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High-entropy(Sm_(0.2)Eu_(0.2)Gd_(0.2)Dy_(0.2)Er_(0.2))_(2)Hf_(2)O_(7) ceramic with superb resistance to radiation-induced amorphization

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Journal of Materials science & technology 2023年第24期155卷 1-9页

作者： Jingxin Wu Meng Zhang Zhanqiang Li Minzhong Huang Huiming Xiang Liyan Xue Zhengming Jiang Zhigang Zhao Lianfeng Wei Yong Zheng Fan Yang Guang Ran Yanchun Zhou Heng Chen School of Rare Earths University of Science and Technology of China Hefei 230026 China Ganjiang Innovation Academy Chinese Academy of Sciences Ganzhou 341000 China Xiamen Institute of Rare Earth Materials Haixi Institute Chinese Academy of Sciences Xiamen 361021 China Fujian Province Joint Innovation Key Laboratory of Fuel and Materials in Clean Nuclear Energy System Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences Fuzhou 350002 China Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108 China Science and Technology on Advanced Functional Composite Laboratory Aerospace Research Institute of Materials & Processing Technology Beijing 100076 China The Key Nuclear Fuel and Nuclear Materials Laboratory of China Nuclear Power Institute of China Chengdu 610213 China China Rare Earth Group Co. Ltd. Chengdu 610213 China College of Energy Xiamen University Xiamen 361102 China School of Materials Science and Engineering Zhengzhou University Zhengzhou 450001 China

Nuclear engineering materials are required to possess outstanding extreme environmental tolerance and irradiation resistance.A promising novel pyrochlore-type of(Sm_(0.2)Eu_(0.2)Gd_(0.2)Dy_(0.2)Er_(0.2))2 Hf_(2)O_(7)high-entropy ceramic(HE-RE2 Hf_(2)O_(7))for control rod was prepared by solid-state reaction *** ion irradiation of HE-RE_(2) Hf_(2)O_(7)with 400 keV Kr+at 400℃was investigated using a 400 kV ion implanter and compared with single-component pyrochlore Gd2 Hf_(2)O_(7)to evaluate the irradiation *** HE-RE2 Hf_(2)O_(7),the phase transition from pyrochlore to defective fluorite is revealed after irradiation at 60 *** irradiation at 120 dpa,it maintained crystalline,which is comparable to Gd2 Hf_(2)O_(7)but superior to the titanate pyrochlores previously ***,the lattice expansion of HE-RE2 Hf_(2)O_(7)(_(0.2)2%)is much lower than that of Gd2 Hf_(2)O_(7)(0.62%),indicating excellent irradiation damage *** tests displayed an irradiation-induced increase in hardness and a decrease in elastic modulus by about 2.6%.Irradiation-induced segregation of elements is observed on the surface of irradiated *** addition,HE-RE2 Hf_(2)O_(7)demonstrates a more sluggish grain growth rate than Gd2 Hf_(2)O_(7)at 1200℃,suggesting better high-temperature *** linear thermal expansion coefficient of HE-RE2 Hf_(2)O_(7)is 10.7×10-6 K-1 at 298–1273 *** general,it provides a new strategy for the design of the next advanced nuclear engineering materials.

关键词： High-entropy ceramic Rare earth hafnate Ion irradiation Amorphization resistance High temperature stability Nuclear safety

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Study on the thinning characteristics of aviation tubes during bending forming under boundary lubrication friction

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Journal of Manufacturing Processes 2025年 149卷 443-455页

作者： Yu Wu Zhineng Wang Jing Tian Renzhen Chen Weiming Lin Yaochen Lin Health Maintenance for Mechanical Equipment Key Lab Hunan University of Science and Technology Xiangtan 411201 China Liaoning Key Laboratory of Advanced Measurement and Test Technology for Aviation Propulsion System Shenyang Aerospace University Shenyang 110136 China Zhejiang King-Mazon Intelligent Manufacturing Corp. Ltd Lijiang 321400 China

