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Effect of Si_3N_4 Addition on the mechanical Properties, Microstructures, and Wear Resistance of Ti-6Al-4V Alloy

Journal of Materials Science & Technology 2007年第2期23卷 257-261页

作者： Ruihua HU Montasser M. Dewidar Hyo-Jin KIM Jae-Kyoo LIM Henan University of Science and Technology Luoyang 471003 China Department of Mechanical Design Chonbuk National University Dokjin 1-664-14 Jeonju South Korea Department of Mechanical Design and Materials High Institute of Energy South Valley University Aswan Egypt Automobile High-Technology Research Institute Faculty of Mechanical and Aerospace System Engineering Chonbuk National University Dokjin 1-664-14 Jeonju South Korea

In order to improve the wear resistance of Ti-6Al-4V, different amounts of Si3N4 powder were added into the alloy powder and sintered at 1250℃. Porous titanium alloy with higher wear resistance was successfully fabricated. At sintering temperature, reaction took place and a new hard phase of Ti5Si3 formed. The mechanical properties of the fabricated alloys with different amounts of Si3N4 addition were investigated. The hardness of Ti-6Al-4V, which is the index of wear resistance, was increased by the addition of Si3N4. Amounts of Si3N4 addition have very significant influences on hardness and compressive strength. In present study,titanium alloy with 5 wt pct Si3N4 addition has 62% microhardness and 45% overall bulk hardness increase,respectively. In contrast, it has a 16.4% strength reduction. Wear resistance was evaluated by the weight loss during wear test. A new phase of Ti5Si3 was detected by electron probe microanalyzer （EPMA） and X-ray diffraction （XRD） method. The original Si3N4 decomposed during sintering and transformed into titanium silicide. Porous structure was achieved due to the sintering reaction.

关键词： Ti-6Al-4V Silicon nitride Sintering reaction mechanical properties

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Aerial refueling scheduling of multi-receiver and multi-tanker under spatial-temporal constraints for forest firefighting

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Chinese Journal of Aeronautics 2024年第5期37卷 71-91,I0001页

作者： Jing HUANG Jiaqi XING Jinrui REN Quan QUAN Youmin ZHANG Department of Information and Control Engineering Xi’an University of TechnologyXi’an 710048China Jiujiang Measuring Test Technology Research Institute Jiujiang 332000China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China School of Automation Xi’an University of Posts&TelecommunicationsShaanxiXi’an 710121China Department of Mechanical Industrial and Aerospace EngineeringConcordia UniversityMontreal H3G 1M8Canada

Forest fires pose a significant threat to human life and property,so the utilization of unmanned aircraft systems provides new ways for forest *** the constrained load capacities of these aircraft,aerial refueling becomes crucial to extend their operational time and *** order to address the complexities of firefighting missions involving multi-receiver and multi-tanker deployed from various airports,first,a fuel consumption calculation model for aerial refueling scheduling is established based on the receiver ***,two distinct methods,including an integrated one and a decomposed one,are designed to address the challenges of establishing refueling airspace and allocating tasks for *** methods aim to optimize total fuel consumption of the receivers and tankers within the aerial refueling scheduling *** optimization problem is established as nonlinear optimization models along with *** integrated method seamlessly combines refueling rendezvous point scheduling and tanker task allocation into unified *** has a complete solution space and excels in optimizing total fuel *** decomposed method,through the separation of rendezvous point scheduling and task allocation,achieves a reduced computational ***,this comes at the cost of sacrificing optimality by excluding specific feasible ***,numerical simulations are carried out to verify the feasibility and effectiveness of the proposed *** simulations yield insights crucial for the practical engineering application of both the integrated and decomposed methods in real-world *** comprehensive approach aims to enhance the efficiency of forest firefighting operations,mitigating the risks posed by forest fires to human life and property.

关键词： Aerial refueling Scheduling Planning Spatial-temporal constraint Firefighting

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Design and analysis of tubular linear machines with dual halbach arrays

Design and analysis of tubular linear machines with dual hal...

