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Stress-assisted corrosion mechanism of 3Ni steel by using gradient boosting decision tree machining learning method

International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1311-1321页

作者： Xiaojia Yang Jinghuan Jia Qing Li Renzheng Zhu Jike Yang Zhiyong Liu Xuequn Cheng Xiaogang Li institute of Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China AECC Key Laboratory of Advanced Corrosion and Protection of aeronautical Materials AECC Beijing Institute of Aeronautical MaterialsBeijing 100095China Shunde Innovation School University of Science and Technology BeijingFoshan 528399China

Traditional 3Ni weathering steel cannot completely meet the requirements for offshore engineering development,resulting in the design of novel 3Ni steel with the addition of microalloy elements such as Mn or Nb for strength enhancement becoming a *** stress-assisted corrosion behavior of a novel designed high-strength 3Ni steel was investigated in the current study using the corrosion big data *** information on the corrosion process was recorded using the galvanic corrosion current monitoring *** gradi-ent boosting decision tree(GBDT)machine learning method was used to mine the corrosion mechanism,and the importance of the struc-ture factor was *** exposure tests were conducted to verify the calculated results using the GBDT *** indic-ated that the GBDT method can be effectively used to study the influence of structural factors on the corrosion process of 3Ni ***-ferent mechanisms for the addition of Mn and Cu to the stress-assisted corrosion of 3Ni steel suggested that Mn and Cu have no obvious effect on the corrosion rate of non-stressed 3Ni steel during the early stage of *** the corrosion reached a stable state,the in-crease in Mn element content increased the corrosion rate of 3Ni steel,while Cu reduced this *** the presence of stress,the increase in Mn element content and Cu addition can inhibit the corrosion *** corrosion law of outdoor-exposed 3Ni steel is consistent with the law based on corrosion big data technology,verifying the reliability of the big data evaluation method and data prediction model selection.

关键词： weathering steel stress-assisted corrosion gradient boosting decision tree machining learning

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Active flutter suppression of nonlinear fin-actuator system via inverse system and immersion and invariance method

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Chinese Journal of Aeronautics 2024年第4期37卷 343-362页

作者： Jin LU Zhigang WU Chao YANG Chinese aeronautical Establishment Beijing 100029China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China

Structural nonlinearities such as freeplay will affect the stability and even flight safety of the fin-actuator *** is a lack of a practical method for designing Active Flutter Suppression (AFS) control laws for nonlinear fin-actuator systems.A design method for the AFS controller of the nonlinear all-movable fin-electromechanical actuator system is established by combining the inverse system and the Immersion and Invariance (I&I) ***,the composite control law combining the inverse system principle and internal model control is used to offset the nonlinearity and dynamics of the actuator,so that its driving torque can follow the ideal ***,the ideal torque of the actuator is designed employing the I&I *** unfavorable oscillation of the fin is suppressed by making the output torque of the actuator track the ideal *** simulation results reveal that the proposed AFS method can increase the flutter speed of the nonlinear finactuator system with freeplay,and a set of controller parameters is also applicable for wider freeplay within a certain *** power required for the actuator does not exceed the power that can be provided by the commonly used aviation *** method can also resist a certain level of noise and external disturbance.

关键词： Aeroelasticity Active flutter suppression Fin-actuator system Freeplay Inverse system Immersion and invariance

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Unmanned autonomous air-to-air refueling intelligent docking technology

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Chinese Journal of Aeronautics 2024年第5期37卷 1-5页

作者： Peng LIN Yakun HE Yuanze CHEN Chinese aeronautical Establishment Beijing 100029China

Unmanned autonomous Air-to-Air Refueling(AAR)capability is the key guarantee to support the distant-field,high-intensity and durable operations of the penetration counterair combat *** the future,the long-range unmanned reconnaissance and attack platform can reach the maximum flight range requirement through *** present,large transport aircraft platforms in China are still equipped with probe-and-drogue systems,and the refueling mode is gradually changing from manned to unmanned autonomous *** docking process is the riskiest and most important part,and there are strict safety,precision,and efficiency requirements for refueling operation,especially during close-distance docking and formation maintenance *** this paper,five issues that need to be solved to achieve autonomous AAR docking are *** this basis,five key technology development needs are proposed to solve these engineering ***,some prospects are given.

