In the third decade of the 21st century,the aerospace field is evolving at an unprecedented pace towards intelligence and autonomy.As competition for space resource development intensifies,breakthroughs in near-space ...In the third decade of the 21st century,the aerospace field is evolving at an unprecedented pace towards intelligence and autonomy.As competition for space resource development intensifies,breakthroughs in near-space vehicle technology emerge,and the concept of drone swarm warfare matures,traditional rule-based and experience-driven battlefield situation awareness models are struggling to meet the demands of complex adversarial environments.This special issue brings together the latest research findings from fields such as computer science and technology,electronic engineering,and cognitive science,systematically exploring the cognitive revolution driven by the deep integration of next-generation artificial intelligence and aerospace engineering,all centered around the core theme of"Intelligent Situation Awareness"(ISA).展开更多
Due to advantages of high power-conversion efficiency(PCE), large power-to-weight ratio(PWR), low cost and solution processibility, flexible perovskite solar cells(f-PSCs) have attracted extensive attention in recent ...Due to advantages of high power-conversion efficiency(PCE), large power-to-weight ratio(PWR), low cost and solution processibility, flexible perovskite solar cells(f-PSCs) have attracted extensive attention in recent years. The PCE of f-PSCs has developed rapidly to over 25%, showing great application prospects in aerospace and wearable electronic devices. This review systematically sorts device structures and compositions of f-PSCs, summarizes various methods to improve its efficiency and stability recent years. In addition, the applications and potentials of f-PSCs in space vehicle and aircraft was discussed. At last, we prospect the key scientific and technological issues that need to be addressed for f-PSCs at current stage.展开更多
After the design of aerospace products is completed,a manufacturability assessment needs to be conducted based on 3D model's features in terms of modeling quality and process design,otherwise the cost of design ch...After the design of aerospace products is completed,a manufacturability assessment needs to be conducted based on 3D model's features in terms of modeling quality and process design,otherwise the cost of design changes will increase.Due to the poor structure and low reusability of product manufacturing feature information and assessment knowledge in the current aerospace product manufacturability assessment process,it is difficult to realize automated manufacturability assessment.To address these issues,a domain ontology model is established for aerospace product manufacturability assessment in this paper.On this basis,a structured representation method of manufacturability assessment knowledge and a knowledge graph data layer construction method are proposed.Based on the semantic information and association information expressed by the knowledge graph,a rule matching method based on subgraph matching is proposed to improve the precision and recall.Finally,applications and experiments based on the software platform verify the effectiveness of the proposed knowledge graph construction and rule matching method.展开更多
Aerospace optical cables and fiber-optic connectors have numerous advantages(e.g.,low loss,wide transmission frequency band,large capacity,light weight,and excellent resistance to electromagnetic interference).They ca...Aerospace optical cables and fiber-optic connectors have numerous advantages(e.g.,low loss,wide transmission frequency band,large capacity,light weight,and excellent resistance to electromagnetic interference).They can achieve optical communication interconnections and high-speed bidirectional data transmission between optical terminals and photodetectors in space,ensuring the stability and reliability of data transmission during spacecraft operations in orbit.They have become essential components in high-speed networking and optically interconnected communications for spacecrafts.Thermal stress simulation analysis is important for evaluating the temperature stress concentration phenomenon resulting from temperature fluctuations,temperature gradients,and other factors in aerospace optical cables and connectors under the combined effects of extreme temperatures and vacuum environments.Considering this,advanced optical communication technology has been widely used in high-speed railway communication networks to transmit safe,stable and reliable signals,as high-speed railway optical communication in special areas with extreme climates,such as cold and high-temperature regions,requires high-reliability optical cables and connectors.Therefore,based on the finite element method,comprehensive comparisons were made between the thermal distributions of aerospace optical cables and J599III fiber optic connectors under different conditions,providing a theoretical basis for evaluating the performance of aerospace optical cables and connectors in space environments and meanwhile building a technical foundation for potential optical communication applications in the field of high-speed railways.展开更多
