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Robust interface and excellent as-built mechanical properties of Ti–6Al–4V fabricated through laser-aided additive manufacturing with powder and wire

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 154-168页

作者： Fei Weng Guijun Bi Youxiang Chew Shang Sui Chaolin Tan Zhenglin Du Jinlong Su Fern Lan Ng Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong Engineering&Technology Research Center for Superhard MaterialSchool of Materials Science and EngineeringShandong UniversityJinan 250061China institute of Intelligent Manufacturing Guangdong Academy of SciencesGuangzhou 510095China Singapore institute of Manufacturing technology 5 Cleantech Loop636732Singapore

The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully circumvent defects in Ti-6Al-4V deposits for LAAM_(p) and LAAM_(w),*** the optimized process parameters,robust interfaces were achieved between powder/wire deposits and the forged substrate,as well as between powder and wire *** characterization results revealed the epitaxial prior β grains in the deposited Ti-6Al-4V,wherein the powder deposit was dominated by a finerα′microstructure and the wire deposit was characterized by lamellar α *** mechanisms of microstructure formation and correlation with mechanical behavior were analyzed and *** mechanical properties of the interfacial samples can meet the requirements of the relevant aerospace Material Specifications(AMS 6932)even without post heat *** fracture occurred within the interfacial area,further suggesting the robust *** findings of this study highlighted the feasibility of combining LAAM_(p) and LAAM_(w) in the direct manufacturing of Ti-6Al-4V parts in accordance with the required dimensional resolution and deposition rate,together with sound strength and ductility balance in the as-built condition.

关键词： laser-aided additive manufacturing powder deposition wire deposition interfacial characteristic mechanical behavior

Three-dimensional fracture of UO2 ceramic pellets by phase field modeling

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science china(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 169-180页

作者： Wei Xiong Xuan Ye Hongzhang Cheng Xiaoming Liu institute of Nuclear and New Energy technology Collaborative Innovation Center of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Tsinghua University State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences School of Engineering science University of Chinese Academy of Sciences

Fracture is the primary failure type for the UO2ceramic pellets,which are operated under irradiation and thermal processes,and physically confined by the *** this work,by combining closely coupled physical processes of heat conduction,heat transfer,and mechanical deformation with the cohesive phase field framework,we proposed a high-precision modeling of quasistatic cracking of three-dimensional （3D） UO2ceramic fuel pellets under high temperature and *** simulation results agree well with the experimental results,indicating that the proposed method has the potential to capture 3D crack modes in the interested time ***,we studied the relation of the 3D fracture patterns of fuel pellets with the peak power *** was found that the power level plays a critical role in determining the competition between radial and circumferential cracks,as well as transverse penetrating cracks.

关键词： phase field method nuclear fuel pellet coupled thermo-mechanical model thermal fracture

Discrete decision model and multi-agent simulation of the Liang Zong two-chain hierarchical organization in a complex project

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Journal of Systems Engineering and Electronics 2018年第2期29卷 311-320页

作者： MAI Qiang ZHAO Yueqiang AN Shi School of Management Harbin Institute of Technology Defense technology academy China Aerospace Science & Industry Corporation

Different from the organization structure of complex projects in Western countries, the Liang Zong hierarchical organization structure of complex projects in china has two different chains, the chief-engineer chain and the general-director chain,to handle the trade-off between technical and management decisions. However, previous works on organization search have mainly focused on the single-chain hierarchical organization in which all decisions are regarded as homogeneous. The heterogeneity and the interdependency between technical decisions and management decisions have been neglected. A two-chain hierarchical organization structure mapped from a real complex project is constructed. Then, a discrete decision model for a Liang Zong two-chain hierarchical organization in an NK model framework is proposed. This model proves that this kind of organization structure can reduce the search space by a large amount and that the search process should reach a final stable state more quickly. For a more complicated decision mechanism, a multi-agent simulation based on the above NK model is used to explore the effect of the two-chain organization structure on the speed, stability, and performance of the search process. The results provide three insights into how, compared with the single-chain hierarchical organization, the two-chain organization can improve the search process: it can reduce the number of iterations efficiently; the search is more stable because the search space is a smoother hill-like fitness landscape; in general, the search performance can be ***, when the organization structure is very complicated, the performance of a two-chain organization is inferior to that of a single-chain organization. These findings about the efficiency of the unique Chinese-style organization structure can be used to guide organization design for complex projects.