The reduction of wall thickness during the bending forming process of aviation tubes is a common issue, particularly for large-diameter, thick-walled tubes. Under heavy load conditions, the lubrication state deteriorates, leading to a boundary lubrication state that complicates the prediction of wall thickness reduction. Current research on tube bending forming relies on Coulomb friction, which does not accurately reflect real-world conditions. Therefore, we propose a method for analysing tube thinning during bending forming that considers the friction characteristics of boundary lubrication. ABAQUS/VFRIC was employed to develop a dynamic friction model that considers contact pressure. Additionally, material hardness and RMS roughness were incorporated into the finite element simulation. Results show that as the tubing advances, the contact area between the pressure die and the tube changes and the friction between them generates a certain amount of compressive stress. An increase in contact pressure results in a higher friction coefficient, leading to a substantial rise in the tensile stress on the tube's exterior, further aggravating the thinning of the outer wall. In particular, stress concentrations and elevated strains resulting from boundary lubrication friction are especially pronounced at the 40° and 60° bending positions. In addition, increased RMS roughness and decreased material hardness contribute to more significant thinning effects. Experimental verification indicates that this dynamic friction model offers greater accuracy than the traditional Coulomb friction model in predicting wall thickness thinning, achieving a maximum error reduction to 3% and an accuracy enhancement of 7%. The findings provide theoretical support for process optimisation in aerospace manufacturing and establish a foundation for designing and implementing high-precision forming processes.

关键词： Bending forming Friction model Wall thinning

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Short-term multi-step-ahead sector-based traffic flow prediction based on the attention-enhanced graph convolutional LSTM network (AGC-LSTM)

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Neural Computing and Applications 2024年 1-20页

作者： Zhang, Ying Xu, Shimin Zhang, Linghui Jiang, Weiwei Alam, Sameer Xue, Dabin College of General Aviation and Flight Nanjing University of Aeronautics and Astronautics Nanjing China State Key Laboratory of Air Traffic Management System Nanjing China College of Computer Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing China School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing China Air Traffic Management Research Institute School of Mechanical & ampAerospace Engineering Nanyang Technological University Singapore Singapore Department of Land Surveying and Geo-Informatics The Hong Kong Polytechnic University Hong Kong

Accurate sector-based air traffic flow predictions are essential for ensuring the safety and efficiency of the air traffic management (ATM) system. However, due to the inherent spatial and temporal dependencies of air traffic flow, it is still a challenging problem. To solve this problem, some methods are proposed considering the relationship between sectors, while the complicated spatiotemporal dynamics and interdependencies between traffic flow of route segments related to the sector are not taken into account. To address this challenge, the attention-enhanced graph convolutional long short-term memory network (AGC-LSTM) model is applied to improve the short-term sector-based traffic flow prediction, in which spatial structures of route segments related to the sector are considered for the first time. Specifically, the graph convolutional networks (GCN)-LSTM network model was employed to capture spatiotemporal dependencies of the flight data, and the attention mechanism is designed to concentrate on the informative features from key nodes at each layer of the AGC-LSTM model. The proposed model is evaluated through a case study of the typical enroute sector in the central–southern region of China. The prediction results show that MAE reduces by 14.4% compared to the best performing GCN-LSTM model among the other five models. Furthermore, the study involves comparative analyses to assess the influence of route segment range, input and output sequence lengths, and time granularities on prediction performance. This study helps air traffic managers predict flight situations more accurately and avoid implementing overly conservative or excessively aggressive flow management measures for the sectors. © The Author(s) 2024.