The aerospace community widely uses difficult-to-cut materials,such as titanium alloys,high-temperature alloys,metal/ceramic/polymer matrix composites,hard and brittle materials,and geometrically complex components,su...The aerospace community widely uses difficult-to-cut materials,such as titanium alloys,high-temperature alloys,metal/ceramic/polymer matrix composites,hard and brittle materials,and geometrically complex components,such as thin-walled structures,microchannels,and complex surfaces.Mechanical machining is the main material removal process for the vast majority of aerospace components.However,many problems exist,including severe and rapid tool wear,low machining efficiency,and poor surface integrity.Nontraditional energy-assisted mechanical machining is a hybrid process that uses nontraditional energies(vibration,laser,electricity,etc)to improve the machinability of local materials and decrease the burden of mechanical machining.This provides a feasible and promising method to improve the material removal rate and surface quality,reduce process forces,and prolong tool life.However,systematic reviews of this technology are lacking with respect to the current research status and development direction.This paper reviews the recent progress in the nontraditional energy-assisted mechanical machining of difficult-to-cut materials and components in the aerospace community.In addition,this paper focuses on the processing principles,material responses under nontraditional energy,resultant forces and temperatures,material removal mechanisms,and applications of these processes,including vibration-,laser-,electric-,magnetic-,chemical-,advanced coolant-,and hybrid nontraditional energy-assisted mechanical machining.Finally,a comprehensive summary of the principles,advantages,and limitations of each hybrid process is provided,and future perspectives on forward design,device development,and sustainability of nontraditional energy-assisted mechanical machining processes are discussed.展开更多
Good distribution of samples and weights can improve the computational accuracy and efficiency in the stochastic response analyses of aerospace problems with uncertain parameters.This work proposes a new Generalized L...Good distribution of samples and weights can improve the computational accuracy and efficiency in the stochastic response analyses of aerospace problems with uncertain parameters.This work proposes a new Generalized L2 Discrepancy based on a General Point(GL2D-GP)for generating samples and their corresponding weights.The proposed GL2D-GP is an extension of the existing discrepancy by introducing the non-same weights and a smaller box to measure probability errors.Minimizing the GL2D-GP can yield a weight optimization formula that generates a set of optimal non-identical weights for a given sample set.Through minimizing the GL2D-GP assigned to the set of optimal non-same weights,a new sample and weight generation method is developed.In the proposed method,the samples can be easily generated in terms of the generalized Halton formula with a series of optimal permutation vectors which are found by the intelligent evolutionary algorithm.Once the sample set is obtained,the optimal weights can be generated in terms of the weight optimization formula.Five numerical examples are presented to verify the high accuracy,efficiency,and strong robustness of the proposed sample generation method based on GL2D-GP.展开更多
A prescribed performance control scheme based on the three-inflection-point hyperbolic function and predefined time performance function is proposed to solve the trajectory tracking problem of the forward-tilting morp...A prescribed performance control scheme based on the three-inflection-point hyperbolic function and predefined time performance function is proposed to solve the trajectory tracking problem of the forward-tilting morphing aerospace vehicle with time-varying actuator faults.To accurately estimate the loss degree of actuator faults,an immersion and invariance observer based on the predefined time dynamic scale factor is designed to estimate and compensate it.A composite dynamic sliding mode surface is designed using a three-inflection-point hyperbolic function,and a novel three-inflection-point sliding mode control framework is proposed.The convergent domain of the sliding manifold is adjusted by parameters,and the system error convergence is controllable.A transfer function is designed to eliminate the sensitivity of the three-inflection-point hyperbolic sliding mode to the unknown initial state,and combined with the barrier Lyapunov function,and the performance constraint of the system is realized.The global asymptotic stability of the system is demonstrated using a strict mathematical proof.The effectiveness and superiority of the proposed control scheme are proven by simulation experiments.展开更多
To improve the computational efficiency and accuracy of multi-objective reliability estimation for aerospace engineering structural systems,the Intelligent Vectorial Surrogate Modeling(IVSM)concept is presented by fus...To improve the computational efficiency and accuracy of multi-objective reliability estimation for aerospace engineering structural systems,the Intelligent Vectorial Surrogate Modeling(IVSM)concept is presented by fusing the compact support region,surrogate modeling methods,matrix theory,and Bayesian optimization strategy.In this concept,the compact support region is employed to select effective modeling samples;the surrogate modeling methods are employed to establish a functional relationship between input variables and output responses;the matrix theory is adopted to establish the vector and cell arrays of modeling parameters and synchronously determine multi-objective limit state functions;the Bayesian optimization strategy is utilized to search for the optimal hyperparameters for modeling.Under this concept,the Intelligent Vectorial Neural Network(IVNN)method is proposed based on deep neural network to realize the reliability analysis of multi-objective aerospace engineering structural systems synchronously.The multioutput response function approximation problem and two engineering application cases(i.e.,landing gear brake system temperature and aeroengine turbine blisk multi-failures)are used to verify the applicability of IVNN method.The results indicate that the proposed approach holds advantages in modeling properties and simulation performances.The efforts of this paper can offer a valuable reference for the improvement of multi-objective reliability assessment theory.展开更多
