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arXiv 2023年

作者： Babaei, Hamed Pratoori, Raghunandan Levitas, Valery I. Department of Aerospace Engineering Iowa State University AmesIA50011 United States Departments of Mechanical Engineering Iowa State University AmesIA50011 United States Ames Laboratory Division of Materials Science and Engineering AmesIA50011 United States

Scale-free phase-field approach (PFA) at large strains and corresponding finite element method (FEM) simulations for multivariant martensitic phase transformation (PT) from cubic Si I to tetragonal Si II in a polycrystalline aggregate are presented. Important features of the model are large and very anisotropic transformation strain tensor ΕΕt = {0.1753;0.1753;−0.447} and stress-tensor dependent athermal dissipative threshold for PT, which produce essential challenges for computations. 3D polycrystals with 55 and 910 stochastically oriented grains are subjected to uniaxial strain- and stress-controlled loadings under periodic boundary conditions and zero averaged lateral strains. Coupled evolution of discrete martensitic microstructure, volume fractions of martensitic variants and Si II, stress and transformation strain tensors, and texture are presented and analyzed. Macroscopic variables effectively representing multivariant transformational behavior are introduced. Macroscopic stress-strain and transformational behavior for 55 and 910 grains are close (less than 10% difference). This allows the determination of macroscopic constitutive equations by treating aggregate with a small number of grains. Large transformation strains and grain boundaries lead to huge internal stresses of tens GPa, which affect microstructure evolution and macroscopic behavior. In contrast to a single crystal, the local mechanical instabilities due to PT and negative local tangent modulus are stabilized at the macroscale by arresting/slowing the growth of Si II regions by the grain boundaries and generating the internal back stresses. This leads to increasing stress during PT. The developed methodology can be used for studying similar PTs with large transformation strains and for further development by including plastic strain and strain-induced PTs. © 2023, CC BY.

关键词： Polycrystals

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SiO2-reinforced Poly (methyl methacrylate): Tribology Performance as Service Life Sensor

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Sensors and materials 2023年第8-2期35卷 2845-2854页

作者： Shi, Shih-Chen Zeng, Xin-Xing Chen, Tao-Hsing Wang, Chih-Chia Lin, Yue-Feng Department of Mechanical Engineering National Cheng Kung University No. 1 University Road Tainan City70101 Taiwan Department of Mechanical Engineering National Kaohsiung University of Science and Technology No. 415 Jiangong Rd. Sanmin Dist. Kaohsiung City807618 Taiwan Department of Chemical and Materials Engineering Chung Cheng Institute of Technology National Defense University No. 75 Shiyuan Road Taoyuan335009 Taiwan System Engineering and Technology Program National Yang Ming Chiao Tung University No. 1001 University Road Hsinchu300093 Taiwan Department of Mechanical Engineering National Chin-Yi University of Technology No. 57 Sec. 2 Zhongshan Rd. Taiping Dist. Taichung411030 Taiwan

Poly (methyl methacrylate) (PMMA), which is suitable for use in the human body owing to its biocompatibility, is commonly used in medical applications such as bone nails, bone cement, and dentures. However, owing to its hard and brittle nature, PMMA can cause damage when it is subjected to excessive stress and can also cause severe wear. In this study, three different sizes of silica particles were used as reinforcing additives to enhance the wear resistance of PMMA composites. A pin-on-disk wear test was conducted to record the coefficient of friction and wear volume, and the wear volume was measured using a 3D laser scanning microscope. In the wear test, the transfer film of micron and submicron particles produced a plowing effect, resulting in wide grooved wear scars and a higher wear rate than the raw material. The nanoparticle transfer film reduced direct material wear, the wear scars were fine and flat, and the wear rate was decreased, reducing the wear of SiO2-reinforced PMMA composites by 40%. The experimental results revealed that the wear volume is proportional to the wear time. In addition, the observed area of the transfer film on the wear counterpart can be used as a service life sensor of the coating material. © MYU K.K.