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2nd International Conference on engineering and Technology Innovation 2012, ICETI 2012

作者： Yan, Liang Zhang, Lei Yao, Nan Jiao, Zongxia Chen, I.-Ming Chen, Chin-Yin School of Automation Science and Electrical Engineering Beihang University Beijing China School of Mechanical and Aerospace Engineering Nanyang Technological University Singapore National Applied Research Laboratories Taiwan Ocean Research Institute Taiwan

ISBN: (纸本)9783037856123

Linear machines are widely employed in robotics, transportation and manufacturing industries because complex rotation-to-translation conversion mechanism is no longer required. This paper proposed a novel tubular linear machine with dual permanent magnet (PM) Halbach arrays to achieve high force output performance. Based on Lorentz force law, the magnetic force output and force ripple for three-phase winding linear machine is formulated in analytical way. By taking advantage of the analytical models, the force output is simulated with respect to the motion of the mover. Numerical result is then obtained to validate the analytical force models. In addition, based on the technology of non-dimensionalization, the mathematical force models are employed to analyze the influence among the structure parameters on the force output and force ripple for design purpose of the tubular linear machines. The study in this paper could contribute to the design analysis and optimization of electromagnetic linear machines with similar poles patterns. © (2013) Trans Tech Publications, Switzerland.

关键词： Permanent magnets

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Effect of nanoscale SiC particles on strength distribution of joined Si3N4 to inconel alloy

Effect of nanoscale SiC particles on strength distribution o...

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作者： Seo, Do Won Chi, Chang Heon Faculty of Mechanical and Aerospace System Eng. Engineering Research Institute Chonbuk Nat'l Univ. Jeonju Korea Republic of Division of Mechanical and Automobile Engineering Wonkwang Univ. Iksan Korea Republic of

Two-layered Si3N4SiC nano-composites with 50vol.% SiC have been fabricated by two-step sintering of a powder mixture of α-Si3N4 and carbon powder with a mean size of 13nm, and 5wt.% Y2O3. Nano-sized SiC particles were formed through reactions: carbon and surface SiO2 on the Si 3N4 particles, and carbon and Si3N4 particles. To combine the specific advantages of nanoscale ceramics with that of metals, they are often used together within one composite component. In this study, the fabrication and mechanical properties of a nanoscale SiC layer brazed with an Inconel alloy were investigated. It was shown that, with a variation of strain rate, the joints have a bending strength of 330-380MPa, and the deflection of the interlayer increases with increasing strain rate. The fracture types are classified into three groups;cracks grow into the metal-brazing filler layer, the ceramic-brazing filler layer or inside the ceramic.

关键词： Silicon nitride

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Data-Driven Parametric Design of Additively Manufactured Hybrid Lattice Structure for Stiffness and Wide-Band Damping Performance

Additive Manufacturing Frontiers

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Additive Manufacturing Frontiers 2025年

作者： Chenyang Li Shangqin Yuan Han Zhang Shaoying Li Xinyue Li Jihong Zhu State IJR Center of Aerospace Design and Additive Manufacturing School of Mechanical Engineering Northwestern Polytechnical University Xi'an 710072 China Key Laboratory of Metal High-Performance Additive Manufacturing and Innovative Design MIIT China Northwestern Polytechnical University Xi'an 710072 China Institute of Intelligence Material and Structure Unmanned System Research Institute Northwestern Polytechnical University Xi'an 710072 China Aircraft Strength Research Institute of China Xi'an 710065 China Modern Control Technology Research Institute Xi'an 710065 China