关键词： Forecasting

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Method and technology of in-situ ultrafast laser micro-forging assisted laser powder bed fusion for high-performance additive manufacturing

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Scientia Sinica Technologica 2025年第5期55卷 827-835页

作者： Zhou, LiuCheng Li, YingHong National Key Laboratory of Aerospace Power System and Plasma Technology Aviation Engineering School Air Force Engineering University Xi’an710038 China

Additive manufacturing (AM) technology enables the integral formation of complex-shaped structures and lightweight topological designs, providing an important technical approach to promote the development of equipment and manufacturing industries. However, AM components manufactured by laser powder bed fusion (LPBF) currently face some significant challenges, such as large thermal stress, defects, and insufficient fatigue performance. These issues restrict their use in clinical load-bearing and moving parts, representing a globally recognized technical challenge and industry pain point. To address these limitations, our group has developed an innovative method that combines ultrafast laser shock peening and LPBF, referred to as in-situ ultrafast laser micro-forging assisted LPBF. This method uses ultrafast laser-induced shock waves to peen the molten layer in-situ, allowing for layer-by-layer control of stress, microstructure, and defect distribution. This approach significantly enhances the mechanical properties of AM parts, supports unsupported structures, achieves high surface finish AM, and enables the forming of hard-to-form metal materials. This paper introduces the connotation and characteristics of this technology, evaluates its advantages and effectiveness based on preliminary test data from titanium alloys, superalloys, aluminum alloys, and other metal materials, and highlights the fundamental problems that require further research. © 2025 science Press. All rights reserved.

关键词： Aluminum alloys

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Study on the Impact of Novel Flow Channel Structures With Spherical Obstacles on SOFC Performance

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Kung Cheng Je Wu Li Hsueh Pao/Journal of Engineering Thermophysics 2025年第4期46卷 1343-1346页

作者： Zhao, Weiwei He, Zhenzong Mao, Junkui Liang, Fengli Wang, Zaixing Fu, Yao Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering Nanjing210016 China Collaborative Innovation Center for Advanced Aero-Engine Beijing100191 China Aviation Key Laboratory of Science and Technology on Aero Electromechanical System Integration Nanjing211106 China

To enhance the performance of Solid Oxide Fuel Cells (SOFCs), a new flow channel with spherical obstacles is proposed and compared with traditional designs. It is concluded that compared with the basic straight channel, the current density of SOFC with rectangular baffles and SOFC with spherical obstacles increases by 6.42% and 7.14%, and the total pressure drop increases by 3.62 times and 2.16 times, respectively. It is thus evident that the new SOFC design proposed in this paper can be used for better overall performance. © 2025 science Press. All rights reserved.

关键词： Numerical models

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AEROACOUSTIC INVESTIGATION OF GRID TURBULENCE INTERACTING WITH ROTORS 29

AEROACOUSTIC INVESTIGATION OF GRID TURBULENCE INTERACTING WI...

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29th International Congress on Sound and Vibration, ICSV 2023

作者： Wu, Han Chen, Wangqiao Zhang, Xin Zhong, Siyang Huang, Xun Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong Department of Aeronautical and Aviation Engineering The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong State Key Laboratory for Turbulence and Complex System Department of Aeronautics and Astronautics College of Engineering Peking University Beijing China

ISBN: (纸本)9788011034238

The aerodynamic noise of rotors is an environmental constraint in the operation of multi-rotor powered urban air mobility (UAM) vehicles. It is essential to study the rotor noise in turbulent flows that are common in practical flights. In this work, a benchmarking turbulence grid is installed in the jet exit of an open-jet anechoic wind tunnel to generate turbulent flows. The grid-generated turbulence is characterized by the hot-wire anemometry at several downstream locations of the grid. The hot-wire results show that the turbulence intensity decays with the streamwise locations, following a power law of -5/7. The power spectral properties of the grid turbulence are also assessed, indicating a good agreement with the von Kármán turbulence spectrum. Then, the aerodynamic force and noise of a high-speed rotating rotor with a diameter of 217 mm are measured in both clean and turbulent flows. Force measurements show that the thrust and torque coefficients decrease with the advance ratio J, and the coefficient curves collapse well for all the rotational speeds. The rotor induces more torque and power under the grid turbulence. The noise measurements show that the broadband noise above 1,000 Hz can be significantly increased by turbulence, and a difference of more than 10 dB can be observed at J = 0.84. The noise directivity indicates that turbulence interaction noise is more significant at the rotor upstream. The turbulence interaction noise of rotors can impose a significant noise source to surroundings, the physics of which needs to be further investigated for noise reductions of future UAM vehicles. © 2023 Proceedings of the International Congress on Sound and Vibration. All rights reserved.