Uncertainty Quantification(UQ)is essential in aerospace systems as system performance is high sensitive to uncertainties associated with physics,materials,environments,models,and so forth.While recent advancements in ...Uncertainty Quantification(UQ)is essential in aerospace systems as system performance is high sensitive to uncertainties associated with physics,materials,environments,models,and so forth.While recent advancements in UQ across various engineering fields have introduced new research directions,significant challenges persist in developing methods to address high-dimensional,strongly coupled uncertainties and sparse experimental data.UQ has emerged as an important issue to be addressed in simulation-based aerospacedesign.展开更多
Nowadays,the internal structure of spacecraft has been increasingly complex.As its“lifeline”,cables require extensive manpower and resources for manual testing,and it is challenging to quickly and accurately locate ...Nowadays,the internal structure of spacecraft has been increasingly complex.As its“lifeline”,cables require extensive manpower and resources for manual testing,and it is challenging to quickly and accurately locate quality problems and find solutions.To address this problem,a knowledge graph based method is employed to extract multi-source heterogeneous cable knowledge entities.The method utilizes the bidirectional encoder representations from transformers(BERT)network to embed word vectors into the input text,then extracts the contextual features of the input sequence through the bidirectional long short-term memory(BiLSTM)network,and finally inputs them into the conditional random field(CRF)network to predict entity categories.Simultaneously,by using the entities extracted by this model as the data layer,a knowledge graph based method has been constructed.Compared to other traditional extraction methods,the entity extraction method used in this study demonstrates significant improvements in metrics such as precision,recall and an F1 score.Ultimately,employing cable test data from a particular aerospace precision machining company,the study has constructed the knowledge graph based method in the field to achieve visualized queries and the traceability and localization of quality problems.展开更多
目的研究Aerospace Medicine and Human Performance更名前后的主要报道方向、国别、发文机构的变化情况等,以期为国内同行提供参考。方法主要利用CiteSpace的共词网络功能来对期刊报道方向、发刊国别、发文机构等变化进行分析。数据来...目的研究Aerospace Medicine and Human Performance更名前后的主要报道方向、国别、发文机构的变化情况等,以期为国内同行提供参考。方法主要利用CiteSpace的共词网络功能来对期刊报道方向、发刊国别、发文机构等变化进行分析。数据来自Web of Science核心合集的SCI拓展版,以期刊名“Aviation Space and Environmental Medicine”检索,时间跨度为1991年1月1日至2014年12月31日,剔除征稿启事、会议通知等非学术文献。导入NoteExpress软件进行去重,共有4830篇文章。该刊于2015年更名为“Aerospace Medicine and Human Performance”,检索策略为:时间跨度为2015年1月1日至2023年6月13日,数据清洗方法同上,共检索到1076篇文章。结果(1)主要发文机构:更名前主要供稿机构为美国空军(160篇)、美国国防部(93篇)和美国宇航局(NASA,77篇);更名后主要供稿机构未发生变化,但发文数量均较更名前减少,美国空军47篇,美国国防部24篇,NASA 24篇。(2)主要关键词对比:更名后主要关键词与飞行、航天相关的连接强度显著增加,而对一般健康问题的关注相对减少,出现了spaceflight、air travel等直接与飞行行为相关的内容。(3)主要国别:更名前美国发文2411篇(49.91%)、加拿大发文314篇(6.50%)、英国发文279篇(5.77%)、法国发文167篇(3.45%)、德国发文160篇(3.31%);更名后美国发文501篇(46.56%)、英国发文98篇(9.10%)、中国发文54篇(5.01%)、加拿大发文53篇(4.92%)、法国发文42篇(3.90%)。(4)年均发文量:根据检索结果,更名前共24年,年均发文201篇;更名后从2015年至本文检索截止时间共8.5年,年均发文127篇,年均报道量下降较多。(5)影响因子:截止2014年更名前共发文164篇,影响因子1.0051(含自引);2016年是该刊更名有影响因子等统计数据的第一年,共发文132篇,影响因子0.8250;2022年发文109篇,影响因子1.0001(含自引)。综合考量发文量和影响因子,该刊的综合影响力更名后并无显著提升。结论该刊在更名后,对于飞行环境的影响报道有所减少,主要讨论范围从之前的所有飞行类型聚焦为以太空飞行为主,关于飞行行为对人体健康的影响和绩效表现的报道大幅增长,同时也增加了关于飞行装备对飞行安全影响的讨论。随着航空航天技术的进步和航空装备的发展,更深入地探讨航空活动中环境因素对人体长时间复合作用的影响是必然。在该刊更名后,我国的发文数量排名第三,也在一定程度上说明存在高质量原创性成果外流的情况。我国期刊在坚持刊物原有特色的前提下,根据领域研究的发展,与时俱进,探索可持续发展的办刊模式;要进一步明确期刊定位与服务对象,以国家重大需求为导向,聚焦航空航天领域前沿、热点,适时调整栏目设置,提升期刊的学术质量和学科影响力,打造高质量的学术交流平台。展开更多
Future aerospace vehicles （ASV） are designed to fly in both inner and extra atmospheric fields, which requires autonomous adaptability to the uncertainties emanated from abrupt faults and continuously time-varying e...Future aerospace vehicles （ASV） are designed to fly in both inner and extra atmospheric fields, which requires autonomous adaptability to the uncertainties emanated from abrupt faults and continuously time-varying environments. An autonomous control reconfiguration scheme is presented for ASV to deal with the uncertainties on the base of control effectiveness estimation. The on-line estimation methods for the time-varying control effectiveness of linear control system are investigated. Some sufficient conditions for the estimable system are given for different cases. There are proposed corresponding on-line estimation algorithms which are proved to be convergent and robust to noise using the least-square-based methods. On the ground of fuzzy logic and linear programming, the control allocation algorithms, which are able to implement the autonomous control reconfiguration through the redundant actuators, are put forward. Finally, an integrated system is developed to verify the scheme and algorithms by way of numerical simulation and analysis.展开更多
Thanks to recent advances in manufacturing technology, aerospace system designers have many more options to fabricate high-quality, low-weight, high-capacity, cost-effective filters. Aside from traditional methods suc...Thanks to recent advances in manufacturing technology, aerospace system designers have many more options to fabricate high-quality, low-weight, high-capacity, cost-effective filters. Aside from traditional methods such as stamping, drilling and milling, many new approaches have been widely used in filter-manufacturing practices on account of their increased processing abilities. How- ever, the restrictions on costs, the need for studying under stricter conditions such as in aggressive fluids, the complicity in design, the workability of materials, and others have made it difficult to choose a satisfactory method from the newly developed processes, such as, photochemical machining （PCM）, photo electroforming （PEF） and laser beam machining （LBM） to produce small, inexpensive, lightweight aerospace filters. This article appraises the technical and economical viability of PCM, PEF, and LBM to help engineers choose the fittest approach to turn out aerospace filters.展开更多