关键词： Tribology

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Anti-Termite Activity of Azadirachta excelsa Seed Kernel and Its Isolated Compound against Coptotermes curvignathus

Journal of the Korean Wood Science and Technology

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Journal of the Korean Wood science and Technology 2023年第3期51卷 157-172页

作者： Adfa, Morina Wiradimafan, Khafit Pratama, Ricky Febri Sanjaya, Angga Triawan, Deni Agus Yudha S., Salprima Ninomiya, Masayuki Rafi, Mohamad Koketsu, Mamoru Department of Chemistry Faculty of Mathematics and Natural Sciences University of Bengkulu Bengkulu38371 Indonesia Research Center of Sumatera Natural Product and Functional Materials University of Bengkulu Bengkulu38371 Indonesia Master of Chemistry Study Program Faculty of Mathematics and Natural Sciences University of Bengkulu Bengkulu38371 Indonesia Department of Chemistry and Biomolecular Science Faculty of Engineering Gifu University Gifu5011193 Japan Department of Chemistry Faculty of Mathematics and Natural Sciences IPB University Bogor16128 Indonesia Tropical Biopharmaca Research Center-Institute of Research and Community Services IPB University Bogor16128 Indonesia

Azadirachta excelsa, is a plant belonging to the same genus as Indian neem (Azadirachta indica), and its use as a pesticide is reported by few studies. Despite being a different species, it is expected to have the same biopesticide potential as A. indica. Therefore, this study aims to investigate the anti-termite activity of n-hexane and methanol extracts of A. excelsa seed kernel at various concentrations against Coptotermes curvignathus. The methanol extract demonstrated greater termicidal activity than n-hexane at doses test of 2%, 4%, and 8%. It also showed 100% termite mortality on the third day of administering the 8% dose. According to the gas chromatography with mass spectrometry data, the putative main components of the n-hexane extract were hexadecanoic acid, ethyl ester (18.99%), 9,12-octadecadienoic acid (Z,Z)-(16.31%), and 9-octadecenal (16.23%). In contrast, the principal constituents of methanol extract were patchouli alcohol (28.1%), delta-guaiene (15.15%), and alpha-guaiene (11.93%). Furthermore, limonoids profiling of A. excelsa methanol extract was determined using Ultrahigh-performance liquid chromatography coupled with quadrupole-Orbitrap high-resolution mass spectrometry. The number of limonoids identified tentatively was fifteen, such as 6-deacetylnimbin, nimbolidin C, nimbolide, 6-acetylnimbandiol, 6-deacetyl-nimbinene, salannol, 28-deoxonimbolide, gedunin, nimbandiol, epoxyazadiradione, azadirone, 2',3'-dihydrosalannin, marrangin, nimbocinol, and azadirachtin. They were the same as those reported in the seed and leaves of A. indica, but its largest component in A. excelsa was 6-deacetylnimbin. As a result, the presence of these compounds may be responsible for the anti-termite activity of A. excelsa seed kernel extract. Additionally, column chromatography of methanol extract yielded 6-deacetylnimbin, which was found to be antifeedant and termiticide against C. curvignathus. © 2023 The Korean Society of Wood science & Technology.

关键词： Mass spectrometry

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Metallic Slurry Preparation and Printability Assessment For Material Extrusion Additive Manufacturing

SSRN

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SSRN 2023年

作者： Li, Zhong Hu, Xiaogang Zhou, Yang Qu, Wenying Wen, Linju Meng, Xiaoxia Xu, Zhen Guo, Chuan Lu, Hongxing Zhu, Qiang Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China Shenzhen Key Laboratory for Additive Manufacturing of High-performance materials Southern University of Science and Technology Shenzhen518055 China Department of Mechanical Engineering Sciences University of Surrey Surrey GuildfordGU2 7XH United Kingdom BYD Auto Industry Company Limited Shenzhen518118 China Department of Mechanical Engineering Polytechnic University of Milan Milan20156 Italy

Material extrusion additive manufacturing of thermoplastics is so advanced due to the tunable rheological properties and hence a suitable printability, which is deficient for metals. Even though semi-solid modification and binder indirect modification are used to realize metal extrusion printing, the uncontrollable flow behavior and the metallurgical defects make it challenging to bridge this gap. In this study, mixed powder remelting and printability assessment were first proposed for producing metallic slurry with pre-designed microstructure and suitable printability. Specifically, the hypoeutectic Sn-Bi metallic slurry was obtained by remelting the mixed powder composed of SnBi58 powder and pure Sn powder. The microstructural characteristics at different temperatures were investigated, demonstrating the ability of microstructure predesign. Furthermore, the printability, including stability, extrudability, and buildability, was evaluated by an advanced rheometer and a screw-type 3D printer. The combined slurry preparation, printability assessment, and printing experiment provides a systematic method for parameters improvement to obtain the structural fidelity. © 2023, The Authors. All rights reserved.

