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Combined anisotropic and cyclic constitutive model for laser powder bed fusion fabricated aluminum alloy

Chinese Journal of Aeronautics 2025年第1期38卷 165-184页

作者： Fei-Fan LI Jihong ZHU Weihong ZHANG Shifeng WEN Jingwen SONG Jun MA Gang FANG State IJR Center of Aerospace Design and Additive Manufacturing School of Mechanical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China School of Materials Science and Engineering Northwestern Polytechnical UniversityXi'an 710072China Department of Mechanical and Industrial Engineering Norwegian University of Science and TechnologyTrondheim 7491Norway State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

This study presents new methods to effectively model the anisotropic yielding and hardening behavior of laser powder bed fusion fabricated aluminum alloy under both monotonic and cyclic loading *** proposed model combines the yield surface-interpolation method to accurately describe the anisotropic hardening rates in various directions,with the Chaboche kinematic hardening rule to precisely reflect the cyclic *** numerical implementation of the combined anisotropic and cyclic constitutive model,a fully implicit stress integration algorithm based on return mapping method is ***,the multiple parameters associated with the model are categorized and identified in an uncoupled *** isotropic and cyclic hardening parameters are determined by an inverse method,and the stability of the optimization outcomes is validated by applying different starting points for the ***,the back-stress effect on the identification of anisotropic parameters associated with the stress invariant-based Hill48 yield function is considered for the first *** consideration leads to an improved prediction accuracy compared to the identification of anisotropic parameters without considering back-stress *** combined anisotropic and cyclic constitutive model,along with the calibrated parameters,are proven capable of accurately reproducing the intricate deformation behavior of laser powder bed fusion fabricated AlSi10Mg.

关键词： Constitutive models Anisotropy Kinematic hardening Laser powder bed fusion Aluminum alloys

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Experimental investigation on diesel-hydrogen in dual-fuel mode application and its comparison with compressed natural gas

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International Journal of Hydrogen Energy 2025年 134卷 212-228页

作者： Shamkuwar, Sonal Atmanli, Alpaslan Bandyopadhyay, Debjyoti Sale, Onkar Deore, Aditya Kharde, Shubham Department of Mechanical Engineering Vishwakarma Institute of Technology Pune India Department of Mechanical Engineering National Defence University Ankara06654 Turkey Engine Development Laboratory The Automotive Research Association of India Pune India Vishwakarma Institute of Information Technology Pune India

This study investigates the effect of introducing Hydrogen (H2) and Compressed Natural Gas (CNG) in a single-cylinder diesel engine operating at constant 1500 RPM under varied engine load conditions (25 %, 50 %, 75 %, and 100 %). Diesel used as a pilot fuel and gaseous fuels injected in manifold at a rate of 7 μs (μs) and 10 μs. In terms of pressure rise and rate of heat release, the Diesel Dual Fuel (DDF) engine performs poorly at low load and approximates diesel engine at high load. Addition of hydrogen in a DDF engine results in a significant improvement in Brake Thermal Efficiency (BTE), a considerable decrease in engine's Brake Specific Energy Consumption (BSEC) and carbon emissions. At a full load and injection rate of 10 μs, Oxides of Nitrogen (NOx) emission was 1383 ppm and 973 ppm for hydrogen and CNG respectively as compared to 1407 ppm for diesel engine. The higher energy share of CNG results is same thermal efficiency as that of H2, at moderate and higher loads. The study shows that H2 outperformed CNG in terms of combustion, performance and emissions (NOx is the exception). H2 injection strategies with dedicated injector should be adapted in DDF to make it potential alternative. © 2025 Hydrogen Energy Publications LLC

关键词： Compressed natural gas

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Enhanced engineering and biocidal polypropylene filaments enabling melt reduction of AgNO_(3) through PVP agent:A scalable process for the defense industry with MEX additive manufacturing

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Defence Technology(防务技术) 2025年第2期44卷 52-66页