Aerospace manufacturing SMEs are continuously facing the challenge on managing their supply chain and complying with the aerospace manufacturing quality standard requirement due to their lack of resources and the natu...Aerospace manufacturing SMEs are continuously facing the challenge on managing their supply chain and complying with the aerospace manufacturing quality standard requirement due to their lack of resources and the nature of business. In this paper, the ERP system based approach is presented to quality control and assurance work in light of seamless integration of in-process production data and information internally and therefore managing suppliers more effectively and efficiently. The Aerospace Manufacturing Quality Assurance Standard （BS/EN9100） is one of the most recognised and essential protocols for developing the industry-operated-and-driven quality assurance systems. The research investigates using the ERP based system as an enabler to implement BS/EN9100 quality management system at manufacturing SMEs and the associated implementation and application perspectives. An application case study on a manufacturing SME is presented by using the SAP based implementation, which helps fiarther evaluate and validate the approach and application system development.展开更多
Contact bounce of relay, which is the main cause of electric abrasion and material erosion, is inevitable. By using the mode expansion form, the dynamic behavior of two different reed systems for aerospace relays is a...Contact bounce of relay, which is the main cause of electric abrasion and material erosion, is inevitable. By using the mode expansion form, the dynamic behavior of two different reed systems for aerospace relays is analyzed. The dynamic model uses Euler-Bernoulli beam theory for cantilever beam, in which the driving force (or driving moment) of the electromagnetic system is taken into account, and the contact force between moving contact and stationary contact is simulated by the Kelvin-Voigt vis-coelastic...展开更多
In this study,information on energy usage in the United States(U.S.)aerospace manufacturing sector has been analyzed and then represented as energy intensities(kWh/m2)to establish benchmark data and to compare facilit...In this study,information on energy usage in the United States(U.S.)aerospace manufacturing sector has been analyzed and then represented as energy intensities(kWh/m2)to establish benchmark data and to compare facilities of varying sizes.First,public sources were identified and the data from these previously published sources were aggregated to determine the energy usage of aerospace manufacturing facilities within the U.S.From this dataset,a sample of 28 buildings were selected and the energy intensity for each building was estimated from the data.Next,as a part of this study the energy data for three additional aerospace manufacturing facilities in the U.S.were collected firsthand.That data was analyzed and the energy intensity(kWh/m2)for each facility was calculated and then compared with the energy intensities of the 28 buildings from the sample.Three different indicators of energy consumption in aerospace manufacturing facilities were used as comparators to assist facility managers with determining potential energy savings and help in the decision-making process.On average,aerospace manufacturing facilities in the United States spent 4 cents for each dollar of sale on energy.The energy intensity(kWh/m2)and the power intensity(W/m2)for each facility were calculated based on the actual facility energy bills.The power intensity for these facilities ranges from 34 to 134 W/m2.The energy intensity ranged from 232 to 949 kWh/m2.We found that the power intensity could be used to estimate energy consumption when the annual operating hours of the facility are considered.and to estimate the energy-related carbon dioxide emissions.展开更多
Multi-functional Al-matrix composites with high volume fraction （55%-57%） of SiC particles are produced with the new pressureless infiltration fabrication technology. X-ray detection and microscopic observation disp...Multi-functional Al-matrix composites with high volume fraction （55%-57%） of SiC particles are produced with the new pressureless infiltration fabrication technology. X-ray detection and microscopic observation display the composites which are macroscopically homogeneous without porosity. The investigation further reveals that the SiC/Al composites possess low density （2.94 g/cm^3）, high elastic modulus （220 GPa）, prominent thermal management function as a result of low coefficient of thermal expansion （8 × 10^4 K^-1） and high thermal conductivity （235 W/（m.K）） as well as unique preventability of resonance vibration. By adopting a series of developed techniques, the multi-functional SiC/Al composites have managed to be made into near-net-shape parts. Many kinds of precision components of space-based optomechanical structures and airborne optoelectronic platform have been turned out. Of them, several typical products are being under test in practices.展开更多
