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2024 CSAA/IET International Conference on Aircraft Utility Systems, AUS 2024

作者： Renlei, Wei Shuai, Wu Bing, Chu Yuliang, Yang Jianing, Luo School of Automation Science and Electrical Engineering Beihang University Beijing100191 China National Key Laboratory of Aircraft Integrated Flight Control Beihang University Beijing100191 China Key Laboratory of Advanced Aircraft Systems Beihang University Ministry of Industry and Information Technology Beijing100191 China Ningbo Institute of Technology Beihang University Ningbo315800 China Tianmushan Laboratory Hangzhou310023 China AVIC Shenyang Aircraft Design and Research Institute Shenyang110035 China

The electro-hydrostatic actuator (EHA) has the advantage of high power weight ratio, less leakage and the absence of throttle loss. It's used on the multi-electric aircraft and the all-electric aircraft. However, it will be affected by the aerodynamic load and the rudder flutter will occur if the dynamic stiffness of the EHA is low. As a result, it's significant to analyse the sensitivity of the EHA's parameters on the dynamic stiffness. The article builds a linear model of the EHA considering the leakage in the system. What's more, the local parameter sensitivity for the dynamic stiffness is calculated when the frequency is between 0.01 Hz and 1000 Hz. © The Institution of Engineering & technology 2024.

关键词： Sensitivity analysis

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Dynamic oxidation mechanism of carbon fiber reinforced SiC matrix composite in high-enthalpy and high-speed plasmas

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Journal of Advanced Ceramics 2022年第2期11卷 365-377页

作者： Lingwei YANG Xueren XIAO Liping LIU Jie LUO Kai JIANG Xinxing HAN Changhao ZHAO Jun ZHANG Guolin WANG Hypervelocity Aerodynamics Institute China Aerodynamics Research and Development CenterMianyang 621000China Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical UniversityXi’an 710072China Shandong Research and Design Institute of Industrial Ceramics Co.Ltd.Zibo 255000China

This work employed an inductively coupled plasma wind tunnel to study the dynamic oxidation mechanisms of carbon fiber reinforced SiC matrix composite(C_(f)/SiC)in high-enthalpy and high-speed *** results highlighted a transition of passive/active oxidations of SiC at 800–1600℃and 1–5 ***,the active oxidation led to the corrosion of the SiC coating and interruption of the SiO_(2) *** transition borders of active/passive oxidations were thus defined with respect to oxidation temperature and partial pressure of atomic O in the high-enthalpy and high-speed *** the transition and passive domains,the SiC dissipation was *** multiple dynamic oxidations of C_(f)/SiC in the domains,the SiO_(2) thickness was not monotonously increased due to the competing mechanisms of passive oxidation of SiC and dissipation of SiO_(2).In addition,the mechanical properties of the SiC coating/matrix and the C_(f)/SiC were maintained after long-term dynamic oxidations,which suggested an excellent thermal stability of C_(f)/SiC serving in thermal protection systems(TPSs)of reusable hypersonic vehicles.

关键词： thermal protection system(TPS) ceramic matrix composite oxidation mechanism plasma wind tunnel mechanical property

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Experimental Study of Coherent Structures Downstream Mixing Vaned Spacer Grid of Different Inclination Angles in a 5×5 Rod Bundle by Tr-Piv

SSRN

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SSRN 2022年

作者： Qu, Wenhai Xie, Hao Shen, Danhong Wang, Zefeng Xiong, Jinbiao School of Nuclear Science and Engineering Shanghai Jiao Tong University Shanghai China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

Experimental study of coherent structures downstream of a spacer grid with different inclination angles of mixing vanes in a 5×5 rod bundle was conducted by TR-PIV under four Reynolds *** coherent structures downstream of spacer grid change with several patterns. The developments of lateral time-averaged velocity, Reynolds stress, dominant frequency, integral spatial length scales and integral temporal length scales are determined by coherent structures. Smaller coherent structures are generated with Reynolds number increasing, and time-averaged velocity, Reynolds stress, St numbers, spatial and temporal length scales decrease. Larger inclination angle generates larger coherent structures, and spatial and temporal length scales increase with inclination angle increasing. The coherent structures indicate strong anisotropy of turbulent flow in rod *** experimental findings provide valuable information for understanding sub-channel mixing phenomena caused by mixing vaned spacer grids. The experimental data can be used for sub-channel mixing model developments and validations of turbulent models. © 2022, The Authors. All rights reserved.

关键词： Reynolds number

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Experimental Study of Coherent Structures Downstream Mixing Vaned Spacer Grid of Different Inclination Angles in a 5×5 Rod Bundle by Tr-Piv

SSRN

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SSRN 2022年

关键词： Reynolds number

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Simulation Analysis of the Effect of Sensor Disturbances on Transient Electromagnetic Field Calibration 5

Simulation Analysis of the Effect of Sensor Disturbances on ...

