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Penetration resistance characteristics of bioinspired helical laminated composite structures against projectile impact 认领 引用
1
作者 Xingyuan Zhang Xin Sun +2 位作者 Longhui Zhang Zhiyu Shao Yongxiang Dong 《Defence Technology（防务技术）》 SCIE EI CAS CSCD 2026年第7期234-249,共16页
Achieving both high strength and toughness in lightweight structural materials under extreme loading conditions remains a core challenge in composite structural design.Inspired by the helicoidal laminated architecture... Achieving both high strength and toughness in lightweight structural materials under extreme loading conditions remains a core challenge in composite structural design.Inspired by the helicoidal laminated architecture of the mantis shrimp's dactyl club,bioinspired helicoidal carbon fiber/epoxy composite laminates with different interlaminar helix angles were designed and fabricated in this study.The penetration resistance characteristics,dynamic response,and energy absorption performance of these laminates under projectile impact were investigated through a combined experimental and numerical approach.The results indicated that the interlaminar helix angle significantly affects the impact resistance of the structure,the 15°configuration achieved a 45%higher energy absorption than the cross-ply configuration,demonstrating superior comprehensive performance.Further analysis revealed that variation in helix angle significantly alters the internal stress distribution,intralaminar axial and transverse stresses induce fiber fracture and matrix cracking,while interlaminar shear stresses drive delamination along helical shear paths,giving rise to a unique multi-mode progressive damage mechanism.These findings elucidate the mechanisms underlying strength and toughness enhancement in helicoidal architectures under projectile impact,highlighting the critical role in enhancing impact resistance and energy dissipation.The results provide valuable guidance for the structural design and performance optimization of high-performance composite materials with promising application potential. 展开更多
关键词 Bioinspired helical structures Projectile impact Penetration resistance mechanism Intralaminar and interlaminar responses
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Design and experimental validation of a low-impact wing locking/release mechanism based on energy conversion strategy 认领 引用
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作者 Yanbing Wang Honghao Yue +5 位作者 Jun Wu Xueting Pan Fei Yang Yong Zhao Jicheng Liu Xue Bai 《Defence Technology（防务技术）》 SCIE EI CAS CSCD 2026年第1期241-256,共16页
Conventional lockingelease mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or at... Conventional lockingelease mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or attitude instability,seriously compromising mission reliability.To address this engineering challenge,this paper proposes a multi-point low-impact lockingelease mechanism based on the mobility model and energy conversion strategy.Through establishing a DOF constraint framework system,this paper systematically analyzes the energy transfer and conversion characteristics during the wing separation process,reveals the generation mechanism of impact loads,and conducts research on low-impact design based on energy conversion strategy.Building on this foundation,a single-point lockingelease mechanism employing parallel trapezoidal key shaft structure was designed,which increases frictional contact time and reduces the energy release rate,thereby achieving low-impact characteristics.The mechanism's performance was validated through physical prototype development and systematic functional testing(including unlocking force,synchronization,and impact tests).Experimental results demonstrate:(1)Under 14 kN preload condition,the maximum unlocking force was only 92.54 N,showing a linear relationship with preload that satisfies the"strong-connection/weak-unlock"design requirement;(2)Wing separation was completed within 46 ms,with synchronization time difference among three separation mechanisms stably controlled within 12-14 ms,proving rapid and reliable operation;(3)The unlocking impact acceleration ranged between 26 and 73 g,below the 100 g design limit,confirming the effectiveness of the energy conversion strategy.The proposed low-impact lockingelease mechanism design method based on energy conversion strategy resolves the traditional challenges of high impact and synchronization deficiencies.The synergistic optimization mechanism of"structural load reduction and performance improvement"provides a highly reliable technical solution for wing separable mechanisms while offering novel design insights for wing connection/separation systems engineering. 展开更多
关键词 Hypersonic vehicle Energy conversion strategy Low-impact Wing separation Lockingelease mechanism
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Design and experimental verification of a large-scale coupled morphing-wing mechanism for hypersonic vehicles 认领 引用
