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An improved efficient adaptive method for large-scale multiexplosives explosion simulations

Defence technology(防务技术) 2025年第3期45卷 28-47页

作者： Tao Li Cheng Wang Baojun Shi School of Mechanical Engineering Key Laboratory of Advanced Intelligent Protective Equipment TechnologyMinistry of EducationHebei University of TechnologyTianjin300401China State Key Lab of Explosion Science and Safety Protection Beijing Institute of TechnologyBeijing 100081China

Shock wave caused by a sudden release of high-energy,such as explosion and blast,usually affects a significant range of *** utilization of a uniform fine mesh to capture sharp shock wave and to obtain precise results is inefficient in terms of computational *** is particularly evident when large-scale fluid field simulations are conducted with significant differences in computational domain *** this work,a variable-domain-size adaptive mesh enlargement(vAME)method is developed based on the proposed adaptive mesh enlargement(AME)method for modeling multi-explosives explosion *** vAME method reduces the division of numerous empty areas or unnecessary computational domains by adaptively suspending enlargement operation in one or two directions,rather than in all directions as in AME method.A series of numerical tests via AME and vAME with varying nonintegral enlargement ratios and different mesh numbers are simulated to verify the efficiency and order of *** estimate of speedup ratio is analyzed for further efficiency *** large-scale near-ground explosion experiments with single/multiple explosives are performed to analyze the shock wave superposition formed by the incident wave,reflected wave,and Mach ***,the vAME method is employed to validate the accuracy,as well as to investigate the performance of the fluid field and shock wave propagation,considering explosive quantities ranging from 1 to 5 while maintaining a constant total *** results show a satisfactory correlation between the overpressure versus time curves for experiments and numerical *** vAME method yields a competitive efficiency,increasing the computational speed to 3.0 and approximately 120,000 times in comparison to AME and the fully fine mesh method,*** indicates that the vAME method reduces the computational cost with minimal impact on the results for such large-scale high-energy release problems with signi

关键词： Large-scale explosion Shock wave Adaptive method Fluid field simulations Efficient method

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Revealing effects of powder reuse for LPBF-fabricated NiTi shape memory alloys

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Frontiers of Materials Science 2024年第4期18卷 191-201页

作者： Xiang Li Meng Zhou Sihui Peng Xiaonan Chen Xueyuan Ge Bingmin Huang Lishan Cui Shijie Hao College of New Energy and Materials China University of PetroleumBeijing 102249China State Key Laboratory of Advanced Forming Technology and Equipment China Machinery Institute of Advanced Materials Co.Ltd.Zhengzhou 450001China Jiangsu Smart Advanced Material Technology Co. Ltd.Xuzhou 221000China

In metal-based additive manufacturing processes,such as laser powder bed fusion(LPBF),the powder utilization is often less than 50%.Considering the cost efficiency,powder reuse is needed for an economical and sustainable LPBF *** intermetallic compounds,LPBF-fabricated NiTi alloys are characterized with phase transformation behaviors,mechanical properties and functions that are very sensitive to possible changes in powder characteristics caused through reuse,but the exact effects are still poorly ***,the LPBF process has been repeated ten times using the virgin powder supplement *** show that the oxygen content of NiTi powders rises from 370 to 752.3 ppm with the enhancement of the reuse cycle *** oxidation enhances the laser absorptivity of the powder bed,leading to an increase in surface roughness and porosity of NiTi *** to the specimens made from virgin powders,the mechanical property and shape memory function of specimens made from reused powders are degraded,mainly attributed to the oxygen impurity and deteriorated forming *** study allows making better decisions with regard to powder reuse in the development of performance-critical NiTi parts fabricated through LPBF.