作者： Markos Petousis Nikolaos Michailidis Vassilis Papadakis Apostolos Argyros Mariza Spiridaki Nikolaos Mountakis John Valsamos Nektarios K.Nasikas Amalia Moutsopoulou Nectarios Vidakis Department of Mechanical Engineering Hellenic Mediterranean UniversityHeraklion 71410Greece Physical Metallurgy Laboratory Mechanical Engineering DepartmentSchool of EngineeringAristotle University of ThessalonikiThessaloniki 54124Greece Centre for Research&Development of Advanced Materials(CERDAM) Centre for Interdisciplinary Research and InnovationBalkan CentreBuilding B’10th Km Thessaloniki-Thermi RoadThessaloniki 57001Greece Institute of Electronic Structure and Laser of the Foundation for Research and Technology-Hellas(IESL-FORTH)e Hellas N.Plastira 100mHeraklion 70013Greece Department of Industrial Design and Production Engineering University of West AtticaAthens 12243Greece Division of Mathematics and Engineering Sciences Department of Military SciencesHellenic Army AcademyGR 16673VariAtticaGreece

This study focused on the production of polypropylene(PP)/silver(Ag)composites via additive *** study aimed to enhance the quality of medical-grade PP in material extrusion(MEX)three-dimensional printing(3DP)by improving its mechanical properties while simultaneously adding antibacterial *** latter can find extremely important and versatile properties that are applicable in defense and security ***/Ag nanocomposites were prepared using a novel method based on a reaction occurring while mixing appropriate quantities of the starting polymers and additives,namely polyvinylpyrrolidone(PVP)as the matrix material and silver nitrate(AgNO_(3))as the *** process produced three-dimensional(3D)printed filaments,which were then used to create specimens for a series of standardized *** was found that the mechanical properties of the nanocomposites were enhanced in relation to pristine PP,especially for the PP matrix with various loadings of AgNO_(3)and PVP,such as 5.0 wt%and 2.5 wt%,*** voids,inclusions,and actual-to-nominal dimensions also showed improved *** 3DP specimens exhibited a more effective biocidal performance against Staphylococcus aureus than Escherichia coli,which developed an inhibition zone only in the case of PP with filler loading percentages of AgNO_(3)and PVP at 10.0 wt%and 5.0 wt%,respectively Compounds possessing such properties can be beneficial for various applications requiring increased mechanical properties and biocidal capabilities,such as in the Defence or medical industries.

关键词： Polypropylene(PP) Polyvinyl pyrrolidone(PVP) Silver nitride(AgNO_(3)) In-situ reactive melt mixing process Material extrusion(MEX)3D printing Biocidal performance

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Optical and mechanical properties of Gd2O3-MgO nanocomposites sintered by hot-isostatic-pressing using the nanopowders via glycine combustion method 10

Optical and mechanical properties of Gd2O3-MgO nanocomposite...

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2024 10th International Forum on Manufacturing Technology and engineering Materials, ICMTEM 2024

作者： Tang, Hengwei Wu, Nan Hu, Kai Shao, Cen Hou, Zhaoxia Liaoning Province Key Laboratory of Micro-Nano Materials Research and Development School of Mechanical Engineering Shenyang University Shenyang110044 China Jiangsu Xiyi Advanced Materials Research Institute of Industrial Technology Xinyin 221499 China

The glycine combustion method combined with hot-isostatic-pressing sintering technology is an effective approach to fabricating nanocomposites. We reported that the Gd2O3-MgO nanocomposites had excellent optical and mechanical performances. The nanopowders with low agglomeration were obtained by elaborating the mole ratio of metal cation to glycine. The excellent optical transmittance (78.2%∼80.8%) over 3-6 μm and the high values for Vickers hardness (9.6±0.3 GPa) and bending strength (192.7±8.1 MPa) were obtained by hot-isostatic-pressing sintering at 1350°C with 200 MPa pressure. © Published under licence by IOP Publishing Ltd.