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作者 Yanbing Wang Honghao Yue +5 位作者 Xueting Pan Jun Wu Fei Yang Yong Zhao Xue Bai Jicheng Liu 《Defence Technology（防务技术）》 SCIE EI CAS CSCD 2026年第2期125-141,共17页
Hypersonic morphing vehicle(HMV)can reconfigure aerodynamic geometries in real time,adapting to diverse needs like multi-mission profiles and wide-speed-range flight,spanwise morphing and sweep angle variation are rep... Hypersonic morphing vehicle(HMV)can reconfigure aerodynamic geometries in real time,adapting to diverse needs like multi-mission profiles and wide-speed-range flight,spanwise morphing and sweep angle variation are representative large-scale wing reconfiguration modes.To meet the HMV's need for an increased lift and a lift to drag ratio during hypersonic maneuverability and cruise or reentry equilibrium glide,this paper proposes an innovative single-DOF coupled morphing-wing system.We then systematically analyze its open-loop kinematics and closed-loop connectivity constraints,and the proposed system integrates three functional modules:the preset lockingelease mechanism,the coupled morphing-wing mechanism,and the integrated wing locking with active stiffness control mechanism.Experimental validation confirms stable,continuous morphing under simulated aerodynamic loads.The experimental results indicate:(i)SMA actuators exhibit response times ranging from 18 s to 160 s,providing sufficient force output for wing unlocking;(ii)The integrated wing locking with active stiffness control mechanism effectively secures wing positions while eliminating airframe clearance via SMA actuation,improving the first-order natural frequency by more than 17%;(iii)The distributed aerodynamic loading system enables precise multi-stage follow-up loading during morphing,with the coupled morphing wing maintaining stable,continuous operation under 0-3500 N normal loads and 110-140 N axial force.The proposed single-DOF coupled morphing mechanism not only simplifies and improves structural efficiency but also demonstrates superior performance in locking control,stiffness enhancement,and aerodynamic responsiveness.This establishes a foundational framework for the design of future intelligent morphing configurations and the implementation of flight control systems. 展开更多
关键词 Hypersonic vehicle Coupled morphing wing Lockingelease Active stiffness control Distributed loading
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Electron-induced evolution of dislocation density and morphology in Mg-Y-Nd-Gd-Zr alloy at ultra-low temperature 认领 引用
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作者 Chengqian Huang Zhen Lu +7 位作者 Chao Xu Xiaojun Wang Chengcai Zhang Dekai Liu Bugang Teng Lianmei Wu Fei Li Manman Yi 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2026年第4期118-126,共9页
This study elucidates the non-thermal mechanism of dislocation density reduction in a Mg-Y-Nd-Gd-Zr alloy under continuous electropulsing(6.67-15 A/mm2)at ultra-low temperatures(-150℃ to-196℃)through tripartite c... This study elucidates the non-thermal mechanism of dislocation density reduction in a Mg-Y-Nd-Gd-Zr alloy under continuous electropulsing(6.67-15 A/mm2)at ultra-low temperatures(-150℃ to-196℃)through tripartite characterization and first-principles analysis.Electron backscatter diffraction(EBSD)reveals a 15.2% decrease in geometrically necessary dislocation(GND)density with increasing current,while X-ray line profile analysis(XLPA)confirms the inverse correlation between current intensity and overall defect density.Transmission electron microscopy(TEM)directly visualizes the dissolution of entangled dislocation clusters into isolated lines under high-current treatment(15 A/mm2),corroborating the statistical trends.First-principles calculations demonstrate that localized charge accumulation at defect sites reduces Mg vacancy formation energy by up to 2.8%,lowering lattice resistance to dislocation glide.This charge-state-dependent vacancy proliferation provides a mechanistic link between electron flow and dislocation annihilation.The reduction of vacancy formation energy is a significant factor in the electron-induced dislocation evolution effect at ultra-low temperatures.These findings provide direct evidence for electron-induced dislocation annihilation mechanisms independent of Joule heating,advancing the understanding of electroplasticity in hexagonal close-packed alloys,and providing a novel approach for rapid,non-oxidative microstructural and property tuning of magnesium alloys. 展开更多
关键词 Isolated electric effect Ultra-low temperature Dislocation density and morphology Vacancy formation energy
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ESL-Based MMC Topology Optimization of Thin-Walled Stiffened Structures Under Transient Impact Loading 认领 引用
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作者 Zizhen Guo Gang Chen +2 位作者 Ang Li Xue Bai Weisheng Zhang 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2026年第5期635-653,共19页