关键词： laser powder bed fusion NiTi shape memory alloy powder reuse microstructure mechanical property

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Corrosion behavior of Gd_(2)Zr_(2)O_(7)thermal barrier coatings under Fe-containing environmental sediment attack

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Journal of advanced Ceramics 2024年第4期13卷 447-462页

作者： Lei Guo Yanyan Li Kai Yan School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Advanced Joining Technology Key Lab of Advanced Ceramics and Machining Technology of Ministry of EducationTianjin 300072China Key Laboratory of Special Equipment Safety and Energy-saving for State Market Regulation China Special Equipment Inspection&Research InstituteBeijing 100029China

Environmental sediments mainly consisting of CaO–MgO–Al_(2)O_(3)–SiO_(2)(CMAS)corrosion are a serious threat to thermal barrier coatings(TBCs),in which Fe element is usually ***_(2)Zr_(2)O_(7)TBCs are famous for their excellent CMAS *** this study,the characteristics of Fe-containing environmental sediments(CMAS-Fe)and their corrosiveness to Gd_(2)Zr_(2)O_(7)coatings were *** types of CMAS-Fe glass with different Fe contents were *** melting points were measured to be 1322–1344℃,and the high-temperature viscosity showed a decreasing trend with increasing Fe *** corrosion behavior of four types of CMAS-Fe to Gd_(2)Zr_(2)O_(7)coatings at 1350℃was *** the initial corrosion stage(0.1 h),anorthite was precipitated in CMAS-Fe with a high Ca:Si ratio,while Fe-garnet was formed in the melt with the highest Fe *** the corrosion time resulted in the formation of a reaction layer,which exhibited an interpenetrating network composed of Gd-oxyapatite,ZrO_(2),and residual *** spinel was precipitated within the reaction *** 1 h or even longer time,the reaction layers tended to be stable and compact,which had comparable hardness and fracture toughness to those of Gd_(2)Zr_(2)O_(7)*** the cyclic CMAS-Fe attack,the residual CMAS-Fe in the interpenetrating network provided a pathway for the redeposited CMAS-Fe infiltration,resulting in the continuous growth of the reaction *** a result,the Gd_(2)Zr_(2)O_(7)coatings had a large consumption in the thickness,degrading the coating ***,the Gd_(2)Zr_(2)O_(7)coatings exhibit unsatisfactory corrosion resistance to CMAS-Fe attack.

关键词： thermal barrier coatings(TBCs) Gd_(2)Zr_(2)O_(7) Fe-containing CaO-MgO-Al2O3-SiO_(2)(CMAS) corrosion resistance reaction layer

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Determination of interfacial heat transfer coefficient at the frozen sand mold casting process of ZL101 alloy

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Journal of Materials Science & technology 2024年第27期194卷 28-42页

作者： Shijie Dong Zhongde Shan Feng Lin Haoqin Yang Xiao Liang Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and TechnologyBeijing 100037China Key Laboratory for Advanced Materials Processing Technology Ministry of Education of ChinaBeijing 100084China College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Material Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Compared to the resin sand mold casting process, frozen casting is more environmentally friendly, providing a better working environment and enhanced supercooling degree. The interfacial heat transfer coefficient (IHTC) between frozen sand mold and metal is an important parameter that significantly influences the final mechanical properties and microstructure of the castings. This paper solved the inverse heat conduction problem using the finite difference method (FDM). In addition, the conjugate gradient method (CGM) was adopted to calculate the temperature distribution and heat flux in the molten metal. At the same time, the particle swarm optimization algorithm (PSO) was used in temperature distribution determination in frozen sand mold. The interfacial heat transfer coefficient (IHTC) was estimated during the solidification of ZL101. The results showed a good agreement between calculated and experimental data, obtaining accurate casting interface temperature Tm, frozen sand mold interface temperature Ts, heat flux q, and IHTC. The analysis of the IHTC variation revealed a water content value within the range of 4 wt.% to 5 wt.% resulted in IHTC in two types of interpretation, called ‘fluctuation type’ and ‘turning type’.

关键词： Frozen sand mold Interfacial heat transfer coefficient(IHTC) Finite difference method(FDM) Conjugate gradient method(CGM) Particle swarm optimization(PSO)

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Significant reduction of anisotropy in stress relaxation aging and mechanical properties improvement for 2195 Al-Cu-Li alloy subjected to plastic loading

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Chinese Journal of Aeronautics 2025年第1期38卷 217-234页

作者： Liwen ZHANG Heng LI Tianjun BIAN Changhui WU Yanfeng YANG State Key Lab of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Xi’an Aeronautical Polytechnic Institute Xi’an 710089China Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment Northwestern Polytechnical UniversityXi’an 710072China