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5th IEEE International Conference on Electronic Information and Communication technology, ICEICT 2022

作者： Yang, Yuanpeng Huang, Songgao Shi, Xinyang Fang, Chonghua Science and Technology on Electromagnetic Compatibility Laboratory China Ship Development and Design Centre Wuhan China Wuhan Maritime Communication Research Institute Wuhan China

ISBN: (数字)9781665472111

ISBN: (纸本)9781665472111

In the measurement of the time domain waveform of TEM electromagnetic waves, the B-DOT magnetic field probe and the D-DOT electric field probe are often used to measure the electromagnetic field time domain waveform in space. When using simulation software to simulate electromagnetic field problems, the electromagnetic fields in the simulation model are often measured using the ideal probe. The ideal probe in the simulation software is different from the probe actually used, and in actual use, the size, shape and material of the probe often have a certain impact on the electromagnetic field and cannot be ignored. Therefore, using an ideal probe in simulation may deviate from the time-domain waveform actually measured with the probe in the experiment. © 2022 IEEE.

关键词： Probes

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Characteristic Parameters Analysis of Bond-Wire Failure for Multi-Chips Parallel IGBT Modules

Characteristic Parameters Analysis of Bond-Wire Failure for ...

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IEEE/IAS Industrial and Commercial Power System Asia (I&CPS Asia)

作者： Yuan Min Zhen Xing Xueni Ding Hui Li Ran Yao Wei Lai Cheng Yang Wenxing Han Yannan Yuan Key Laboratory of Nuclear Reactor System Design Technology ChengDu China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China Chongqing University Chongqing China

Multi-chips parallel IGBT module is widely used in new energy power grid connection, flexible AC and DC transmission, electric vehicles and charging devices, rail transit electric traction and other fields, and the reliability of their operation is very important. Therefore, how to select the characteristic parameters that can characterize the aging state of multi-chips parallel IGBT device is particularly important for system active operation and maintenance and reliability improvement. This paper takes the widely used multi-chips parallel IGBT module as the research object. According to the failure mode of bond wire lift-off, the degradation law of electrothermal and magnetic characteristic parameters in the aging failure process of the multi-chips parallel IGBT module was studied, and finally the magnetic flux density was selected as the aging state monitoring parameter of the multi-chips parallel IGBT module.

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Microstructure Characterization and Failure Mechanism of Laser Welded Nuclear-grade FeCrAl Alloy 10

Microstructure Characterization and Failure Mechanism of Las...

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2023 10th International Conference on Advanced Manufacturing technology and Materials Engineering, AMTME 2023

作者： Zhan, Yaqi Niu, Yitian Hu, Yanying Zhang, Ruiqian Ma, Xianfeng Liu, Jinping Feng, Yingchao Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen University Guangdong Zhuhai519082 China Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of China Chengdu Sichuan610041 China Key Laboratory for Highly Efficient and Intelligent Welding of China National Nuclear Corporation China Nuclear Industry 23 Construction Co. Ltd Beijing101300 China

FeCrAl alloy is considered a new type of promising accident-tolerant fuel cladding material. Laser welding technology, which has been widely applied in the connection of various metal materials, uses a high energy density laser heat source with the advantages of efficiency and precision. However, due to the inherent characteristic of high speed, the laser weld is generally exposed to rapid solidification, resulting in the inevitable formation of defects such as coarse grain size and porosity in the weld. The presence of pores is a troublesome question because they will reduce the bearing area of the joint and accelerate the initiation of cracks, resulting in a significant reduction of the tensile strength. Based on these considerations, in this study, the effect of pores on laser-welded nuclear-grade FeCrAl alloy is investigated by quasi-in-situ tensile testing, and the fracture mechanism of the joint is revealed. The maximum ultimate tensile strength measured by the experiment is 550 MPa, and the elongation of welds is 9.6%. In addition, there are obvious stress concentrations and cracking phenomena generated in the vicinity of a pore. The joint is eventually fractured in the fusion line near the fusion zone. A large number of pores can be found at the fracture failure position from the fracture morphology observation, indicating that the pores are presumably to be the intrinsic reason for the cracking of the welded joints. © Published under licence by IOP Publishing Ltd.