This paper presents an explicit topology optimization method based on the equivalent static load(ESL)method for nonlinear topology optimization of thin-walled stiffened structures under impact loading.This method defi... This paper presents an explicit topology optimization method based on the equivalent static load(ESL)method for nonlinear topology optimization of thin-walled stiffened structures under impact loading.This method defines stiffeners as moving morphable components within a Lagrangian geometric framework.By parametrizing geometric characteristics(including reinforcement positions,profiles,and sizes),it enables simultaneous optimization of both topology configurations and geometric layouts.For nonlinear dynamic optimization under impact loads,the ESL method is integrated into the explicit topology optimization framework.Through load equivalence transformation strategy,the complex nonlinear dynamic optimization problem is converted into a series of linear static subproblems,which significantly reduces computational complexity for the design of thin-walled stiffened structures under nonlinear conditions.The proposed method yields optimized design with guaranteed structural dynamic performance with enhanced optimization efficiency.Several numerical examples are presented to demonstrate its effectiveness and engineering applicability. 展开更多
关键词 Thin-walled stiffened structures Impact loading Nonlinear topology optimization Moving morphable component(MMC) Equivalent static load(ESL)
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Location Privacy Protection of Data Elements in ICVs: A Key Update Mechanism for Defending Against Chosen-Ciphertext Attacks 认领 引用
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作者 Lei Wang Hongji Luo +5 位作者 Yong Heng Jingnan Tang Xiaochuan Ju Jianwei An Haitao Xu Xianwei Zhou 《Computers, Materials & Continua》 SCIE EI 2026年第8期1312-1335,共24页
In intelligent connected vehicles(ICVs)system,driving users connect to service providers(SPs)to obtain location-based services(LBS).Users transmit large volumes of encrypted sensitive information related to their itin... In intelligent connected vehicles(ICVs)system,driving users connect to service providers(SPs)to obtain location-based services(LBS).Users transmit large volumes of encrypted sensitive information related to their itineraries to SPs to access value-added services.Attackers may launch chosen-ciphertext attacks(CCA)against SPs by exploiting the malleability of homomorphic encryption.This enables adversaries to infer or steal private key information,thereby threatening the long-term privacy of user data.Furthermore,existing key management technologies in ICVs system predominantly rely on passive defense strategies and suffer from limitations such as single protection mechanisms,delayed updates,and limited adaptability.To address these issues,this paper proposes an adaptive key update security mechanism based on a differential game framework.This mechanism treats the cumulative information leakage of the private key as a contested resource to construct a differential game model.Based on the feedback Nash equilibrium(NE),the mechanism adaptively derives the optimal homomorphic private key update frequency in response to the attack frequency,thereby maximizing the defense benefit.Finally,numerical simulations validate the correctness of the proposed model and demonstrate the effectiveness of the mechanism. 展开更多
关键词 Intelligent connected vehicles(ICVs) data element privacy differential game adaptive key update homomorphic encryption
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Fault-tolerant control of hypersonic morphing vehicle based on the predefined-time disturbance observer 认领 引用
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作者 LI Yiheng ZHANG Wenjie +2 位作者 WANG Mingkai XIA Qunli LIU Yangxin 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2026年第3期1019-1029,共11页
To address the attitude control problem under the uncertainty,external disturbance,and actuator failure,a predefined-time fault-tolerant control method based on a predefined time disturbance observer is proposed.First... To address the attitude control problem under the uncertainty,external disturbance,and actuator failure,a predefined-time fault-tolerant control method based on a predefined time disturbance observer is proposed.First,the dynamics model of hypersonic morphing vehicle(HMV)is established,and the control system is designed as an outer-loop attitude angle control loop and an inner-loop angular rate control loop considering the actuator failure problem.Secondly,a predefined-time disturbance observer is designed to estimate the comprehensive disturbances,and compensate in the control law.By integrating back-stepping control with predefined-time theory,a predefined-time attitude tracking control method is proposed,enabling the convergence time of the attitude tracking error to be designed through a simple parameter.Rigorous Lyapunov function analysis has demonstrated that the attitude tracking error can converge to an arbitrarily small neighborhood around the origin within a predefined time,and all signals in the closedloop system are bounded.Finally,comparative simulations validate the effectiveness of the proposed method. 展开更多