Although the plastic loading can enhance creep deformation and yield strength,the anisotropic Stress Relaxation Aging(SRA)behavior and mechanism under plastic loading remain unclear,which presents a significant challenge in accurately shaping aluminum alloy *** this study,the SRA behavior of 2195-T4 Al-Cu-Li alloys were thoroughly studied under initial loading stresses within the elastic(210/250 MPa)and plastic(380/420 MPa)ranges at 180℃by stress relaxation and tensile tests as well as microstructure *** findings reveal that compared with those under elastic loadings,in-plane anisotropy(IPA)values of the stress relaxation amount,yield strength and fracture elongation under plastic loadings are reduced by 60%–80%,70%–90% and 72%–89%,***,IPA values of precipitate size in grains and PrecipitationFree Zones(PFZ)width at grain boundaries under plastic loading decrease by 31.4%and 94.4%*** results indicate plastic loading significantly weakens the anisotropic SRA behavior,owing to numerous uniformly distributed fine T1phases and small IPA values of both T1precipitates size and PFZ width in various loading *** with those of elastic loadingaged alloys,yield strength of plastic loading-aged alloys shows high strength-ductility because of the combined effect of closely dispersed fine T1precipitates,narrowed PFZ and numerous sheared and rotated T1phases at different locations during tensile *** uniformly distributed larger Kernel Average Misorientation(KAM)and Schmidt factor values of the plastic loading-aged alloy,as well as the cross-slip generated,also help to enhance the strength and ductility of the alloy.

关键词： Aluminum-lithium alloy Stress relaxation aging Precipitation-free zones In-plane anisotropy Stress relaxation

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Application of Rapid Manufacturing Process & equipment System for Large Complex Light Alloy Structural Components 75

Application of Rapid Manufacturing Process & Equipment Syste...

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75th World Foundry Congress, WFC 2024

作者： Hong, Haichun State Key Laboratory of Advanced Forming Technology and Equipment Beijing National lnnovation Institute of Lightweight Ltd. Beijing China

This paper introduces the key technologies of light alloy fire-retardant sand printing and forming processes, including material system optimization, feedstock ratios, mixing methods, and in-house developed additive manufacturing equipment. Through the shape-controllable composite mold technology, the challenges of matching and precise regulation between mold and casting properties have been addressed, enabling rapid manufacturing through mold-less composite forming. The impact of multi-material composite molds on the performance of castings has been investigated, leading to the invention of corresponding control principles and assembly methods. Furthermore, addressing the influence of sand parameters on forming quality and tool wear, formulas comprising materials such as quartz sand, zircon sand, and chromite sand have been devised, achieving synergistic optimization of mold properties. Finally, for future needs, ceramic core additive manufacturing equipment has been developed to further advance material forming technology. © 2024 75th World Foundry Congress, WFC 2024. All rights reserved.

关键词： Foundry sand

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Finite element simulation of wear-resistant steel ball forging process 5

Finite element simulation of wear-resistant steel ball forgi...

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2024 5th International Conference on advanced Materials and Intelligent Manufacturing, ICAMIM 2024

作者： Pan, Peng Ge, Feng Yang, Ming Yu, Jinxi Zuo, Lingli Beijing National Innovation of Lightweight Ltd. Beijing101400 China State Key Laboratory for Advanced Forming Technology and Equipment China Academy of Machinery and Technology Beijing101400 China

Deform-3D software was used to analyse the forming characteristics of wear-resistant steel balls, material fluidity, stress-strain distribution, load-time curve, and break coefficient of three kinds of forging billets in the forging process. It was concluded that with the reduction of the height of the original billet, the damage coefficient of the middle position of the billet decreased during the final stage of billet forming. The forging ratio of the blank should be appropriately reduced to reduce the risk of forming defects in the forging process. 2025 Published under licence by IOP Publishing Ltd.

关键词： Billets (metal bars)

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Effect of tempering temperature on microstructure and mechanical properties of 4Cr13VTi steel 9

Effect of tempering temperature on microstructure and mechan...

