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Numerical Simulation for Arc Windshields of Aircrafts Subjected to Bird Impact

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上海交通大学学报 2004年第z2期38卷 147-151页

作者： Yao xiaohu z.ao Longmao Liu Xiaoming Institute of Applied Mechanics Taiyuan University of Technology China College of Traffic and Communications South China University of Technology China Institute of Applied Mechanics Taiyuan University of Technology China Chengdu Aircraft Industry Company China

A finite element model including full-scale circular arc windshield glass and the relative parts of the military plane is established in this paper. The model is analyzed by using an explicit element code LS-DYNA3D for analyzing the nonlinear dynamic response of structures. The data in aspects of displacement, strain, stress and contact force in the process of deformation are obtained. The deformation and failure mechanism of circular arc windshield glass are discussed. The possible location at which failure may take place is given. The valuable data are provided for designing,researching and producing new windshields with high crashworthiness.

关键词： bird impact arc windshield dynamic response liquid-solid coupling

Risk-constrained Energy Management Strategy for a Commercial Campus Considering Comprehensive Reserves Against Islanding Conditions

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CSEE Journal of Power and Energy Systems 2023年第5期9卷 1797-1807页

作者： zheming Liang Desong Bian xiaohu zhang Di Shi GEIRI North America San JoseCAUSA.Z.M.Liang is also with Huaneng Renewables Co.Ltd.Beijing 100036China

This paper proposes an optimal risk-constrained energy management strategy for commercial buildings in a commercial campus with islanding *** goal is to minimize the total operation and maintenance costs,while maximizing comprehensive comfort levels for the occupants.A two-stage riskconstrained,scenario-based stochastic optimization approach is adopted to handle various uncertainties associated with the energy management process,such as power generation of rooftop solar panels,arrival state-of-charges,and arrival/departure time of plug-in electric vehicles,intermittent load demand,and uncertain grid-connection conditions.A conditional-valueat-risk method is introduced to provide a risk-averse energy management *** face the challenge of both reducing the computational burden and maintaining the accuracy of the stochastic programming,an advanced scenario reduction method is *** simulation results validate the effectiveness of the proposed energy management strategy for minimizing total operating and maintenance costs of commercial buildings with islanding capabilities,while maximizing comprehensive comfort levels of the occupants.

关键词： Comprehensive comfort levels CVaR energy management islanding capability reserve stochastic programming uncertainty

Unique Duplex Microstructure and Porosity Effect on Mechanical Properties of AlCoCrFeNi_(2.1) Eutectic High-Entropy Alloys Processed by Selective Laser Melting

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Acta Metallurgica Sinica(English Letters) 2023年第9期36卷 1465-1481页

作者： Liwei Lan Wenxian Wang zeqin Cui xiaohu Hao College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan030024China Key Laboratory of Interface Science and Engineering in Advanced Materials Taiyuan University of TechnologyMinistry of EducationTaiyuan030024China Shanxi–zhejiang University New Materials and Chemical Research Institute Taiyuan030032China

Selective laser melting(SLM)was performed on AlCoCrFeNi_(2.1) eutectic high-entropy alloys(EHEAs),and the unique duplex microstructure and porosity were investigated as well as the negative effect on mechanical *** printed AlCoCrFeNi_(2.1) EHEAs is composed of face-centered cubic and BCC/B2 phases,and the surface texture of samples perpendicular to and parallel to the building direction is *** the bottom of the molten pool to the inside,the structure changes from dendrites to columnar crystals and then to cellular crystals,the distribution of elements in and around the molten pool is uniform,and there is no element *** surface hardness of as-printed AlCoCrFeNi_(2.1) EHEAs is higher than that of as-cast ones due to the grain refinement strengthening,and there is anisotropy in different surface hardness,the highest hardness is 580 HV(X–Y plane)and 560 HV(X–z plane).The reduction of bearing area and tip stress concentration caused by pores have adverse effects on the tensile strength and elongation of the alloy,the ultimate tensile strength increased from 1060 to 1289 MPa.