With the increasingly excellent performance of magnesium alloy materials, magnesium alloys are increasingly widely used under the urgent need for weight reduction in aerospace applications. However, due to the severe ...With the increasingly excellent performance of magnesium alloy materials, magnesium alloys are increasingly widely used under the urgent need for weight reduction in aerospace applications. However, due to the severe aviation environment, the strength, corrosion resistance and electrical conductivity of magnesium alloy materials need to be further improved. Many scholars are committed to studying higher comprehensive mechanical properties. Besides, they have studied surface treatment processes with space application characteristics, such as high emissivity oxidation and high anti-corrosion electroplating. To further improve the safety and reliability of magnesium alloys and expand their applications, this paper discusses several kinds of magnesium alloys and summarizes their research progress. The whole manuscript should be revised by an expert who has more experience on English writing. At the same time, the surface treatments of magnesium alloy materials for aerospace are analyzed. Besides, the application of magnesium alloy in aerospace field is summarized. With the in-depth research of many scholars, the improvement of material properties and the development of surface protection and functional technology, it is believed that magnesium alloys will be used in more and more aerospace applications and make more contributions to the aerospace field.展开更多
In this paper, the operating conditions, technical requirements, performance characteristics, design ideas, application experiences and development trends of aerospace engine bearings, including material technology, i...In this paper, the operating conditions, technical requirements, performance characteristics, design ideas, application experiences and development trends of aerospace engine bearings, including material technology, integration design and reliability, are reviewed. The development history of aerospace engine bearing is recalled briefly at first. Then today＇s material technologies and the high bearing performances of the bearings obtained through the new materials are introduced, which play important roils in the aeroengine bearing developments. The integration design ideas and practices are explained to indicate its significant advantages and importance to the aerospace engine bearings. And the reliability of the shaft-bearing system is pointed out and treated as the key requirement with goals for both engine and bearing. Finally, as it is believed that the correct design comes from practice, the pre-qualification rig testing conducted by FAG Aerospace GmbH ＆ Co. KG is briefly illustrated as an example. All these lead to the development trends of aerospace engine bearings from different aspects.展开更多
Combination of topology optimization and additive manufacturing technologies provides an effective approach for the development of light-weight and high-performance structures.A heavy-loaded aerospace bracket is desig...Combination of topology optimization and additive manufacturing technologies provides an effective approach for the development of light-weight and high-performance structures.A heavy-loaded aerospace bracket is designed by topology optimization and manufactured by additive manufacturing technology in this work.Considering both mechanical forces and temperature loads,a formulation of thermo-elastic topology optimization is firstly proposed and the sensitivity analysis is derived in detail.Then the procedure of numerical optimization design is presented and the final design is additively manufactured using Selective Laser Melting(SLM).The mass of the aerospace bracket is reduced by over 18%,benefiting from topology and size optimization,and the three constraints are satisfied as well in the final design.This work indicates that the integration of thermo-elastic topology optimization and additive manufacturing technologies can be a rather powerful tool kit for the design of structures under thermal-mechanical loading.展开更多
文摘In the third decade of the 21st century,the aerospace field is evolving at an unprecedented pace towards intelligence and autonomy.As competition for space resource development intensifies,breakthroughs in near-space vehicle technology emerge,and the concept of drone swarm warfare matures,traditional rule-based and experience-driven battlefield situation awareness models are struggling to meet the demands of complex adversarial environments.This special issue brings together the latest research findings from fields such as computer science and technology,electronic engineering,and cognitive science,systematically exploring the cognitive revolution driven by the deep integration of next-generation artificial intelligence and aerospace engineering,all centered around the core theme of"Intelligent Situation Awareness"(ISA).
基金supported by National Natural Science Foundation of China (Grant Nos. 62204104, 42005138, 12274190, 12274189, 62275115)Shandong Province High Education Youth Innovation Team Program (Grant No. 2023KJ210)Science and Technology Program of Yantai (Grant No. 2023JCYJ047)。
文摘Due to advantages of high power-conversion efficiency(PCE), large power-to-weight ratio(PWR), low cost and solution processibility, flexible perovskite solar cells(f-PSCs) have attracted extensive attention in recent years. The PCE of f-PSCs has developed rapidly to over 25%, showing great application prospects in aerospace and wearable electronic devices. This review systematically sorts device structures and compositions of f-PSCs, summarizes various methods to improve its efficiency and stability recent years. In addition, the applications and potentials of f-PSCs in space vehicle and aircraft was discussed. At last, we prospect the key scientific and technological issues that need to be addressed for f-PSCs at current stage.