关键词 hypersonic morphing vehicle(HMV) actuator failure predefined-time disturbance observer predefined-time fault-tolerant control
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Adaptive Control of Discrete-time Nonlinear Systems Using ITF-ORVFL 认领 引用 被引量：5
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作者 Xiaofei Zhang Hongbin Ma +1 位作者 Wenchao Zuo Man Luo 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2022年第3期556-563,共8页
Random vector functional ink(RVFL)networks belong to a class of single hidden layer neural networks in which some parameters are randomly selected.Their network structure in which contains the direct links between inp... Random vector functional ink(RVFL)networks belong to a class of single hidden layer neural networks in which some parameters are randomly selected.Their network structure in which contains the direct links between inputs and outputs is unique,and stability analysis and real-time performance are two difficulties of the control systems based on neural networks.In this paper,combining the advantages of RVFL and the ideas of online sequential extreme learning machine(OS-ELM)and initial-training-free online extreme learning machine(ITFOELM),a novel online learning algorithm which is named as initial-training-free online random vector functional link algo rithm(ITF-ORVFL)is investigated for training RVFL.The link vector of RVFL network can be analytically determined based on sequentially arriving data by ITF-ORVFL with a high learning speed,and the stability for nonlinear systems based on this learning algorithm is analyzed.The experiment results indicate that the proposed ITF-ORVFL is effective in coping with nonparametric uncertainty. 展开更多
关键词 Adaptive control initial-training-free online learning algorithm random vector functional link networks
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Laser powder bed fusion of Mg-6Gd-3Y-0.2Zr alloy:Excellent printability,heterogeneous microstructure and dedicated direct aging heat treatment 认领 引用 被引量：5
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作者 Qingchen Deng Jing Luo +9 位作者 Ziyi Liu Qianye Wu Dazhi Liu Lianmei Wu Fei Li Manman Yi Penghuai Fu Yujuan Wu Liming Peng Wenjiang Ding 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2025年第10期4891-4911,共21页
As a universal casting Mg-RE alloy,Mg-6Gd-3Y-Zr(GW63K,wt.%)alloy exhibits superior strength-ductility synergy and holds significant potential for engineering applications.In this study,the GW63K alloy is produced usin... As a universal casting Mg-RE alloy,Mg-6Gd-3Y-Zr(GW63K,wt.%)alloy exhibits superior strength-ductility synergy and holds significant potential for engineering applications.In this study,the GW63K alloy is produced using the laser powder bed fusion(LPBF)additive manufacturing(AM)process for the first time.The printability,microstructure characteristics,and post-heat treatment conditions of the GW63K alloy are systematically investigated.The as-built GW63K samples demonstrate high relative densities exceeding 99.6%and exhibit no macroscopic and microscopic cracking across a wide range of process parameters,indicating excellent printability.An exceptional heterogeneous microstructure is observed in the as-built GW63K alloy,comprising coarse columnar grains,fine equiaxed grains with an average grain size of 21.72μm,uniformly distributed nano-sized Mg24(Gd,Y)5secondary phase,and numerous dislocations.Consequently,the as-built GW63K alloy displays enhanced tensile strengths and ductility compared to the as-cast alloy,with yield strength(YS),ultimate tensile strength(UTS)and elongation(EL)values of 218±4 MPa,284±5 MPa and 11.9±1.6%respectively.Additionally,due to the absence of coarse micron-sized secondary phase,a specific direct aging(T5)heat treatment regime at 200℃for 128 h is optimized for the as-built GW63K alloy to introduce dense and dispersedβ’aging precipitates.This T5 treatment surpasses the conventional solution plus aging(T6)heat treatment in enhancing mechanical properties.The LPBF-T5 GW63K alloy exhibits YS,UTS and EL values of 293±6 MPa,359±4 MPa and 2.9±0.7%,respectively.Notably,the YS of the LPBF-T5 alloy represents the highest value for the GW63K alloy,even surpassing that of the extrusion-T5 alloy.This study indicates that the GW63K alloy is a highly promising material for manufacturing near-net-shape high-strength Mg alloy components with intricate geometries using LPBF. 展开更多
关键词 Laser powder bed fusion(LPBF) Mg-Gd-Y-Zr alloy Printability Heterogeneous microstructure Direct aging heat treatment
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Microstructure and mechanical properties of TIG and LBW welded Mg−8Li−3Al−2Zn−0.5Y alloy 认领 引用