关键词： Selective laser melting Eutectic high-entropy alloys Metallurgical porosity Microstructure evolution Grains and interfaces

Alternating electric field actuated oscillating behavior of liquid metal and its application

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Science China(Technological Sciences) 2016年第4期59卷 597-603页

作者： YANG xiaohu TAN SiCong YUAN Bin LIU Jing Beijing Key Lab of Cryo Biomedical Engineering and Key Lab of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of Sciences Department of Biomedical Engineering School of Medicine Tsinghua University

As a class of newly emerging functional material, Gallium based liquid metals have attracted increasing attentions in many fields, such as chip cooling, printed electronics and microfiuidics, etc. Particularly, the motion control of liquid metal droplet has been recently tried for its importance in microelectromechanical system （MEMS）, microfluidics and potential use in micro-machine or reconfigurable soft robot. This paper is dedicated to explore the motion behavior of liquid metal droplet under AC electric field. The quickly induced oscillation phenomena of liquid metal droplet and surrounding electrolyte solution were observed and the major factors to influence such behaviors are theoretically interpreted and experimentally investigated, including the size of the liquid metal droplet, electrode voltage, electrolyte solution concentration and AC signal frequency etc. Moreover, some typical features to distinguish AC filed actuation with DC field are observed, such as intensive fluid waving induced by the resonance stimulation, and the efficient inhibition of solution electrolysis. Finally, two important applications of adopting AC induced surface oscillation of liquid metal droplet to develop solution mixer as well as fluidic pump were demonstrated which successfully avoid gas generation inside electrolyte environment. The bulk oscillation effects of liquid metal as clarified here could be very useful in a variety of areas such as solution disturbance and mixing, and fluid oscillator or pump etc.

关键词： liquid metal motion control AC actuation fluid oscillation and waving resonance effect fluidic pump solution mixer

Image edge detection based on beamlet transform

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Journal of Systems Engineering and Electronics 2009年第1期20卷 1-5页

作者： Li Jing Huang Peikang Wang xiaohu Pan Xudong China Aerospace Science 8z Industry Corporation Beijing 100854 P. R. China

Combining beamlet transform with steerable filters, a new edge detection method based on line gradient is proposed. Compared with operators based on point local properties, the edge-detection results with this method achieve higher SNR and position accuracy, and are quite helpful for image registration, object identification, etc. Some edge-detection experiments on optical and SAR images that demonstrate the significant improvement over classical edge operators axe also presented. Moreover, the template matching result based on edge information of optical reference image and SAR image also proves the validity of this method.

关键词： edge detection beamlet transform steerable filters optical image SAR image.

Anisotropy study of the microstructure and properties of AlCoCrFeNi2.1 eutectic high entropy alloy additively manufactured by selective laser melting

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Journal of Materials Science & Technology 2022年第34期129卷 228-239页

作者： Liwei Lan Wenxian Wang zeqin Cui xiaohu Hao Dong Qiu College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Interface Science and Engineering in Advanced Materials Taiyuan University of TechnologyMinistry of EducationTaiyuan 030024China Shanxi-zhejiang University New Materials and Chemical Research Institute Taiyuan 030024China Centre for Additive Manufacturing School of EngineeringRMIT UniversityMelbourneVictoria 3001Australia

The AlCoCrFeNi2.1 eutectic high-entropy alloy(EHEA) was prepared by selective laser melting(SLM), focusing on the anisotropy of microstructure and mechanical performance. The AlCoCrFeNi2.1 EHEA printed by SLM has face-centered cubic(FCC) and body-centered cubic(BCC)/B2 phases, and the FCC phase accumulates at the boundary of the molten pool. With the increase in volumetric energy density(VED), the content of the FCC phase parallel to the surface in the direction of the building increases from 30.9% to 41%. The X–z plane mainly produces columnar crystals along the temperature gradient, while a large number of equiaxed crystals are produced in the X–Y direction. When the volume energy density is 157 k J/mol(VED 157), the average grain size is 1.33 μm for BCC and 1.14 μm for FCC, which is significantly smaller than other preparation methods. Due to defect distribution and size, the microhardness of the X–Y plane is generally higher than that of the X–z plane, with maximum hardnesses of 660 HV and 655 HV, respectively, which is much higher than those of traditionally manufactured *** compression performance of SLM process AlCoCrFeNi2.1 EHEAs shows maximum yield strength of 1567 MPa, and the ultimate compressive strength can reach 3276 MPa.