基金Sponsored by the National Key Research and Development Program from Ministry of Science and Technology of the People's Republic of China (Grant No.2020YFB1711403)。
文摘After the design of aerospace products is completed,a manufacturability assessment needs to be conducted based on 3D model's features in terms of modeling quality and process design,otherwise the cost of design changes will increase.Due to the poor structure and low reusability of product manufacturing feature information and assessment knowledge in the current aerospace product manufacturability assessment process,it is difficult to realize automated manufacturability assessment.To address these issues,a domain ontology model is established for aerospace product manufacturability assessment in this paper.On this basis,a structured representation method of manufacturability assessment knowledge and a knowledge graph data layer construction method are proposed.Based on the semantic information and association information expressed by the knowledge graph,a rule matching method based on subgraph matching is proposed to improve the precision and recall.Finally,applications and experiments based on the software platform verify the effectiveness of the proposed knowledge graph construction and rule matching method.
基金supported by the National Natural Science Foundation of China(U23A20336).
文摘Aerospace optical cables and fiber-optic connectors have numerous advantages(e.g.,low loss,wide transmission frequency band,large capacity,light weight,and excellent resistance to electromagnetic interference).They can achieve optical communication interconnections and high-speed bidirectional data transmission between optical terminals and photodetectors in space,ensuring the stability and reliability of data transmission during spacecraft operations in orbit.They have become essential components in high-speed networking and optically interconnected communications for spacecrafts.Thermal stress simulation analysis is important for evaluating the temperature stress concentration phenomenon resulting from temperature fluctuations,temperature gradients,and other factors in aerospace optical cables and connectors under the combined effects of extreme temperatures and vacuum environments.Considering this,advanced optical communication technology has been widely used in high-speed railway communication networks to transmit safe,stable and reliable signals,as high-speed railway optical communication in special areas with extreme climates,such as cold and high-temperature regions,requires high-reliability optical cables and connectors.Therefore,based on the finite element method,comprehensive comparisons were made between the thermal distributions of aerospace optical cables and J599III fiber optic connectors under different conditions,providing a theoretical basis for evaluating the performance of aerospace optical cables and connectors in space environments and meanwhile building a technical foundation for potential optical communication applications in the field of high-speed railways.
基金supported by the National Natural Science Foundation of China(Nos.52075255,92160301,52175415,52205475,and 92060203)。
文摘The aerospace community widely uses difficult-to-cut materials,such as titanium alloys,high-temperature alloys,metal/ceramic/polymer matrix composites,hard and brittle materials,and geometrically complex components,such as thin-walled structures,microchannels,and complex surfaces.Mechanical machining is the main material removal process for the vast majority of aerospace components.However,many problems exist,including severe and rapid tool wear,low machining efficiency,and poor surface integrity.Nontraditional energy-assisted mechanical machining is a hybrid process that uses nontraditional energies(vibration,laser,electricity,etc)to improve the machinability of local materials and decrease the burden of mechanical machining.This provides a feasible and promising method to improve the material removal rate and surface quality,reduce process forces,and prolong tool life.However,systematic reviews of this technology are lacking with respect to the current research status and development direction.This paper reviews the recent progress in the nontraditional energy-assisted mechanical machining of difficult-to-cut materials and components in the aerospace community.In addition,this paper focuses on the processing principles,material responses under nontraditional energy,resultant forces and temperatures,material removal mechanisms,and applications of these processes,including vibration-,laser-,electric-,magnetic-,chemical-,advanced coolant-,and hybrid nontraditional energy-assisted mechanical machining.Finally,a comprehensive summary of the principles,advantages,and limitations of each hybrid process is provided,and future perspectives on forward design,device development,and sustainability of nontraditional energy-assisted mechanical machining processes are discussed.
基金the support of the National Natural Science Foundation of China(Nos.12372190,12272077)the Fundamental Research Funds for the Central Universities,China(Nos.DUT20RC(5)009,DUT20GJ216).
文摘Good distribution of samples and weights can improve the computational accuracy and efficiency in the stochastic response analyses of aerospace problems with uncertain parameters.This work proposes a new Generalized L2 Discrepancy based on a General Point(GL2D-GP)for generating samples and their corresponding weights.The proposed GL2D-GP is an extension of the existing discrepancy by introducing the non-same weights and a smaller box to measure probability errors.Minimizing the GL2D-GP can yield a weight optimization formula that generates a set of optimal non-identical weights for a given sample set.Through minimizing the GL2D-GP assigned to the set of optimal non-same weights,a new sample and weight generation method is developed.In the proposed method,the samples can be easily generated in terms of the generalized Halton formula with a series of optimal permutation vectors which are found by the intelligent evolutionary algorithm.Once the sample set is obtained,the optimal weights can be generated in terms of the weight optimization formula.Five numerical examples are presented to verify the high accuracy,efficiency,and strong robustness of the proposed sample generation method based on GL2D-GP.