关键词： Air-to-air refueling Probe-and-drogue Unmanned aerial vehicles Docking Perception Collaborative control

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A self-organization formation configuration based assignment probability and collision detection

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Journal of Systems Engineering and Electronics 2024年第1期35卷 222-232页

作者： SONG Wei WANG Tong YANG Guangxin ZHANG Peng School of Harbin Engineering University Harbin 150001China Chinese aeronautical Establishment Beijing 100010China

The formation control of multiple unmanned aerial vehicles(multi-UAVs)has always been a research *** on the straight line trajectory,a multi-UAVs target point assignment algorithm based on the assignment probability is proposed to achieve the shortest overall formation path of multi-UAVs with low complexity and reduce the energy *** order to avoid the collision between UAVs in the formation process,the concept of safety ball is introduced,and the collision detection based on continuous motion of two time slots and the lane occupation detection after motion is proposed to avoid collision between *** on the idea of game theory,a method of UAV motion form setting based on the maximization of interests is proposed,including the maximization of self-interest and the maximization of formation interest is proposed,so that multi-UAVs can complete the formation task quickly and reasonably with the linear trajectory assigned in ***,through simulation verification,the multi-UAVs target assignment algorithm based on the assignment probability proposed in this paper can effectively reduce the total path length,and the UAV motion selection method based on the maximization interests can effectively complete the task formation.

关键词： straight line trajectory assignment probability collision detection lane occupation detection maximization of interests

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Design and validation of a variable camber wing structure

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Chinese Journal of Aeronautics 2024年第2期37卷 1-11页

作者： Xiasheng SUN Jingfeng XUE Jin ZHOU Zhigang WANG Wenjuan WANG Mengjie ZHANG Chinese aeronautical Establishment Beijing 100012China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China Aircraft Strength Research institute of China Xi’an 710065China Graduate School of Chinese aeronautical Establishment Yangzhou 225002China

Variable camber wing technology is one of the important development trends of green aviation at *** smooth,seamless,continuous and adaptive change of wing camber,the aerodynamic performance is improved in achieving increase in lift and reduction in resistance and *** on the aerodynamic validation model CAE-AVM,Chinese aeronautical Establishment(CAE)has carried out the design and validation of a variable camber wing,proposed an aerodynamic deformation matrix for the leading and trailing edges of aircraft wings in takeoff,landing and cruise *** structures and driving schemes are compared,and several key technology problems of leading and trailing edge deformation are solved.A full-size leading edge wind tunnel test piece with a span of 2.7 m and a trailing edge ground function test piece are *** deformation and shape maintenance capabilities of the leading edge is verified under real wind load conditions,and the load bearing and deformation capabilities of the trailing edge is verified under simulated follow-on *** results indicate that the leading and trailing edges of the variable camber wing can achieve the required deformation angle and have a certain load-bearing *** study can provide some insights into the application of variable camber wing technology for civil aircraft.

关键词： Variable camber wing Leading edge Trailing edge Structure Measurement and control Test

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Single image defogging via multi-exposure image fusion and detail enhancement

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Journal of Safety Science and Resilience 2024年第1期5卷 37-46页

作者： Wenjing Mao Dezhi Zheng Minze Chen Juqiang Chen School of Information and Electronics Advanced Research Institute of Multidisciplinary ScienceBeijing Institute of TechnologyBeijing100081China Chinese aeronautical Establishment Beijing100012China

Outdoor cameras play an important role in monitoring security and social *** a common weather phenomenon,haze can easily affect the quality of camera shooting,resulting in loss and distortion of image *** paper proposes an improved multi-exposure image fusion defogging technique based on the artificial multi-exposure image fusion(AMEF)***,the foggy image is adaptively exposed,and the fused image is subsequently obtained via multiple *** fusion weight is determined by the saturation,contrast,and ***,the image fused by a multi-scale Laplacian algorithm is enhanced with simple adaptive details to obtain a clearer defogging *** is subjectively and objectively verified that this algorithm can obtain more image details and distinct picture colors without a priori information,effectively improving the defogging ability.

关键词： Image defogging Multi-scale fusion Laplacian pyramid Adaptive detail enhancement

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Effect of trace oxygen on plasma nitriding of titanium foil

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Chinese Physics B 2024年第6期33卷 548-551页

作者：周海涛熊希雅马可欣罗炳威罗飞申承民 beijing institute of aeronautical Materials Aero Engine Corporation of ChinaBeijing 100095China beijing National Laboratory of Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

Titanium nitride films are prepared by plasma enhanced chemical vapor deposition method on titanium foil using N_(2) as precursor. In order to evaluate the effect of oxygen on the growth of titanium nitride films, a small amount of O_(2) is introduced into the preparation process. The study indicates that trace O_(2) addition into the reaction chamber gives rise to significant changes on the color and micro-morphology of the foil, featuring dense and long nano-wires. The as-synthesized nanostructures are characterized by various methods and identified as TiN, Ti_(2) N, and TiO_(2) respectively. Moreover, the experiment results show that oxide nanowire has a high degree of crystallinity and the nitrides present specific orientation relationships with the titanium matrix.