关键词： complex project two-chain hierarchical organization discrete decision model multi-agent simulation

Nonlinear dynamics of fixed-trim reentry vehicles with moving-mass roll control system

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Journal of Systems Engineering and Electronics 2016年第6期27卷 1249-1261页

作者： Yafei Wang Jianqiao Yu Yuesong Mei Linlin Wang Xiaolong Su School of aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Beijing institute of Space Long March Vehicle Beijing 100076China The 41st institute of fourth academy of aerospace science and technology corporation Xi’an 710025China

Nonlinear dynamic characteristics of a fixed-trim reentry vehicle controlled by an internal moving-mass actuator are analyzed. A traditional dynamic model develops into a five-dimensional nonlinear model using classic Euler angles and their derivatives as state variables. Based on the nonlinear motion equations, by setting the offset distance of the moving-mass as a variation parameter, the curves of the system's equilibrium points are presented by numerical methods. Then the distributions and approximate analytical solutions of the equilibrium points are obtained by simplifying the model under the condition of small intrinsic angles. The results show that the numbers and values of the equilibrium points are closely connected with the location of the moving-mass. Furthermore, the stabilities of equilibrium points are examined by the Lyapunov's first method and three groups of stable equilibrium points are obtained. Since only one group of the stable equilibrium points is desired, the angular motion of the system may be unstable or stay in an undesired lock-in state when the offset distance of the moving-mass or the attitude disturbance of the vehicle is too large. © 2016 Beijing institute of aerospace Information.

关键词： Dynamics Equations of motion Numerical methods Reentry Vehicles

Mechanical Properties of Railway High-strength Manufactured Sand Concrete:Typical Lithology,Stone Powder Content and Strength Grade

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Journal of Wuhan University of technology(Materials science) 2025年第1期 194-203页

作者：王振李化建 HUANG Fali YANG Zhiqiang WEN Jiaxin SHI Henan Railway Engineering Research institute China Academy of Railway Science Corporation Limited State Key Laboratory for Track technology of High-Speed Railway

In order to achieve the large-scale application of manufactured sand in railway high-strength concrete structure,a series of high-strength manufactured sand concrete (HMC) are prepared by taking the manufactured sand lithology (tuff,limestone,basalt,granite),stone powder content (0,5%,10%,15%) and concrete strength grade (C60,C80,C100) as *** evolution of mechanical properties of HMC and the correlation between cubic compressive strength and other mechanical properties are *** to river sand,manufactured sand enhances the cubic compressive strength,axial compressive strength and elastic modulus of concrete,while its potential microcracks weaken the flexural strength and splitting tensile strength of *** powder content displays both positive and negative effects on mechanical properties of HMC,and the stone powder content is suggested to be less than 10%.The empirical formulas between cubic compressive strength and other mechanical properties are proposed.

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Damage-ignition mechanism studies on modified propellant with different crosslinking density under dynamic loading

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Defence technology（防务技术） 2023年第10期28卷 155-164页

作者： Hong-zheng Duan Yan-qing Wu Xiao Hou Kun Yang Feng-lei Huang State Key Laboratory of Explosion science and technology Beijing Institute of TechnologyBeijing100081PR China School of aerospace Engineering Beijing Institute of TechnologyBeijing100081PR China The fourth institute of china aerospace science and technology corporation Xi'an710025PR China

The study of high-energy and low-vulnerability propellants is important for the power performance and safety of solid propellant rocket *** modified split Hopkinson pressure bar(SHPB)tests are performed on two kinds of propellant with different crosslinking density to study the dynamic mechanical responses and damage-ignition *** apparatus is equipped with a highperformance infrared camera and high-speed camera to capture the deformation,damage-ignition feature and temperature evolution images in the impact *** results suggested that the mechanical responses and damage-ignition mechanism of the propellants were affected by the strain rates and crosslinking *** damage-ignition degree is more intense and the reaction occurs earlier with the increase of strain *** propellant 1 with higher crosslinking density,the critical ignition strain rate is 4500 s^(-1).Two kinds of propellants show different ignition mechanism,*** generation,propagation and final fracture for propellant 1 while viscous shear flow for propellant ***,the SEM images also reveal the difference of damage-ignition mechanism of the two kinds of ***,the ignition mechanism under different strain rates and critical ignition strain rate of propellants are further explained by the theoretical calculation of temperature variations.