关键词： Turbulence

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A Method for Reconstructing the Shape of Wing Panels Based on Fiber Optic Sensors and Tomographic Imaging Principles

A Method for Reconstructing the Shape of Wing Panels Based o...

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Prognostics and system Health Management Conference (PHM-Qingdao)

作者： Jun Zhan Jie Zeng Chao Xiang Jinpeng Cui Cheng Zeng Linfeng Zhu Mingyu Lu State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and Astronautics Nanjing China Aviation key laboratory of science and technology on aero electromechanical system integration Nanjing engineering institute of aircraft system jincheng AVIC Nanjing China Changping District Xiaotangshan Future Science and Technology City COMAC Beijing Aircraft Technology Research Institute Beijing China

ISBN: (数字)9798350354010

ISBN: (纸本)9798350354027

The aircraft wing structure shape reconstruction method based on discrete strain information not only provides data support for the digital collaborative health monitoring and prediction technology of wing structure but also helps to improve the aerodynamic shape and flight quality of the aircraft, achieve structural stealth, and enhance the pointing accuracy of the on-board conformal antenna. As result, a wing skin panel shape reconstruction method based on the principle of tomographic imaging and strain information perception is proposed. According to the idea of tomographic imaging, a “non-intrusive” layout form that only requires sensors to be arranged on the periphery of the monitoring area is designed, breaking through the limitation that sensors can not be arranged in the monitoring area under special working conditions. A method for constructing the deflection shape function of the wing skin panel based on the concept of synthetic curvature is proposed, solving the problem of error accumulation and elimination of deformation inversion at non-monitoring points of the measured structure caused by the uncertainty of the limited discrete layout of sensors and the choice of interpolation fitting method. On this basis, a model deformation monitoring and inversion system for wing skin panel based on fiber optic grating sensors is constructed. The experimental results show that under the single-end fixed bending and torsion working condition, the average relative error of the panel model shape reconstruction is 4.17%. Under the double-end fixed double-concentrated load working condition, the average relative error of the shape reconstruction is 8.07%. The wing deformation distribution information reconstructed by the method proposed in this paper can be mapped onto the virtual twin model of the wing, providing technical support for the safety assessment, early warning, and on-condition maintenance of the entire service life of key structures of the aircraft.

关键词： Employee welfare Shape Deformation Layout Imaging Sensors Aircraft Monitoring Image reconstruction Strain

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Simulation Study on the Influence of Rocket Tail Flame of Ejection Seat on the Thermal Flow Field in Engine Room 5th

Simulation Study on the Influence of Rocket Tail Flame of Ej...

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5th China aviation science and technology Conference, 2021

作者： Jin, Lou Wu, Yibin Wu, Liang Cui, Dongyue Yang, Pin Overall Technology R&D Department AVIC Aerospace Life-Support Industries Ltd Xianyang441000 China Aviation Key Laboratory of Science and Technology On Life-Support Technology Xianyang441000 China Institute of Mechanical and Electrical System AVIC The First Aircraft Institute Xi’an710000 China

ISBN: (纸本)9789811674228

This paper proposes a simulation method and technology for the effect of the ejection seat rocket pack tail flame on the heat flow field of the engine room under the multi-seat ejection condition, combines the six-degree-of-freedom motion model of the ejection seat with the CFD numerical simulation method to realize the simulation process of the thermal flow field in the engine room according to the working mechanism of the seat. The motion trajectory and attitude change law of the first ejected seat under different ejection conditions is calculated by a program written in C#, the movement of the human-seat system and the rocket at the boundary in FLUENT is specified with UDF, then the temperature and pressure change law of the second ejected seat, occupant and the surface of the cockpit during a side ejection at different ejection speeds are simulated. The simulation results show that the temperature of different characteristic points in the engine room rises first and then decreases after the rocket package is working, reaching a peak at about 60ms. The temperature at the back of the seat is the highest, and the temperature in the engine room drops faster while the pressure peak is lower when the seat is ejected at a certain speed. The analysis results can provide a theoretical basis for the design and verification of occupant thermal protection equipment. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Computational fluid dynamics