关键词： Vickers hardness

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Enhanced 3D printing and crack control in melt-grown eutectic ceramic composites with high-entropy alloy doping

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材料科学技术（英文版） 2025年第6期209卷 64-78页

作者： Zhonglin Shen Haijun Su Minghui Yu Yinuo Guo Yuan Liu Hao Jiang Xiang Li Dong Dong Peixin Yang Jiatong Yao Min Guo Zhuo Zhang Wei Ren State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China Department of Mechanical Engineering National University of Singapore9 Engineering Drive 1Singapore 117575Singapore State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China Research & Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518057China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Advanced Special Steel Shanghai Key Laboratory of High Temperature SuperconductorsInternational Center for Quantum and Molecular StructuresShanghai UniversityShanghai 200444China

As a 3D printing method,laser powder bed fusion(LPBF)technology has been extensively proven to offer significant advantages in fabricating complex structured specimens,achieving ultra-fine microstructures,and enhancing *** the domain of manufacturing melt-grown oxide ceramics,it encounters substantial challenges in suppressing crack defects during the rapid solidification *** strategic integration of high entropy alloys(HEA),leveraging the significant ductility and toughness into ceramic powders represents a major innovation in overcoming the *** ingenious doping of HEA parti-cles preserves the eutectic microstructures of the Al2O3/GdAlO3(GAP)/ZrO2 ceramic *** high damage tolerance of the HEA alloy under high strain rates enables the absorption of crack energy and alleviation of internal stresses during LPBF,effectively reducing crack initiation and *** to in-creased curvature forces and intense Marangoni convection at the top of the molt pool,particle collision intensifies,leading to the tendency of HEA particles to agglomerate at the upper part of the molt ***,this phenomenon can be effectively alleviated in the remelting process of subsequent layer ***,a portion of the HEA particles partially dissolves and sinks into the molten pool,acting as heterogeneous nucleation particles,inducing the formation of equiaxed eutectic and leading pri-mary phase *** HEA particles diffuse into the lamellar ternary eutectic structures,further promoting the refinement of eutectic microstructures due to increased *** innovative dop-ing of HEA particles has effectively facilitated the fabrication of turbine-structured,conical,and cylindrical ternary eutectic ceramic composite specimens with diameters of about 70 mm,demonstrating significant developmental potential in the field of ceramic composite manufacturing.

关键词： Laser powder bed fusion Eutectic ceramic composite High entropy alloy doping

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Effect of Paddle Mode on Flow Characteristics of a Continuous Stirred Tank Reactor (CSTR) Using CFD Simulations 4th

Effect of Paddle Mode on Flow Characteristics of a Continuou...

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4th International Conference on mechanical Design and Simulation, MDS 2024

作者： Li, Peng Wu, Xuan Cheng, Fuliang Li, Xueqin Research Laboratory of Waste Utilization and Environmental Equipment Development Guangxi University of Science and Technology Liuzhou545006 China School of Mechanical and Automotive Engineering Guangxi University of Science and Technology Liuzhou545006 China

ISBN: (纸本)9789819778867

The efficient stirring is crucial for mixing anaerobic bacteria and substrate in a Continuous Stirred Tank Reactor (CSTR). In this study, we propose a CFD model (Large Eddy Simulation (LES) model) to simulate the reactor’s flow characteristics. The standard turbine paddle modes of the CSTR with different shafts and paddle layers were investigated using XFLOW software. The simulation results reveal that the quantity of shafts and layers has significant influences on the flow characteristics of the reactor. Both single-shaft and double-shaft paddles can provide a complete circulation loop. The mixing performance of single-shaft paddles surpasses that of double-shaft paddles. Moreover, the double layer paddles have better mixing performance than the single layer paddles. Therefore, the most favorable paddle mode for a CSTR is the single shaft paddles with double layers. © The Author(s) 2025.