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作者 Jia-wei LU Hong-jie LIU +8 位作者 Lian-mei WU Jia-xin YU Yu-chuan HUANG Jia-wei SUN Guo-hua WU Wen-xia HU Fei LI Jun-feng LI Wen-cai LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2025年第12期4084-4100,共17页
Tungsten inert gas(TIG)welding and laser beam welding(LBW)were employed on as-cast and as-forged Mg−8Li−3Al−2Zn−0.5Y(LAZ832-0.5Y)alloys to investigate their weldability.The microstructure and mechanical properties of ... Tungsten inert gas(TIG)welding and laser beam welding(LBW)were employed on as-cast and as-forged Mg−8Li−3Al−2Zn−0.5Y(LAZ832-0.5Y)alloys to investigate their weldability.The microstructure and mechanical properties of solid solution treated samples were investigated for the purpose of further strength improvement,which were treated at 350℃ for 4 h.The ultimate tensile strength(UTS)and yield strength(YS)of the optimal TIG as-cast alloy welding joint were 159 and 122 MPa,which were obtained under the welding current of 80 A,and were lower than the UTS(184 MPa)and YS(146 MPa)of the optimal LBW as-forged welding joint under the power of 2.1 kW/2.0 kW double-side welding.After the solid solution treatment,on the one hand,the growth ofα-Mg grains in the fusion zone(FZ),heat affected zone(HAZ)and base metal(BM)of both the TIG and LBW welding joints was insignificant.On the other hand,the larger Al2Y phases were still present,while the much smaller white AlLi particles were dissolved into the matrix,leading to the solid solution strengthening of the welding joints.As a result,the UTS and YS of the TIG welding joint respectively increased to 216 and 188 MPa after solid solution treatment,and those of the LBW welding joint only increased to 211 and 160 MPa,respectively. 展开更多
关键词 Mg−Li alloy tungsten inert gas welding laser beam welding microstructure mechanical properties heat treatment
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Effects of flux purification on composition,microstructure and mechanical properties of Mg-9Li-3Al-1Zn alloy 认领 引用
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作者 Jia-wei SUN Shi-hao XU +5 位作者 Yu-chuan HUANG Lian-mei WU Guo-hua WU Wen-xia HU Fei LI Wen-cai LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2025年第9期2859-2873,共15页
The influence of refining flux composition,refining time,refining temperature,and addition amount on the microstructure and mechanical properties of Mg-9Li-3Al-1Zn alloy was investigated with orthogonal experimental d... The influence of refining flux composition,refining time,refining temperature,and addition amount on the microstructure and mechanical properties of Mg-9Li-3Al-1Zn alloy was investigated with orthogonal experimental design.The flux purification process for Mg-Li alloys was optimized and the most effective ternary flux composition was identified.Results indicate that flux purification significantly mitigates Li loss during smelting by forming a protective surface layer that reduces Li oxidation and evaporation.The optimal flux composition is LiCl:LiF:CaF2in a 3:1:2 mass ratio,with a flux addition of 3%,refining temperature of 720°C,and holding time of 10 min.The elongation of alloy improves to 16.2% after refinement,while the enhancement in strength remains marginal. 展开更多
关键词 Mg-Li alloys flux purification refining process microstructure mechanical properties
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Analysis of high precision detection technique based on optical MEMS accelerometer with double gratings 认领 引用
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作者 MA Honghao WANG Xiao +1 位作者 GAO Shan ZHANG Yu 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2025年第5期1335-1341,共7页
A high precision detection technique is analyzed based on the optical micro electro-mechanical system(MEMS)accelerometer with double gratings for noise suppression and scale factor enhancement.The brief sensing model ... A high precision detection technique is analyzed based on the optical micro electro-mechanical system(MEMS)accelerometer with double gratings for noise suppression and scale factor enhancement.The brief sensing model and modulation detection model are built using the phase sensitive detection,and the relationship between stimulated acceleration and system output is given.The schematics of gap modulation and light intensity modulation are analyzed respectively,and the choice of modulation frequency in the optical MEMS accelerometer system is discussed.According to the experimental results,the scale factor is improved from 15.45 V/g with the gap modulation to 18.78 V/g with the light intensity modulation,and the signal to noise ratio is improved from 42.95 dB to 81.73 dB.The overall noise level in the optical MEMS accelerometer is effectively suppressed. 展开更多
关键词 accelerometer optics micro electro-mechanical system(MEMS) noise suppression
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A Survey of Output Feedback Robust MPC for Linear Parameter Varying Systems 认领 引用 被引量：8