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Predicting Vibration Fatigue Strength and Three-Dimensional Fatigue Crack Growth in Simulated Compressor Blade by Phase-Field Model

SSRN

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SSRN 2024年

作者： Sun, Shen Liu, Shijie He, Weiwei Zhang, Xuan Tang, Wei Zhou, Liucheng Yi, Min Nanjing210016 China Beijing Aerospace Propulsion Institute Laboratory of Science and Technology on Cryogenic Liquid Propulsion Beijing100076 China National Key Lab of Aerospace Power System and Plasma Technology Air Force Engineering University Xi’an710038 China

Vibration fatigue is a major concern for aeroengine compressor blades under complex cyclic mechanical and aero-dynamic loads, but predicting vibration fatigue behavior of blades remains challenging. Herein, a phase-field fatigue fracture model is applied to simulate the vibration fatigue behavior of the simulated compressor blade. In the phase-field model, a logarithmic degradation function is adopted to describe the fracture toughness decreasing with fatigue cycles. Vibration induced cyclic loads are mimicked by the pressure applied on the blade surface. The three-dimensional (3D) fatigue crack propagation of the simulated blade is simulated. It is found that the fatigue crack initiates at the variable cross-section and propagates horizontally. Laser shock peening (LSP) is further shown to improve the fatigue properties, i.e., LSP induced compressive residual stress results in a 95% increase of fatigue life and notably retards the 3D fatigue crack growth. For the vibration fatigue strength of both the original and LSPed blades, the predictions are within the ±5% error band. The phase-field model here provides a predictive approach for the evaluation of vibration fatigue behavior and shows a great potential in the optimal design of durable and reliable compressor blades. © 2024, The Authors. All rights reserved.

关键词： Fatigue crack propagation

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Tesla Rdc Operation and Performance

SSRN

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SSRN 2024年

作者： Song, Feilong Wu, Yun Yang, Xingkui Zhou, Jianping Xu, Shida Kang, Jinhui Wang, Jiaojiao National Key Lab of Aerospace Power System and Plasma Technology Air Force Engineering University Xi’an710038 China Institute of Aeroengine Xi’an Jiaotong University Xi’an710049 China Beijing Aeronautical Technology Research Center Beijing100071 China Key Laboratory of Complex Aviation Simulation System Beijing100076 China

The suppression of pressure feedback and the control for detonation wave operating mode play a key role in improving the stagnation pressure gain of RDC. In this study, a unique Tesla RDC, in which Tesla pneumatic valve is introduced into the inlet structure and combustion chamber, has been tested compared with traditional configuration (RP-3 kerosene as fuel) at a flow rate of 1kg/s under the outlet throat to air inlet area ratio of 3. It is observed that the application of Tesla valve effectively controls the propagation direction of detonation wave and rotates clockwise as expected. At the same time, the percentage of pressure fluctuation to the static pressure in plenum decreases as a whole, and the lowest is only 4.2%. The maximum pressure gain obtained by equivalent available pressure method in all operating conditions is -26.1%. In addition, there is a linear relationship between thrust and air plenum pressure (Pt2), and when the Pt2 increases, the percentage of thrust to the required for the theoretical pressure gain of 0 increases gradually, up to 60.8% at the equivalence ratio of 0.65 and Pt2 of 2.47atm. It is predicted that a higher stagnation pressure gain will be achieved by carrying out a larger flow rate of 2.5kg/s and increasing Pt2 to 6.1atm. This work provides a new idea for RDC feedback suppression and mode control, and demonstrates the potential advantages of Tesla valve in RDC. © 2024, The Authors. All rights reserved.

关键词： Detonation

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