Zhijun Wang, Junjie Li, Jincheng Wang
Summary: The study introduces a novel approach to describe grain growth kinetics, which effectively reflects the impact of grain-environment heterogeneity on the normalized grain growth rate.
SCRIPTA MATERIALIA
(2022)
Article
Engineering, Geological
Fateme Naseri, Naser Hafezi Moghadas, Morteza Beiki, Hodayseh Khakzad Suchelmaei, Mina Koohdarzi Moghadam, Mahnaz Sabbagh Bejestani
Summary: By testing rock samples from carbonate oil fields and using methods such as fuzzy clustering, adaptive neuro-fuzzy inference system, and particle swarm optimization algorithm, the shear strength parameters of the Mohr-Coulomb failure criterion were estimated, providing a convenient method for predicting the risk of borehole collapse.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Chemistry, Inorganic & Nuclear
Yunjing Shi, Xiaoyu Dong, Bo Shen, Jiwei Zhai
Summary: In this study, the piezoelectric properties of 0.7BFBT-T were enhanced through quenching. A suitable quenching temperature increased the content of the rhombohedral phase, leading to a highly distorted structure and magnification of the dipole moment, which was beneficial for enhancement of the polarity. Furthermore, quenching inhibited oxygen vacancies and increased the size and orderliness of domains, reducing the pinning effect.
INORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Materials Science, Multidisciplinary
Partha Sarathi De, Subramanya Sarma Vadlamani, Srikanth Vedantam
Summary: Anomalous grain growth in metals and ceramics occurs when a few grains grow abnormally fast compared to the surrounding matrix grains. This phenomenon, often associated with first order phase transitions in grain boundaries, is not well understood. In this study, a thermodynamically consistent mechanism for abnormal grain growth is proposed, involving the presence of complexion transitioned boundaries at triple junctions. Simulations based on a phase field model show that abnormal grain growth can occur without mobility advantage or additional driving forces, capturing microstructural features observed experimentally. The fraction of complexion boundaries plays a significant role in controlling the extent of abnormal grain growth.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Physics, Fluids & Plasmas
Tatu Pinomaa, Nana Ofori-Opoku, Anssi Laukkanen, Nikolas Provatas
Summary: The vector order parameter phase field model is proposed for modeling polycrystalline solidification of alloys, showing quantitative behavior in binary alloys and consistent results with earlier theoretical work on grain boundary energy and solute back-diffusion. This model serves as a practical computational tool for simulating polycrystalline materials and can be extended to model multiple solid phases in higher dimensions.
Article
Computer Science, Interdisciplinary Applications
Yuan Chen, Gang Ma, Wei Zhou, Deheng Wei, Qi Zhao, Yuxiong Zou, Giovanni Grasselli
Summary: By combining X-ray micro-CT and hybrid finite-discrete element method, this study investigates the mechanical behaviors of granular materials. The research reveals that granular materials deform plastically through spatially localized zones, which control the macroscopic responses of the system. The proposed tool provides insights into bridging length scales from particle to granular system.
COMPUTERS AND GEOTECHNICS
(2021)
Article
Materials Science, Multidisciplinary
Thomas Grippi, Stephanie Behar-Lafenetre, Holger Friedrich, Daniel Haas, Uwe Schenderlein, Sylvain Marinel, Charles Maniere
Summary: The complexity of liquid phase sintering of silicon nitride requires the use of advanced gas pressure sintering (GPS) industrial process. Sintering additives are developed to achieve high mechanical properties of this challenging material. The microstructure development during the thermal treatment at temperature close to 1800 degrees C significantly affects the properties and GPS process of silicon nitride, particularly the grain growth. In this study, an experimental design is used to investigate the microstructural development during the final stage of sintering. The grain size and porosity data are analyzed to identify the experimental grain growth under different holding times and temperatures, considering the impact of heating kinetics regime and gas pressure furnace environment.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Dejian Sun, Ke Zhao, Guizhong Li, Jiachen Kang, Ka Gao, Zan Zhang, Yang Gao, Lei Fan, Linan An
Summary: The nickel-based superalloy prepared by hot oscillating pressing (HOP) showed higher yield strength and ultimate tensile strength compared to the hot pressing (HP) processed sample, with significantly improved elongation. The enhanced elongation in the HOPed sample is likely attributed to the application of oscillatory pressure, which promoted inter-particle boundary sliding and/or plastic deformation during densification process.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
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)