The outstanding comprehensive mechanical properties of newly developed hybrid lattice structures make them useful in engineering applications for bearing multiple mechanical loads. Additive-manufacturing technologies make it possible to fabricate these highly spatially programmable structures and greatly enhance the freedom in their design. However, traditional analytical methods do not sufficiently reflect the actual vibration-damping mechanism of lattice structures and are limited by their high computational cost. In this study, a hybrid lattice structure consisting of various cells was designed based on quasi-static and vibration experiments. Subsequently, a novel parametric design method based on a data-driven approach was developed for hybrid lattices with engineered properties. The response surface method was adopted to define the sensitive optimization target. A prediction model for the lattice geometric parameters and vibration properties was established using a backpropagation neural network. Then, it was integrated into the genetic algorithm to create the optimal hybrid lattice with varying geometric features and the required wide-band vibration-damping characteristics. Validation experiments were conducted, demonstrating that the optimized hybrid lattice can achieve the target properties. In addition, the data-driven parametric design method can reduce computation time and be widely applied to complex structural designs when analytical and empirical solutions are unavailable.

关键词： Hybrid lattice structure Data-driven wide-band damping Machine-learning method

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A Comparison between Direct and Indirect Laser Sintering of Metals

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Journal of Materials Science & Technology 2008年第2期24卷 227-232页

作者： Montasser M.Dewidar Jae-Kyoo LIM K.W.Dalgarno Department of Mechanical Design and Materials High Institute of EnergySouth Valley UniversityAswanEgypt Automobile Hi-Technology Research Intitute Faculty of Mechanical & Aerospace System EngineeringChonbuk National UniversityDuckjin 1-664-14JeonjuJB 561-756South Korea School of Mechanical and Systems Engineering Stephenson BuildingClaremont RoadNewcastle UniversityNewcastle upon Tyne NE1 7RUUnited Kingdom

Layer manufacture technologies are gaining increasing attention in the manufacturing for the production of polymer mould tooling. Layer manufacture techniques can be used in this potential manufacturing area to produce tooling either indirectly or directly, and powder metal based layer manufacture systems are considered as an effective way of producing rapid tooling. mechanical properties and accuracy are critical for tooling. This paper reports the results of an experimental study examining the potential of layer manufacturing processes to deliver production tooling for polymer manufacture. A comparison between indirectly selective laser sintering and directly selective laser sintering to provide the tooling was reported. Three main areas were addressed during the study： mechanical strength, accuracy, and build rate. Overviews of the results from the studies were presented.

关键词： Selective laser sintering Layer manufacture Mould tooling Rapid tooling

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DeepONet-Based Bank Angle Profiles Design for Mars Entry with Actuator Constraints

DeepONet-Based Bank Angle Profiles Design for Mars Entry wit...

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2024 China automation Congress, CAC 2024

作者： Tang, Bo Li, Yajing Mei, Jie Wu, Weiren Institute of Space Science and Applied Technology Harbin Institute of Technology Shenzhen Guangdong Shenzhen518055 China Shanghai Institute of Aerospace System Engineering Shanghai201109 China School of Mechanical Engineering and Automation Harbin Institute of Technology Shenzhen Guangdong Shenzhen518055 China

ISBN: (纸本)9798350368604

The determination of the bank angle profile is crucial for Mars atmospheric entry guidance. A significant limitation of existing bank angle profile construction methods is their neglect of the dynamic process of the bank angle. This paper introduces a novel parameterized bank angle profile construction method using deep operator networks (DeepONet). Initially, a design strategy for parameterized bank angle profiles, considering the dynamic characteristics of the bank angle, is presented. The bank angle profile is then modeled as an operator dependent on specific parameters. The DeepONet, which is tailor-made for learning operators, is utilized to construct parameterized bank angle profiles of unknown analytical forms. To handle rapid changes in the bank angle, Fourier feature layers are incorporated into the network to encode the time inputs. Numerical simulations demonstrate that the proposed network can effectively approximate the desired bank angle profile. In the guidance design, using the proposed network-based parameterized bank angle profile can effectively reduce the deviation between the predicted and actual flight states. © 2024 IEEE.

关键词： Parameterization

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A novel simple humidity sensor constructed by sandwiched cantilever

A novel simple humidity sensor constructed by sandwiched can...