关键词： Microstructure

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Nano-heterogeneity-stabilized and magnetic-interaction-modulated metallic glasses

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science China materials 2021年第7期64卷 1813-1819页

作者： Chengliang Zhao Anding Wang Aina He Chuntao Chang Chain-Tsuan Liu School of Mechanical Engineering Dongguan University of TechnologyDongguan 523808China Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China Department of Materials Science and Engineering College of Science and EngineeringCity University of Hong KongHong Kong 999077China

Because of their boundary-free and long-rangedisordered microstructure,Fe-based metallic glasses(MGs)exhibit an ultra-low pinning effect on the magnetic domain and unparalleled soft-magnetic properties[1-3],and thus a... 详细信息

关键词：非晶形成能力金属玻璃软磁性能非晶合金合金设计强化机制饱和磁感应强度磁相互作用

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Application of phase-field method in rechargeable batteries

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npj Computational materials 2020年第1期6卷 206-213页

作者： Qiao Wang Geng Zhang Yajie Li Zijian Hong Da Wang Siqi Shi Materials Genome Institute Shanghai UniversityShanghai 200444China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Physical Science and Engineering Division(PSE) King Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia Department of Mechanical Engineering Carnegie Mellon UniversityPittsburghPennsylvania 15213USA

Rechargeable batteries have a profound impact on our daily life so that it is urgent to capture the physical and chemical fundamentals affecting the operation and *** phase-field method is a powerful computational approach to describe and predict the evolution of mesoscale microstructures,which can help to understand the dynamic behavior of the material *** this review,we briefly introduce the theoretical framework of the phase-field model and its application in electrochemical systems,summarize the existing phase-field simulations in rechargeable batteries,and provide improvement,development,and problems to be considered of the future phase-field simulation in rechargeable batteries.

关键词： field phase method

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MFC 5.0: An exascale many-physics flow solver

arXiv

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arXiv 2025年

作者： Wilfong, Benjamin Le Berre, Henry A. Radhakrishnan, Anand Gupta, Ansh Vaca-Revelo, Diego Adam, Dimitrios Yu, Haocheng Lee, Hyeoksu Chreim, Jose Rodolfo Barbosa, Mirelys Carcana Zhang, Yanjun Cisneros-Garibay, Esteban Gnanaskandan, Aswin Rodriguez, Mauro Budiardja, Reuben D. Abbott, Stephen Colonius, Tim Bryngelson, Spencer H. School of Computational Science & Engineering Georgia Institute of Technology AtlantaGA30332 United States Mechanical and Materials Engineering Worcester Polytechnic Institute WorcesterMA01609 United States Daniel Guggenheim School of Aerospace Engineering Georgia Institute of Technology AtlantaGA30332 United States Department of Mechanical and Civil Engineering California Institute of Technology PasadenaCA91125 United States School of Engineering Brown University ProvidenceRI02912 United States Mechanical Science & Engineering University of Illinois at Urbana–Champaign UrbanaIL61820 United States Oak Ridge National Laboratory Oak RidgeTN37830 United States Hewlett Packard Enterprise BloomingtonMN55435 United States George W. Woodruff School of Mechanical Engineering Georgia Institute of Technology AtlantaGA30332 United States

Many problems of interest in engineering, medicine, and the fundamental sciences rely on high-fidelity flow simulation, making performant computational fluid dynamics solvers a mainstay of the open-source software community. A previous work (Bryngelson et al. Comp. Phys. Comm. (2021)) made MFC 3.0 a published, documented, and open-source source solver with numerous physical features, numerical methods, and scalable infrastructure. MFC 5.0 is a marked update to MFC 3.0, including a broad set of well-established and novel physical models and numerical methods and the introduction of GPU and APU (or superchip) acceleration. We exhibit state-of-the-art performance and ideal scaling on the first two exascale supercomputers, OLCF Frontier and LLNL El Capitan. Combined with MFC’s single-GPU/APU performance, MFC achieves exascale computation in practice. With these capabilities, MFC has evolved into a tool for conducting simulations that many engineering challenge problems hinge upon. New physical features include the immersed boundary method, N-fluid phase change, Euler–Euler and Euler–Lagrange sub-grid bubble models, fluid-structure interaction, hypo- and hyper-elastic materials, chemically reacting flow, two-material surface tension, and more. Numerical techniques now represent the current state-of-the-art, including general relaxation characteristic boundary conditions, WENO variants, Strang splitting for stiff sub-grid flow features, and low Mach number treatments. Weak scaling to tens of thousands of GPUs on OLCF Summit and Frontier and LLNL El Capitan see efficiencies within 5% of ideal to over 90% of their respective system sizes. Strong scaling results for a 16-times increase in device count see parallel efficiencies over 90% on OLCF Frontier. Other MFC improvements include ensuring code resilience and correctness with a continuous integration suite, the use of metaprogramming to reduce code length and maintain performance portability, and efficient computational r