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作者 Xubin Ping Jianchen Hu +3 位作者 Tingyu Lin Baocang Ding Peng Wang Zhiwu Li 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2022年第10期1717-1751,共35页
For constrained linear parameter varying(LPV)systems,this survey comprehensively reviews the literatures on output feedback robust model predictive control(OFRMPC)over the past two decades from the aspects on motivati... For constrained linear parameter varying(LPV)systems,this survey comprehensively reviews the literatures on output feedback robust model predictive control(OFRMPC)over the past two decades from the aspects on motivations,main contributions,and the related techniques.According to the types of state observer systems and scheduling parameters of LPV systems,different kinds of OFRMPC approaches are summarized and compared.The extensions of OFRMPC for LPV systems to other related uncertain systems are also investigated.The methods of dealing with system uncertainties and constraints in different kinds of OFRMPC optimizations are given.Key issues on OFRMPC optimizations for LPV systems are discussed.Furthermore,the future research directions on OFRMPC for LPV systems are suggested. 展开更多
关键词 Linear parameter varying(LPV)systems model predictive control(MPC) output feedback robust control
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Simulation design of fuze warhead system of air defense missile at very low altitude 认领 引用 被引量：1
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作者 Qi Zhao Guangyu Du +2 位作者 Bin Zhang Yanbin Zhai Yuruo Shi 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2017年第3期572-584,共13页
A novel simulation method for fuze warhead system (FWS) at very low altitude flight is proposed to solve adaptability issues of the traditional one in the naval battle. Firstly, a simulation system framework is presen... A novel simulation method for fuze warhead system (FWS) at very low altitude flight is proposed to solve adaptability issues of the traditional one in the naval battle. Firstly, a simulation system framework is presented. Then the detailed implementation of a novel general fuze model, a novel sea echo model and a novel warhead dynamic effectiveness power field algorithm including the simulation system are presented. Finally, simulation results show good performance of the proposed method. The proposed method can simulate the echo signal when the complex fuze antennas detect target and the sea at the same time, and can truly reflect the target positions hit by the warhead fragments. The proposed method can solve the existing problems in the FWS simulation system. 展开更多
关键词 fuze warhead system (FWS) simulation fuze warhead matching sea echo fragment trajectory drifting
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Microstructure evolution and strengthening mechanism of electron beam welded dual-phase Mg-8Li-3Al-2Zn-0.5Y alloy 认领 引用
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作者 Lingfan Yi Jiaxin Yu +9 位作者 Lianmei Wu Yangyang Xu Yuchuan Huang Peng Sun Qi Li Wenxia Hu Fei Li Yuyan Tang Guohua Wu Wencai Liu 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2025年第11期5404-5420,共17页
Nearly undamaged joints of electron beam welded(EBW)dual-phase Mg-8Li-3Al-2Zn-0.5Y alloy were achieved with joint coefficients exceeding 95%.All specimens were fractured at the base metal(BM),implying a significant de... Nearly undamaged joints of electron beam welded(EBW)dual-phase Mg-8Li-3Al-2Zn-0.5Y alloy were achieved with joint coefficients exceeding 95%.All specimens were fractured at the base metal(BM),implying a significant departure from conventional fracture modes of welded joints.The fusion zone(FZ)consists of ultrafine acicular α-Mg and equiaxed β-Li,with grain sizes reduced by approximately 90% and 80%,respectively,compared to the base metal.This results in a significant increase in microhardness of about 40%.A unique multiphase mixture was observed in the heat-affected zone(HAZ),which mainly consists of lamellar eutectoid structures,fine precipitates zone,and numerous fine Mg3(Al,Zn)particles.This mixture was transformed from typical Li(Al,Zn)(a common softening phase)undergoing atomic diffusion and solid-state phase transformation during welding.It introduces a synergistic strengthening effect,making the heat-affected zone no longer the weakest part of the joint.This study provides valuable insights into the electron beam welding technology for Mg-Li alloys and offers theoretical support for manufacturing high-quality joints. 展开更多
关键词 Electron beam welding Mg-8Li-3Al-2Zn-0.5Y Microstructure evolution Mechanical properties Strengthening mechanism
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High joint efficiency achieved in ultra-light Mg-Li alloy by electron beam welding with controlled heat input 认领 引用