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2023 9th International Forum on Manufacturing technology and Engineering Materials, ICMTEM 2023

作者： Pan, Peng Wang, Jinnan Yang, Ming Beijing National Innovation of Lightweight Ltd. Beijing101400 China State Key Laboratory for Advanced Forming Technology and Equipment China Academy of Machinery and Technology Beijing101400 China

To optimize the tempering process of 40Cr13VTi steel containing V and Ti, the effect of tempering temperature on microstructure, precipitation, and properties of 40Cr13VTi stainless steel has been studied. Optical microscope (OM), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS) were used to analyze microstructure and precipitates. Tensile, impact, and hardness testing tests were performed to test the mechanical properties of 40Cr13VTi martensitic stainless steel. The research results indicate that as the increase of tempering temperature, the carbides precipitated gradually increase, and the shape gradually changes from particle to flake, which is consistent with the direction of the original martensite flat surface, and most of them concentrate at the martensite boundary. When the tempering temperature is 350°C, 40Cr13VTi martensitic stainless steel obtains the best comprehensive properties, strength, impact toughness (IT), and hardness which are 1360 MPa, 1717 MPa, 8.5 J/cm2, and 45.1 HRC respectively. © Published under licence by IOP Publishing Ltd.

关键词： Martensite

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Data-driven casting defect prediction model for sand casting based on random forest classification algorithm

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china Foundry 2024年第2期21卷 137-146页

作者： Bang Guan Dong-hong Wang Da Shu Shou-qin Zhu Xiao-yuan Ji Bao-de Sun Shanghai Key Lab of Advanced High-Temperature Materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Lab of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China Hefei Casting and Forging Factory of Anhui Heli Co. LtdHefei 230000China State Key Laboratory of Materials Processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan 430074China

The complex sand-casting process combined with the interactions between process parameters makes it difficult to control the casting quality,resulting in a high scrap rate.A strategy based on a data-driven model was proposed to reduce casting defects and improve production efficiency,which includes the random forest(RF)classification model,the feature importance analysis,and the process parameters optimization with Monte Carlo *** collected data includes four types of defects and corresponding process parameters were used to construct the RF *** results show a recall rate above 90% for all *** Gini Index was used to assess the importance of the process parameters in the formation of various defects in the RF ***,the classification model was applied to different production conditions for quality *** the case of process parameters optimization for gas porosity defects,this model serves as an experimental process in the Monte Carlo method to estimate a better temperature *** prediction model,when applied to the factory,greatly improved the efficiency of defect *** show that the scrap rate decreased from 10.16% to 6.68%.

关键词： sand casting process data-driven method classification model quality prediction feature importance

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AI-driven 3D bioprinting for regenerative medicine:From bench to bedside

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Bioactive Materials 2025年第3期45卷 201-230页

作者： Zhenrui Zhang Xianhao Zhou Yongcong Fang Zhuo Xiong Ting Zhang Biomanufacturing Center Department of Mechanical EngineeringTsinghua UniversityBeijing100084PR China Biomanufacturing and Rapid Forming Technology Key Laboratory of Beijing Beijing100084PR China “Biomanufacturing and Engineering Living Systems”Innovation International Talents Base(111 Base) Beijing100084PR China State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing100084PR China

In recent decades,3D bioprinting has garnered significant research attention due to its ability to manipulate biomaterials and cells to create complex structures ***,due to technological and cost constraints,the clinical translation of 3D bioprinted products(BPPs)from bench to bedside has been hindered by challenges in terms of personalization of design and scaling up of ***,the emerging applications of artificial intelligence(AI)technologies have significantly improved the performance of 3D ***,the existing literature remains deficient in a methodological exploration of AI technologies’potential to over-come these challenges in advancing 3D bioprinting toward clinical *** paper aims to present a systematic methodology for AI-driven 3D bioprinting,structured within the theoretical framework of Quality by Design(QbD).This paper commences by introducing the QbD theory into 3D bioprinting,followed by sum-marizing the technology roadmap of AI integration in 3D bioprinting,including multi-scale and multi-modal sensing,data-driven design,and in-line process *** paper further describes specific AI applications in 3D bioprinting’s key elements,including bioink formulation,model structure,printing process,and function ***,the paper discusses current prospects and challenges associated with AI technologies to further advance the clinical translation of 3D bioprinting.

关键词： 3D bioprinting Artificial intelligence Machine learning Quality by design Regenerative medicine Clinical translation

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