基金co-supported by the Xinjiang Uygur Autonomous Region Natural Science Foundation,China(No.2022D01C86)the National Natural Science Foundation of China(No.62263030)the Open Research Fund Program of Beijing National Research Center for Information Science and Technology,China(No.BR2023KF02011).
文摘A prescribed performance control scheme based on the three-inflection-point hyperbolic function and predefined time performance function is proposed to solve the trajectory tracking problem of the forward-tilting morphing aerospace vehicle with time-varying actuator faults.To accurately estimate the loss degree of actuator faults,an immersion and invariance observer based on the predefined time dynamic scale factor is designed to estimate and compensate it.A composite dynamic sliding mode surface is designed using a three-inflection-point hyperbolic function,and a novel three-inflection-point sliding mode control framework is proposed.The convergent domain of the sliding manifold is adjusted by parameters,and the system error convergence is controllable.A transfer function is designed to eliminate the sensitivity of the three-inflection-point hyperbolic sliding mode to the unknown initial state,and combined with the barrier Lyapunov function,and the performance constraint of the system is realized.The global asymptotic stability of the system is demonstrated using a strict mathematical proof.The effectiveness and superiority of the proposed control scheme are proven by simulation experiments.
基金supported by the National Natural Science Foundation of China(No.51875465)the Shaanxi Province Postdoctoral Research Project Funding,Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(No.CX2023002)+1 种基金the Civil Aircraft Scientific Research Projectthe Fund of Shanghai Engineering Research Center of Civil Aircraft Health Monitoring(No.GCZX-2022-01).
文摘To improve the computational efficiency and accuracy of multi-objective reliability estimation for aerospace engineering structural systems,the Intelligent Vectorial Surrogate Modeling(IVSM)concept is presented by fusing the compact support region,surrogate modeling methods,matrix theory,and Bayesian optimization strategy.In this concept,the compact support region is employed to select effective modeling samples;the surrogate modeling methods are employed to establish a functional relationship between input variables and output responses;the matrix theory is adopted to establish the vector and cell arrays of modeling parameters and synchronously determine multi-objective limit state functions;the Bayesian optimization strategy is utilized to search for the optimal hyperparameters for modeling.Under this concept,the Intelligent Vectorial Neural Network(IVNN)method is proposed based on deep neural network to realize the reliability analysis of multi-objective aerospace engineering structural systems synchronously.The multioutput response function approximation problem and two engineering application cases(i.e.,landing gear brake system temperature and aeroengine turbine blisk multi-failures)are used to verify the applicability of IVNN method.The results indicate that the proposed approach holds advantages in modeling properties and simulation performances.The efforts of this paper can offer a valuable reference for the improvement of multi-objective reliability assessment theory.
文摘Uncertainty Quantification(UQ)is essential in aerospace systems as system performance is high sensitive to uncertainties associated with physics,materials,environments,models,and so forth.While recent advancements in UQ across various engineering fields have introduced new research directions,significant challenges persist in developing methods to address high-dimensional,strongly coupled uncertainties and sparse experimental data.UQ has emerged as an important issue to be addressed in simulation-based aerospacedesign.
文摘Nowadays,the internal structure of spacecraft has been increasingly complex.As its“lifeline”,cables require extensive manpower and resources for manual testing,and it is challenging to quickly and accurately locate quality problems and find solutions.To address this problem,a knowledge graph based method is employed to extract multi-source heterogeneous cable knowledge entities.The method utilizes the bidirectional encoder representations from transformers(BERT)network to embed word vectors into the input text,then extracts the contextual features of the input sequence through the bidirectional long short-term memory(BiLSTM)network,and finally inputs them into the conditional random field(CRF)network to predict entity categories.Simultaneously,by using the entities extracted by this model as the data layer,a knowledge graph based method has been constructed.Compared to other traditional extraction methods,the entity extraction method used in this study demonstrates significant improvements in metrics such as precision,recall and an F1 score.Ultimately,employing cable test data from a particular aerospace precision machining company,the study has constructed the knowledge graph based method in the field to achieve visualized queries and the traceability and localization of quality problems.