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作者 Peng Sun Yangyang Xu +13 位作者 Qi Li Yuyan Tang Yang Jin Jiaxin Yu Lingfan Yi Yuchuan Huang Jiawei Sun Lianmei Wu Fei Li Jiyi Dong Changjiang Chen Yonghua Shen Linda Ke Wencai Liu 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2026年第4期223-240,共18页
For ultra-light Mg-Li alloys with a high Li content,fusion welding is a challenge due to the relatively active main alloying elements Mg and Li.In this study,electron beam welding technology was applied for the first ... For ultra-light Mg-Li alloys with a high Li content,fusion welding is a challenge due to the relatively active main alloying elements Mg and Li.In this study,electron beam welding technology was applied for the first time to join 8-mm-thick forged Mg-12Li-3Al-2Zn-1Si-1Y alloy plates.By controlling the heat input,defects in the welded joints and elemental evaporation were minimized.However,for the Mg-12Li-3Al-2Zn-1Si-1Y alloy,the Mg2Si eutectic phase segregates at the fusion-zone grain boundaries during rapid solidification of the molten pool,thereby promoting the precipitation of coarse Mg3(Al,Zn)phases along the boundaries.This segregation weakened intergranular atomic bonding in the fusion zone,leading to reduced deformability.Consequently,tensile fracture of the welded joints occurred in the fusion zone.With increasing heat input,the precipitation ofα-Mg phases around Mg3(Al,Zn)phases at the grain boundaries improved the deformability of the grain boundaries.As the fusion zone and heat-affected zone were strengthened,fracture shifted to the base material,which became the weakest region.Under these conditions(with the heat input ranging from 123.4 to 164.6 J/mm),the joint efficiency exceeded 95%,and the ultimate tensile strength was approximately 280 MPa.When the heat input was further increased,grains in the heat affected zone coarsened,creating a softened zone where fracture occurred.This study provides a theoretical basis for electron beam welding of high-Li-content Mg-Li alloys,and offers a solution for their joining applications. 展开更多
关键词 Electron beam welding High-Li-content Mg-Li alloy Microstructure evolution Fracture and strengthening mechanisms
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Direct thrust test and asymmetric performance of porous ionic liquid electrospray thruster 认领 引用 被引量：12
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作者 Yuntao GUO Wei SUN +4 位作者 Zhenning SUN Zhiwen WU Jianwu HE Chao YANG Ningfei WANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2023年第4期120-133,共14页
In order to meet the demand of CubeSats for low power and high-performance micro-propulsion system,a porous ionic liquid electrospray thruster prototype is developed in this study.1010 conical emitter arrays are fabri... In order to meet the demand of CubeSats for low power and high-performance micro-propulsion system,a porous ionic liquid electrospray thruster prototype is developed in this study.1010 conical emitter arrays are fabricated on an area of 3.24 cm2 by computer numerical control machining technology.The propellant is 1-ethyl-3-methylimidazolium tetrafluoroborate.The over-all dimension of the assembled prototype is 3 cm×3 cm×1 cm,with a total weight of about 15 g(with propellant).The performance of this prototype is tested under vacuum.The results show that it can work in the voltage range of±2.0 kV to±3.0 kV,and the maximum emission current and input power are about 355 lA and 1.12 W.Time of Flight(TOF)mass spectrometry results show that cationic monomers and dimers dominate the beam in positive mode,while a higher proportion of higher-order solvated ion clusters in negative mode.The maximum specific impulse is 2992 s in positive mode and 849 s in negative mode.The thrust is measured in two methods:one is calculated by TOF results and the other is directly measured by high-precision torsional thrust stand.The thrust(T)obtained by these two methods conforms to a certain scaling law with respect to the emis-sion current(Iem)and the applied voltage(Vapp),following the scale of T-IemVapp0.5,and the thrust range is from 2.1 lN to 42.6 lN.Many thruster performance parameters are significantly different in positive and negative modes.We speculate that due to the higher solvation energy of the anion,more solvated ion clusters are formed rather than pure ions under the same electric field.It may help to improve thruster performance if porous materials with smaller pore sizes are used as reservoirs.Although there are still many problems,most of the performance parameters of ILET-3 are good,which can theoretically meet the requirements of CubeSats for micro-propulsion system. 展开更多
关键词 Asymmetric performance Direct thrust test Ionic liquid electrospray thruster Time of flight mass spectrometry Torsional thrust stand
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A study on key technologies of unmanned driving 认领 引用 被引量：19
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作者 Xinyu Zhang Hongbo Gao +3 位作者 Mu Guo Guopeng Li Yuchao Liu Deyi Li 《CAAI Transactions on Intelligence Technology》 2016年第1期4-13,共10页