关键词： The modified propellants Dynamic loading Mechanical property Damage-ignition mechanism Experimental and theoretical calculation

Effect of neutral polymeric bonding agent on tensile mechanical properties and damage evolution of NEPE propellant

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Defence technology（防务技术） 2024年第2期32卷 357-367页

作者： M.Wubuliaisan Yanqing Wu Xiao Hou Kun Yang Hongzheng Duan Xinmei Yin State Key Laboratory of Explosion science and technology Beijing Institute of TechnologyBeijing100081PR China The fourth institute of china aerospace science and technology corporation Xi'an710025PR China School of aerospace Engineering Beijing Institute of TechnologyBeijing100081PR China science and technology on aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechnologyHubei441003PR China

Introducing Neutral Polymeric bonding agents(NPBA) into the Nitrate Ester Plasticized Polyether(NEPE)propellant could improve the adhesion between filler/matrix interface, thereby contributing to the development of new generations of the NEPE propellant with better mechanical properties. Therefore,understanding the effects of NPBA on the deformation and damage evolution of the NEPE propellant is fundamental to material design and applications. This paper studies the uniaxial tensile and stress relaxation responses of the NEPE propellant with different amounts of NPBA. The damage evolution in terms of interface debonding is further investigated using a cohesive-zone model(CZM). Experimental results show that the initial modulus and strength of the NEPE propellant increase with the increasing amount of NPBA while the elongation decreases. Meanwhile, the relaxation rate slows down and a higher long-term equilibrium modulus is reached. Experimental and numerical analyses indicate that interface debonding and crack propagation along filler-matrix interface are the dominant damage mechanism for the samples with a low amount of NPBA, while damage localization and crack advancement through the matrix are predominant for the ones with a high amount of NPBA. Finally, crosslinking density tests and simulation results also show that the effect of the bonding agent is interfacial rather than due to the overall crosslinking density change of the binder.

关键词： Solid propellant Bonding agent Mechanical properties Damage evolution Cohesive-zone model Interface debonding

Numerical simulations of gas-particle flow behavior created by low-level rotary-winged aircraft flight over particle bed

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Applied Mathematics and Mechanics(English Edition) 2019年第3期40卷 397-406页

作者： Xiaoxue JIANG Yingqiao XU Chuang WANG Linzhi MENG Huilin LU School of Energy science and Engineering Harbin Institute of Technology Fifth Research institute China Aerospace Science and Technology Corporation

The aerodynamics of gas-particle suspensions is simulated as an Euler-Euler two-fluid model in a revolving rotor over a particle bed. The interactions of collisions between the blade and particles and particle-particle interactions are modeled using the kinetic theory of granular flow(KTGF). The gas turbulence induced by the rotation of the rotor is modeled using the kg-εg model. The flow field of a revolving rotor is simulated using the multiple reference frame(MRF) method. The distributions of velocities, volume fractions, and gas pressure are predicted while the aircraft hovers at different *** gas pressure decreases from the hub to the tip of the blade, and it is higher at the pressure side than that at the suction side of the rotor. The turbulent kinetic energy of the gas increases toward the blade tip. The volume fraction of particles decreases as the hovering altitude increases. The simulated pressure coefficient is compared with that in experimental measurements.

关键词： helicopter rotor Euler-Euler two-fluid model kinetic theory of granular flow(KTGF) pressure coefficient

Technological breakthroughs and scientific progress of the Chang'e-4 mission

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science china(Information sciences) 2020年第10期63卷 5-18页

作者： Weiren WU Dengyun YU Chi WANG Jizhong LIU Yuhua TANG He ZHANG Zhe ZHANG Lunar Exploration and Space Engineer Center china aerospace science and technology corporation National Space science Center Chinese Academy of Sciences institute of Spacecraft System Engineer China Academy of Space Technology

Chang’e-4 is the first man-made probe that accomplished landing and roving on the far side of the Moon, which is viewed as a new milestone in the history of Lunar exploration. Beginning with a brief introduction to the progress of domestic and foreign Lunar exploration, this paper reviews the implementation process of the Chang’e-4 project, sorts out the technical breakthroughs achieved, summarizes the exploration achievements, and provides references for subsequent Lunar exploration.

关键词： Chang’e-4 Moon’s far side soft landing Earth-Moon L2 point relay satellite technological breakthrough scientific achievement