关键词： Tanks (containers)

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Complete Coverage Path Planning Strategy for Reconfigurable Robot With Variable Footprint

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IEEE Access 2025年 13卷 74446-74456页

作者： Tang, Qinrui Yi, Lim Yaw Sang Wan, Ash Hayat, Abdullah Aamir Vu Le, Anh Rajesh Elara, Mohan Singapore University of Technology and Design ROAR Laboratory Engineering Product Development Pillar Somapah Rd 487372 Singapore United Arab Emirates University Department of Mechanical and Aerospace Engineering Al Ain United Arab Emirates Ton Duc Thang University Faculty of Electrical and Electronics Engineering Communication and Signal Processing Research Group Ho Chi Minh City700000 Viet Nam

Autonomous mobile robots (AMRs) face challenges in navigating complex environments efficiently. To manoeuvre through both narrow and wide spaces, AMRs require two essential design features: a compact form for tight areas as well as a large configuration with omnidirectional movement for wide spaces. This study utilizes inhouse designed Expand and Collapse Variable Width Robot (ECVWR) to demonstrate effective area coverage. These ECVWR can contract to navigate constrained spaces and expand to optimize coverage in open areas. Existing methods for achieving complete area coverage do not account for the reconfiguration or the change in footprint. To address this issue, we propose the Depth-First Search (DFS) for Complete Coverage Path Planning Strategy (CCPPS) for ECVWRs. This method allows adjustments to the generation of waypoints in CCPPS, minimizing the path length. The simulation study shows that our proposed CCPPS outperforms contemporary state-of-the-art CCPPS, namely, GBNN, exhibiting superior expanded area coverage, reduced travel distance, and enhanced computational efficiency. Moreover real-world experiment to further benchmark the efficacy of our proposed algorithm. The proposed CCPPS is generic and can be extended to other variable footprint robots. © 2013 IEEE.

关键词： Robot programming

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A comprehensive 3D-CFD analysis of operational and geometric effects on hydrogen absorption in MH reactor equipped with finned and tubular heat exchangers

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International Journal of Hydrogen Energy 2025年 135卷 553-570页

作者： Bammoune, Abdelaziz Laouedj, Samir Dadda, Bachir Boukhari, Ali Bouali, Belkacem Laboratory of Materials and Reactive Systems Faculty of Technology Djillali Liabes University of Sidi Bel-Abbés Algeria Applied Research Unit for Renewable Energies URAER Renwable Energy Development Center CDER Ghardaïa47133 Algeria Mechanical Engineering Department Faculty of Technology El-Oued University Algeria Process Engineering Laboratory Laghouat University Laghouat Algeria

The chemisorption storage of hydrogen within metal hydride (MH) reactors is considered as the promising method for the successful emergence of hydrogen energy in mobility sector. However, there are two major areas that require attention for this process to be optimized: thermal management and gravimetric storage capacity of MH reactors system. In order to address these challenges, we propose a new cylindrical MH reactor tank design that is filled with 1.58 Kg of LaNi5 powder. To optimize heat and mass transfer during the exothermic hydrogen absorption reaction, we integrate two new heat exchangers containing heat transfer fluid (HTF), which have minor impacts on the reactor volume and weight. The first is a copper-finned heat exchanger, consisting of four rectangular pipes with six stages of circular fins, with occupied ratio of 17.3 % and 14.7 % in total mass and volume of reactor system, respectively. The second is a tubular heat exchanger jacket with a spiral tube on stainless steel SS316, welded to the peripheral wall of the reactor with ratio of 16.3 % and 15.7 % in total mass and volume of reactor. We conducted a three-dimensional numerical study using CFD code of ANSYS FLUENT software to analyse heat and mass transfers during the hydrogen absorption process. The aim of this study is to assess how operational parameters and the geometric design of the two integrated heat exchangers affect the efficiency of solid hydrogen storage, with a focus on identifying optimization possibilities. The results of our simulation procedure were validated with numerical and experimental data published in the literature, showing good agreement. The obtained results indicate that the absorption reaction kinetics exhibit a greater responsiveness to hydrogen injection pressure in comparison to the effect of temperature and the velocity of HTF. Inserting fins through the cooling fluid medium has a dual impact on the heat absorbed by the HTF, increasing its amount and accelerating i

关键词： Fins (heat exchange)

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Influence of Advanced Welding Techniques on the Evolution of Microstructure and mechanical Properties of 2.25Cr-1Mo Steel 4th

Influence of Advanced Welding Techniques on the Evolution of...