Although the development of machine intelligence is far from simulating all the cognitive competence of our brains, still it is absolutely possible to peel the driving activity from people＇s cognitive activities and ... Although the development of machine intelligence is far from simulating all the cognitive competence of our brains, still it is absolutely possible to peel the driving activity from people＇s cognitive activities and then make the machine finish some low-level, complicated and lasting driving cognition by simulating our brains. The goal of driving is to replace drivers and free them from boring driving activities. Based on some studies on unmanned driving, this paper summarizes and analyzes the background, significance, research status and key technology of unmanned driving and the research group also introduces some research on brain cognition of driving and sensor placement of intelligent vehicles, which offers more meaningful reference to push the study of unmanned driving. 展开更多
关键词 Unmanned driving Brain cognition of driving Sensor placement Formalization of brain cognition
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Half space object classification via incident angle based fusion of radar and infrared sensors 认领 引用 被引量：3
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作者 HE Zhenyu ZHUGE Xiaodong +3 位作者 WANG Junxiang YU Shihao XIE Yongjun ZHAO Yuxiong 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2022年第5期1025-1031,共7页
In this paper,we introduce an incident angle based fusion method for radar and infrared sensors to improve the recognition rate of complex targets under half space scenarios,e.g.,vehicles on the ground in this paper.F... In this paper,we introduce an incident angle based fusion method for radar and infrared sensors to improve the recognition rate of complex targets under half space scenarios,e.g.,vehicles on the ground in this paper.For radar sensors,convolutional operation is introduced into the autoencoder,a“winner-take-all(WTA)”convolutional autoencoder(CAE)is used to improve the recognition rate of the radar high resolution range profile(HRRP).Moreover,different from the free space,the HRRP in half space is more complex.In order to get closer to the real situation,the half space HRRP is simulated as the dataset.The recognition rate has a growth more than 7%com-pared with the traditional CAE or denoised sparse autoencoder(DSAE).For infrared sensor,a convolutional neural network(CNN)is used for infrared image recognition.Finally,we com-bine the two results with the Dempster-Shafer(D-S)evidence theory,and the discounting operation is introduced in the fusion to improve the recognition rate.The recognition rate after fusion has a growth more than 7%compared with a single sensor.After the discounting operation,the accuracy rate has been improved by 1.5%,which validates the effectiveness of the proposed method. 展开更多
关键词 convolutional autoencoder(CAE) half space high-resolution range profile(HRRP) incident angle based fusion tar-get recognition
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Bayesian optimal design of step stress accelerated degradation testing 认领 引用 被引量：3
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作者 Xiaoyang Li Mohammad Rezvanizaniani +2 位作者 Zhengzheng Ge Mohamed Abuali Jay Lee 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2015年第3期502-513,共12页
This study presents a Bayesian methodology for de- signing step stress accelerated degradation testing （SSADT） and its application to batteries. First, the simulation-based Bayesian de- sign framework for SSADT is p... This study presents a Bayesian methodology for de- signing step stress accelerated degradation testing （SSADT） and its application to batteries. First, the simulation-based Bayesian de- sign framework for SSADT is presented. Then, by considering his- torical data, specific optimal objectives oriented Kullback-Leibler （KL） divergence is established. A numerical example is discussed to illustrate the design approach. It is assumed that the degrada- tion model （or process） follows a drift Brownian motion; the accele- ration model follows Arrhenius equation; and the corresponding parameters follow normal and Gamma prior distributions. Using the Markov Chain Monte Carlo （MCMC） method and WinBUGS software, the comparison shows that KL divergence is better than quadratic loss for optimal criteria. Further, the effect of simulation outiiers on the optimization plan is analyzed and the preferred sur- face fitting algorithm is chosen. At the end of the paper, a NASA lithium-ion battery dataset is used as historical information and the KL divergence oriented Bayesian design is compared with maxi- mum likelihood theory oriented locally optimal design. The results show that the proposed method can provide a much better testing plan for this engineering application. 展开更多
关键词 accelerated testing Bayesian theory KL divergence,degradation optimal design battery.
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