关键词： nitride oxide nanostructure crystalline plasma-enhanced chemical vapor deposition system(PECVD)

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Microstructure evolution and phase transformation of the mushy zone in a quenchedβ-solidifying TiAl alloy

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Journal of Materials Science & Technology 2024年第2期169卷 28-41页

作者： Fuqiang Zhang Xianfei Ding Leming Xu Xin Feng Hai Nan Jianping He Yongfeng Liang Junpin Lin State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Cast Titanium Alloy R&D Center Beijing Institute of Aeronautical MaterialsBeijing 100095China

This study investigates the phase constitutions and transformations that occur in the mushy zone and in the adjacent phase fields of a directionally solidified Ti-44Al-8Nb-1Cr alloy via quenching *** results indicate that the mushy zone consists of unmeltedβdendrites and interdendritic liquid,whose formation can be attributed to the difference in melting point aroused by local heterogeneity in ***βdendrite is composed of numerous subgrains with various *** quenching,theβdendrite transforms into Widmanstättenαvia a precipitation reaction,owing to the decreasing cooling rate caused by heat transfer from the surrounding ***,after quenching,the interdendritic liquid is transformed intoγ*** the singleβphase field and the lower part of the mushy zone,a massive transformation ofβtoγ***,in theβ+αphase field,bothβandαphases are retained to ambient *** the heating process,the transformation ofα→βgives rise to the formation ofβvariants,which affects the orientation ofβdendrites in the mushy *** growth kinematics of theα→βtransformation was elucidated,revealing the preferential growth directions of111and112forβ***,this study presents an illustration of the formation process of the mushy zone and the microstructural evolution during the heating and quenching process.

关键词： Titanium aluminides Mushy zone Quenching Electron backscattering diffraction Phase transformation

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Creep property and microstructural evolution of DD11 alloy under high temperature and low stress

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Rare Metals 2024年第2期43卷 810-816页

作者： Yan-Fei Liu Jiang-Bo Sha Yun-Song Zhao Chen-Guang Liu Yuan-Yuan Guo Jian Zhang Yu-Shi Luo School of Materials Science and Engineering Beihang UniversityBeijing100191China Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical MaterialsBeijing100095China

In this paper,the interrupted and ruptured creep tests were carried out in a novel second generation single crystal superalloy named DD11 at 1100℃/130 *** alloy exhibited typical creep curve including primary,steady,and tertiary three creep *** microstructural evolution at different stages of the creep were analyzed by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The results show that theγ′phases transform into rafted structure at the early stage of the steady creep and keep stable during the steady creep *** the creep goes on,the rafted structure further coarsens and the topological inversion *** addition,at the primary creep,the dislocations mainly move in theγmatrix and pile up in theγ/γ′interface since the matrix channels widen *** formation of the regular interfacial dislocation networks occurs at the early stage of the steady *** the low stress,the dominated deformation mechanism during steady creep stage is the climbing of the〈010〉type edge ***,the effect of the deformation mechanism on creep property was discussed in detail.

关键词： DD11 alloy Creep property Interrupted creep test Rafted structure Deformation mechanism

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Tube-based robust reinforcement learning for autonomous maneuver decision for UCAVs

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Chinese Journal of Aeronautics 2024年第7期37卷 391-405页

作者： Lixin WANG Sizhuang ZHENG Haiyin PIAO Changqian LU Ting YUE Hailiang LIU School of aeronautical Science and Engineering Beihang UniversityBeijing 100191China Shenyang Aircraft Design&Research institute Shenyang 110035China

Reinforcement Learning(RL)algorithms enhance intelligence of air combat AutonomousManeuver Decision(AMD)policy,but they may underperform in target combat environmentswith *** enhance the robustness of the AMD strategy learned by RL,thisstudy proposes a Tube-based Robust RL(TRRL)***,this study introduces a tube todescribe reachable trajectories under disturbances,formulates a method for calculating tubes basedon sum-of-squares programming,and proposes the TRRL algorithm that enhances robustness byutilizing tube size as a quantitative ***,this study introduces offline techniques forregressing the tube size function and establishing a tube library before policy learning,aiming toeliminate complex online tube solving and reduce the computational burden during ***,an analysis of the tube library demonstrates that the mitigated AMD strategy achievesgreater robustness,as smaller tube sizes correspond to more cautious *** finding highlightsthat TRRL enhances robustness by promoting a conservative *** effectively balanceaggressiveness and robustness,the proposed TRRL algorithm introduces a“laziness factor”as aweight of ***,combat simulations in an environment with disturbances confirm thatthe AMD policy learned by the TRRL algorithm exhibits superior air combat performance comparedto selected robust RL baselines.

关键词： Air combat Autonomous maneuver decision Robust reinforcement learning Tube-based algorithm Combat simulation

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