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2006 5th IEEE Conference on Sensors

作者： Chen, Rex Chu, N-Hsun Lee, Chia-Yen Chen, Hao-Jen Cheng, Wood-Hi Micro-system Technology Center Industrial Technology Research Institute Tainan Taiwan Department of Mechanical and Automation Engineering Da-Yeh University Changhua Taiwan Institute of Electro-optical Engineering NSYSU Kaoshiung Taiwan

ISBN: (纸本)1424403766

This paper presents a novel humidity sensing mechanism. A simple sandwiched cantilever fabricated by traditional MEMS (Microelectromechanic Syetems) process is proposed in this study. During the operation of humidity sensing, the polyimide-sensing layer, top layer of the sandwiched micro-cantilever, swells and the induced compressive stress pushes the tip of cantilever to deflect downward. To systematically investigate the performance of humidity sensor, three items were conducted in this study including response curve, time response, and hysteresis. The simple sensing mechanism had been verified and yielded a high average response time of 0.7 second during humidity range from 65%RH to 95%RH. © 2006 IEEE.

关键词： Humidity sensors

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Satellite attitude determination and estimation using two star trackers

Satellite attitude determination and estimation using two st...

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AIAA Guidance, Navigation, and Control Conference

作者： Bae, Jonghee Kim, Youdan Kim, Hee Seob Seoul National University Seoul 151-742 Korea Republic of Korea Aerospace Research Institute Daejeon 305-333 Korea Republic of School of Mechanical and Aerospace Engineering Institute of Advanced Aerospace Technology Korea Republic of KOMPSAT-3 System Engineering and Integration Department Korea Republic of

ISBN: (纸本)9781600869624

This paper deals with the attitude determination and the estimation algorithm of the satellite with two star trackers. The estimation accuracy of the attitude using primary star tracker can be improved by utilizing the attitude information of the secondary (back up) star tracker. Therefore, the attitude determination algorithm using two star trackers is proposed to enhance the accuracy of the attitude estimation. The unscented Kalman filter is used to estimate the attitude of the nonlinear satellite systems, and the decentralized scheme in a federated configuration is adopted so that sensor fault can be easily detected and isolated by employing the fault detection and isolation algorithm. Using the proposed algorithm, the satellite can continuously perform its mission despite the fault occurrence of the attitude sensor. Numerical simulation is performed to verify the effectiveness of the proposed attitude determination and estimation algorithm. Copyright © 2010 by the American institute of Aeronautics and Astronautics, Inc. All rights reserved.

关键词： Fault detection

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Discussion on the Design of Low-cost Spacecraft Avionics based on COTS Technology

Discussion on the Design of Low-cost Spacecraft Avionics bas...

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7th International Conference on Electronics Technology, ICET 2024

作者： Chen, Chaoji Yin, Yaobao Yang, Jiang Wang, Dan Dong, Zhenhui Jia, Yuchen Beijing Institute of Spacecraft System Engineering Beijing China Tongji University School of Mechanical Engineering Shanghai China Shandong Aerospace Electronics Technology Research Institute Yantai China

ISBN: (纸本)9798350363951

Because of the benefits of excellent performance, ease of acquisition and low cost, COTS (commercial off-the-shelf) components have been gradually utilized in spacecraft. They will play an increasingly important role in space applications in the future. This study first investigates the situation of COTS technology-based spacecraft avionics both domestically and internationally, analyzing the necessity of COTS technology applied in the space field and its problems, and it illustrates that COTS technology is a significant means of enhancing the performance of spacecraft avionics in the future. Secondly, an intelligent avionics architecture for low-cost and highly reliable spacecraft based on COTS technology is proposed, considering the requirements of spacecraft avionics. Then, aiming at the challenges of using COTS components extensively in space, the reliability assurance methods for COTS components are suggested from the perspectives of reliability design methods and reliability prediction analysis. Finally, an on-orbit application example of the COTS component is provided, which can serve as a reference for application of the other spacecraft. © 2024 IEEE.

关键词： Space applications

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