关键词： Welds

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Thermo-mechanical analysis of the fuel assembly of Transformational Challenge reactor

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Progress in Nuclear Energy 2025年 188卷

作者： Zhu, Jun Li, Wenqiang Zhang, Qi Xin, Yong Li, Chenxi Wei, Chuanfu Teng, Diwang School of Mechanical Engineering Sichuan University Chengdu610065 China Electromechanical Equipment and Product Innovative Design Key Laboratory of Sichuan Province Chengdu610065 China National Key Laboratory of Nuclear Reactor Technology Nuclear Power Institute of China Chengdu610041 China

The Transformational Challenge reactor (TCR) is a novel high-temperature gas-cooled reactor based on advanced manufacturing technologies. In the reactor, the contact between fuel elements might lead to the maximum principal stress exceeding the safe stress limit, thereby affecting the reactor's safety. Therefore, it is necessary to evaluate the stress on fuel elements considering the contact situation. This paper divides the structural contact elements and employs the finite element method (FEM) for temperature analysis of fuel assemblies based on Computational Fluid Dynamics (CFD). Additionally, it conducts a stress analysis on eight layers of fuel within the fuel contact element unit cell. The results indicate that the maximum stress level of the fuel elements reaches 60.88 % of the tensile strength. The maximum stress point is located on the surface of the Internal cooling channel, where the thermal expansion of the fuel causes excessive mechanical stress due to radial compression. By considering initial gaps between the fuel elements in horizontal direction, the maximum stress is reduced, and the effectiveness of these gaps is verified. Stress evaluation was performed according to the ASME standards for SiC composite materials. All stress components were within the safe range, confirming the structural integrity. © 2025

关键词： Thermal stress

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A Discrete Numerical Study of the Effect of the Thickness and the Porosity of the Sand Cushion on the Impact Response Due to the Rockfall

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Computer Modeling in Engineering & sciences 2022年第3期130卷 1683-1698页

作者： Song Yuan Peng Zhao Liangpu Li Xibao Wang Jun Liu Bo Zhang Sichuan Communication Surveying&Design Institute Co. Ltd.Chengdu610065China Key Laboratory of Deep Underground Science and Engineering(Ministry of Education) College of Architecture and EnvironmentSichuan UniversityChengdu610065China Institute of New Energy and Low-Carbon Technology Sichuan UniversityChengdu610065China Institute of Science and Technology China Three Gorges CorporationBeijing100038China

The prevention and the reduction of the rockfall are the common measures of the prevention and the reduction of *** the rock-shed resists the impact of the rockfall,the force that acts on the structure consists of the cushion dead load and the impact-induced load,of which the dynamic process of the propagation of the impactinduced load is ***,we conducted a numerical study to investigate the impact of the *** the highly discrete characteristic of the sand,we developed a numerical model on the basis of the discrete element method(DEM).The numerical model,which simulation results were validated by the results of real-scale experiments,was used to investigate the dynamic response of the impact force of the rockfall and the transmission of the impact force under the different magnitude of the falling height and the different thickness of the sand *** results of our study indicated that the cushion thickness had little effect on the impact of the rockfall,and the dense sand cushion generated higher impact force than did the loose sand *** the high thickness enhanced the buffer performance of the sand cushion,the additional force induced by the dead load of sand cushion was ***,to determine the appropriate thickness of the sand cushion,we suggested designers consider the buffer performance and the dead load of the sand *** analysis presented in this paper provided a practical estimation of the impact-induced force of the thick sand cushion.

关键词： Rockfall impact DEM sand cushion thickness porosity impact force bottom force

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Spline-Based Stochastic Collocation Methods for Uncertainty Quantification in Nonlinear Hyperbolic PDEs

Spline-Based Stochastic Collocation Methods for Uncertainty...

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European Conference on Numerical Mathematics and Advanced Applications, ENUMATH 2023

作者： Chertock, Alina Iskhakov, Arsen S. Janajra, Safa Kurganov, Alexander Department of Mathematics North Carolina State University RaleighNC United States Department of Mechanical and Nuclear Engineering Kansas State University ManhattanKS United States Department of Mathematics Shenzhen International Center for Mathematics and Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology Shenzhen China

ISBN: (纸本)9783031861727

In this paper, we study the stochastic collocation (SC) methods for uncertainty quantification (UQ) in hyperbolic systems of nonlinear partial differential equations (PDEs). In these methods, the underlying PDEs are numerically solved at a set of collocation points in random space. A standard SC approach is based on a generalized polynomial chaos (gPC) expansion, which relies on choosing the collocation points based on the prescribed probability distribution and approximating the computed solution by a linear combination of orthogonal polynomials in the random variable. We demonstrate that this approach struggles to accurately capture discontinuous solutions, often leading to oscillations (Gibbs phenomenon) that deviate significantly from the physical solutions. We explore alternative SC methods, in which one can choose an arbitrary set of collocation points and employ shape-preserving splines to interpolate the solution in a random space. Our study demonstrates the effectiveness of spline-based collocation in accurately capturing and assessing uncertainties while suppressing oscillations. We illustrate the superiority of the spline-based collocation on two numerical examples, including the inviscid Burgers and shallow water equations. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

关键词： Normal distribution

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