关键词： Selective laser melting High-entropy alloys Anisotropy Metallurgical defects Microstructure evolution

Low-complexity optimal spatial channel pairing for AF-based multi-pair two-way relay networks

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Science China(Information Sciences) 2014年第10期57卷 46-55页

作者： SHU Feng CHEN Yu YOU xiaohu LU JinHui School of Electronic and Optical Engineering Nanjing University of Science and Technology National Mobile Communications Research Laboratory Southeast University Ministerial Key Laboratory of JGMT Nanjing University of Science and Technology

This paper considers a multi-pair two-way relay system with multi-antenna users and proposes a low-complexity optimal spatial channel pairing(SCP) strategy at the relay station(RS) for such a system. The proposed SCP scheme, following the BD-like beamformer at RS, pairs the uplink spatial subchannels of each user pair with the corresponding downlink spatial subchannels by maximizing sum-rate(Max-SR). Furthermore, a new mathematical inequality(arrangement inequalities of a product) is developed and applied to obtain sufficient and necessary conditions for achieving Max-SR-SCP. This also yields a simple low-complexity implementation of the proposed SCP in contrast to the NP-hard complexity of the original Max-SR-SCP problem. Simulation results illustrate that the proposed Max-SR-SCP achieves substantial sum-rate gains over other pairing schemes.

关键词： multipair two-way relay spatial channel pairing maximizing sum-rate arrangement inequalities of product relaying station

Au-Ag Alloy Nanoporous Nanotubes

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Nano Research 2009年第5期2卷 386-393页

作者： xiaohu Gu Liqiang Xu Fang Tian Yi Ding School of Chemistry and Chemical Engineering Key Laboratory of Liquid Structure and Heredity of MaterialsMinistry of EducationShandong UniversityJinan 250100China

Metallic nanostructures with hollow interiors or tailored porosity represent a special class of attractive materials with intriguing chemicophysical *** paper presents the fabrication of a new type of metallic nanoporous nanotube structure based on a facile and effective combination of nanocrystal growth and surface *** controlling the individual steps involved in this process,such as nanowire growth,surface modification,thermal diffusion,and dealloying,one-dimensional(1-D)metallic nanostructures can be prepared with tailored structural features and pre-designed *** tubular and porous nanostructures show distinct optical properties,such as tunable absorption in the near-infrared region,and enhanced capability for electrochemiluminescence signal amplification,which make them particularly desirable as novel 1-D nano-carriers for biomedical,drug delivery and sensing applications.

关键词： Nanoporous nanotube gold optical properties electrochemiluminescence

Application of novel force control strategies to enhance robotic abrasive belt grinding quality of aero-engine blades

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Chinese Journal of Aeronautics 2019年第10期32卷 2368-2382页

作者： xiaohu XU Dahu zHU Haiyang zHANG Sijie YAN Han DING State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of TechnologyWuhan 430074China Wuxi CRRC Times Intelligent Equipment Co. Ltd.Wuxi 214174China

Robotic belt grinding has emerged as a finishing process in recent years for machining components with high surface finish and *** surface machining consistency,however,is difficult to be guaranteed in such a *** overcome this problem,a method of hybrid force-position control combined with PI/PD control is proposed to be applied in robotic abrasive belt grinding of complex *** signals are firstly obtained and transformed to force information with signal conditioning ***,zero drift and gravity compensation algorithms are presented to calibrate the F/T transducer which is installed on the robot ***,a force control strategy combining hybrid force-position control with PI/PD control is introduced to be employed in robotic abrasive belt grinding operations where the force control law is applied to the z direction of the tool frame and the positon control law is used in the X direction of the tool ***,the accuracy of the F/T transducer and the robotic force control system is analyzed to ensure the stability and reliability of force control in the robotic grinding ***,two typical cases on robotic belt grinding of a test workpiece and an aero-engine blade are conducted to validate the practicality and effectiveness of the force control technology proposed.

关键词： Gravity compensation Hybrid force-position control PI/PD control Robotic belt grinding zero drift compensation