关键词： Computational fluid dynamics

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Nonlocal Nernst-Planck-Poisson System for Modeling Electrochemical Corrosion in Biodegradable Magnesium Implants

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Journal of Peridynamics and Nonlocal Modeling 2025年第1期7卷 1-32页

作者： Hermann, Alexander Shojaei, Arman Höche, Daniel Jafarzadeh, Siavash Bobaru, Florin Cyron, Christian J. Institute of Material Systems Modeling Helmholtz-Zentrum Hereon Max-Planck-Str. 1 21502 Geesthacht Germany Institute of Surface Science Helmholtz-Zentrum Hereon Max-Planck-Str. 1 21502 Geesthacht Germany Department of Mathematics Lehigh University Bethlehem 18015 PA United States Department of Mechanical & amp Materials Engineering University of Nebraska-Lincoln Lincoln 68588-0526 NE United States Institute for Continuum and Material Mechanics Hamburg University of Technology Eissendorfer Strasse 42 Hamburg 21073 Germany

This paper provides a comprehensive derivation and application of the nonlocal Nernst-Planck-Poisson (NNPP) system for accurate modeling of electrochemical corrosion with a focus on the biodegradation of magnesium-based implant materials under physiological conditions. The NNPP system extends and generalizes the peridynamic bi-material corrosion model by considering the transport of multiple ionic species due to electromigration. As in the peridynamic corrosion model, the NNPP system naturally accounts for moving boundaries due to the electrochemical dissolution of solid metallic materials in a liquid electrolyte as part of the dissolution process. In addition, we use the concept of a diffusive corrosion layer, which serves as an interface for constitutive corrosion modeling and provides an accurate representation of the kinetics with respect to the corrosion system under consideration. Through the NNPP model, we propose a corrosion modeling approach that incorporates diffusion, electromigration and reaction conditions in a single nonlocal framework. The validity of the NNPP-based corrosion model is illustrated by numerical simulations, including a one-dimensional example of pencil electrode corrosion and a three-dimensional simulation of a Mg-10Gd alloy bone implant screw decomposing in simulated body fluid. The numerical simulations correctly reproduce the corrosion patterns in agreement with macroscopic experimental corrosion data. Using numerical models of corrosion based on the NNPP system, a nonlocal approach to corrosion analysis is proposed, which reduces the gap between experimental observations and computational predictions, particularly in the development of biodegradable implant materials. © The Author(s) 2024.

关键词： Biodegradation Corrosion modeling Electromigration Implant materials Nernst-Planck-Poisson system Peridynamics

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Metallic Slurry Preparation and Printability Assessment for Material Extrusion Additive Manufacturing

SSRN

引用

SSRN 2023年

作者： Li, Zhong Hu, Xiaogang Zhou, Yang Qu, Wenying Wen, Linju Meng, Xiaoxia Xu, Zhen Guo, Chuan Lu, Hongxing Zhu, Qiang Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China Shenzhen Key Laboratory for Additive Manufacturing of High-performance Materials Southern University of Science and Technology Shenzhen518055 China Department of Mechanical Engineering Sciences University of Surrey Guildford SurreyGU2 7XH United Kingdom BYD Auto Industry Company Limited Shenzhen518118 China Department of Mechanical Engineering Polytechnic University of Milan Milan20156 Italy

关键词： Microstructure

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Design and Modeling of a Cable-Driven Hollow Continuum Manipulator

Design and Modeling of a Cable-Driven Hollow Continuum Manip...

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International Conference on Advanced Robotics and Mechatronics (ICARM)

作者： Changchao Sun Rongjie Kang Peikang Yuan Le Chang Xin Dong Shumin Wan Zhibin Song Jian S. Dai Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education School of Mechanical Engineering Tianjin University Tianjin China Department of Mechanical Materials and Manufacturing Engineering University of Nottingham Nottingham U.K. Institute for Robotics Southern University of Science and Technology Shenzhen China

Continuum manipulators (CMs) have redundancy and flexibility and show good adaptability in unstructured environments. Traditional CMs mostly utilize a backbone to provide structural support and produce bending, which limits the internal space. In this paper, an internally hollow CM is designed. The orthogonal segment ensures two bending degrees of freedom in a single module. In this design, each module contains four cables that can be divided into two pairs driven by two motors respectively, forming a closed-loop cable drive mechanism. For each pair of cables, they have different length change when the module bends. Thus, the actuation space of the manipulator is further mapped to the “motor space” to form the complete kinematic model. As the multi-moduled body has motion coupling, kinematic decoupling is achieved through using Bowden tube. Simulated and experimental results show that the CM designed in our work has high structural load capacity and flexible motion ability.

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