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4th International Conference on Recent Advancements in mechanical engineering, ICRAME 2023

作者： Sunilkumar, D. Vasudevan, M. Meshram, Suresh D. Muthukumaran, S. Department of Mechanical Engineering National Institute of Technology Silchar Silchar788010 India Materials Development and Technology Division IGCAR Kalpakkam603102 India Defence Metallurgical Research Laboratory Hyderabad500058 India Department of Metallurgical and Materials Engineering NIT Trichy Tiruchirappalli620015 India

ISBN: (纸本)9789819741663

The aim of the present study is to reduce the width of the heat affected zone of the 2.25Cr-1Mo steel weldment by introducing the friction stir welding process. In FSW process, the tool rpm is the deciding factor for the evolution of peak temperature and cooling rate, which decides the HAZ width. Consequently, the FSW process was carried out with two different tool rpm via 200 and 500 rpm. Microstructural evolution and mechanical properties of the FSW weldment are studied in detail and compared to that of the A-TIG welded joint. The FSW weld metal exhibited higher hardness (405 ± 3HV0.2 for 500 rpm and 370 ± 3HV0.2 for 200 rpm) compared to that of the A-TIG weld (325 ± 4HV0.2) due to the substantial grain refinement and martensitic phase transformation. After post-weld heat treatment at 1003 K for an hour, a gradual reduction in the hardness in the weld was observed. The tensile strength of the FSW joint made with the rotational speed of 500 rpm (554 ± 8 MPa) and 200 rpm (545 ± 5 MPa) was more or less equal to that of the A-TIG (552 ± 7 MPa) weldment. Moreover, FSW weldment exhibits lower HAZ width compared to A-TIG weld. Based on this study, it is recommended that the FSW process employing W-La2O3 tool can be successfully employed as an alternative technique for fusion welding of 2.25Cr-1Mo steel. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Tensile strength

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Phenomenological modeling of plasma-assisted methane ignition using plasma energy fraction manifolds

Phenomenological modeling of plasma-assisted methane ignitio...

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AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2025

作者： Noah Johnson, Praise Taneja, Taaresh Sanjeev Sun, Zongxuan Yang, Suo Kim, Kenneth S. Kweon, Chol-Bum M. Department of Mechanical Engineering University of Minnesota - Twin Cities MinneapolisMN55455 United States U.S. Army Combat Capabilities Development Command Army Research Laboratory Aberdeen Proving GroundMD21005 United States

ISBN: (数字)9781624107238

ISBN: (纸本)9781624107238

The present work advances a phenomenological plasma-assisted combustion model by implementing spatiotemporally varying plasma energy fractions for fast gas heating, vibrational energy excitation, and fast chemical dissociation of gas species. This is achieved through a 2D manifold of plasma energy fractions generated for varying reduced electric fields (E/N) and the thermochemical state of the gas mixture, represented by a progress variable, forming a 2D manifold of energy fractions. The manifold is generated using 0D calculations with a detailed chemical mechanism for plasma-assisted combustion of methane at E/N ranging from 100 to 500 Td and progress variable ranging from 0 (fresh gas mixture) to 1 (burned gas mixture), and is integrated into the phenomenological model. Additionally, a spatiotemporally evolving plasma power density (PPD) obtained from 2D detailed plasma simulations for an air discharge is accommodated in the phenomenological model to describe the evolution of the plasma streamer during discharge. This enhanced model is validated against experiments representing plasma discharge and post-discharge ignition kernel evolution. Specifically, the present model is compared against experimental ultra-fast gas heating and O2 dissociation during plasma discharge, in addition to experimental pressure wave and heated channel radius. The present model is then utilized to investigate ignition kernel evolution for a methane-air discharge across a pin-pin discharge configuration. Specifically, the plasma evolution and the evolution of the post-discharge ignition kernel for a stoichiometric methane-air plasma discharge that utilizes the accommodated spatiotemporal PPD are compared against the results obtained using the original phenomenological model. © 2025, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Dissociation

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