文摘目的研究Aerospace Medicine and Human Performance更名前后的主要报道方向、国别、发文机构的变化情况等,以期为国内同行提供参考。方法主要利用CiteSpace的共词网络功能来对期刊报道方向、发刊国别、发文机构等变化进行分析。数据来自Web of Science核心合集的SCI拓展版,以期刊名“Aviation Space and Environmental Medicine”检索,时间跨度为1991年1月1日至2014年12月31日,剔除征稿启事、会议通知等非学术文献。导入NoteExpress软件进行去重,共有4830篇文章。该刊于2015年更名为“Aerospace Medicine and Human Performance”,检索策略为:时间跨度为2015年1月1日至2023年6月13日,数据清洗方法同上,共检索到1076篇文章。结果(1)主要发文机构:更名前主要供稿机构为美国空军(160篇)、美国国防部(93篇)和美国宇航局(NASA,77篇);更名后主要供稿机构未发生变化,但发文数量均较更名前减少,美国空军47篇,美国国防部24篇,NASA 24篇。(2)主要关键词对比:更名后主要关键词与飞行、航天相关的连接强度显著增加,而对一般健康问题的关注相对减少,出现了spaceflight、air travel等直接与飞行行为相关的内容。(3)主要国别:更名前美国发文2411篇(49.91%)、加拿大发文314篇(6.50%)、英国发文279篇(5.77%)、法国发文167篇(3.45%)、德国发文160篇(3.31%);更名后美国发文501篇(46.56%)、英国发文98篇(9.10%)、中国发文54篇(5.01%)、加拿大发文53篇(4.92%)、法国发文42篇(3.90%)。(4)年均发文量:根据检索结果,更名前共24年,年均发文201篇;更名后从2015年至本文检索截止时间共8.5年,年均发文127篇,年均报道量下降较多。(5)影响因子:截止2014年更名前共发文164篇,影响因子1.0051(含自引);2016年是该刊更名有影响因子等统计数据的第一年,共发文132篇,影响因子0.8250;2022年发文109篇,影响因子1.0001(含自引)。综合考量发文量和影响因子,该刊的综合影响力更名后并无显著提升。结论该刊在更名后,对于飞行环境的影响报道有所减少,主要讨论范围从之前的所有飞行类型聚焦为以太空飞行为主,关于飞行行为对人体健康的影响和绩效表现的报道大幅增长,同时也增加了关于飞行装备对飞行安全影响的讨论。随着航空航天技术的进步和航空装备的发展,更深入地探讨航空活动中环境因素对人体长时间复合作用的影响是必然。在该刊更名后,我国的发文数量排名第三,也在一定程度上说明存在高质量原创性成果外流的情况。我国期刊在坚持刊物原有特色的前提下,根据领域研究的发展,与时俱进,探索可持续发展的办刊模式;要进一步明确期刊定位与服务对象,以国家重大需求为导向,聚焦航空航天领域前沿、热点,适时调整栏目设置,提升期刊的学术质量和学科影响力,打造高质量的学术交流平台。
基金National Natural Science Foundation of China (90205011, 60674103)
文摘Future aerospace vehicles （ASV） are designed to fly in both inner and extra atmospheric fields, which requires autonomous adaptability to the uncertainties emanated from abrupt faults and continuously time-varying environments. An autonomous control reconfiguration scheme is presented for ASV to deal with the uncertainties on the base of control effectiveness estimation. The on-line estimation methods for the time-varying control effectiveness of linear control system are investigated. Some sufficient conditions for the estimable system are given for different cases. There are proposed corresponding on-line estimation algorithms which are proved to be convergent and robust to noise using the least-square-based methods. On the ground of fuzzy logic and linear programming, the control allocation algorithms, which are able to implement the autonomous control reconfiguration through the redundant actuators, are put forward. Finally, an integrated system is developed to verify the scheme and algorithms by way of numerical simulation and analysis.
基金Key National Natural Science Foundation of China(50635040)
文摘Thanks to recent advances in manufacturing technology, aerospace system designers have many more options to fabricate high-quality, low-weight, high-capacity, cost-effective filters. Aside from traditional methods such as stamping, drilling and milling, many new approaches have been widely used in filter-manufacturing practices on account of their increased processing abilities. How- ever, the restrictions on costs, the need for studying under stricter conditions such as in aggressive fluids, the complicity in design, the workability of materials, and others have made it difficult to choose a satisfactory method from the newly developed processes, such as, photochemical machining （PCM）, photo electroforming （PEF） and laser beam machining （LBM） to produce small, inexpensive, lightweight aerospace filters. This article appraises the technical and economical viability of PCM, PEF, and LBM to help engineers choose the fittest approach to turn out aerospace filters.
基金support for this research (R85169) from Mollart Engineering Ltd
文摘Aerospace manufacturing SMEs are continuously facing the challenge on managing their supply chain and complying with the aerospace manufacturing quality standard requirement due to their lack of resources and the nature of business. In this paper, the ERP system based approach is presented to quality control and assurance work in light of seamless integration of in-process production data and information internally and therefore managing suppliers more effectively and efficiently. The Aerospace Manufacturing Quality Assurance Standard （BS/EN9100） is one of the most recognised and essential protocols for developing the industry-operated-and-driven quality assurance systems. The research investigates using the ERP based system as an enabler to implement BS/EN9100 quality management system at manufacturing SMEs and the associated implementation and application perspectives. An application case study on a manufacturing SME is presented by using the SAP based implementation, which helps fiarther evaluate and validate the approach and application system development.
文摘Contact bounce of relay, which is the main cause of electric abrasion and material erosion, is inevitable. By using the mode expansion form, the dynamic behavior of two different reed systems for aerospace relays is analyzed. The dynamic model uses Euler-Bernoulli beam theory for cantilever beam, in which the driving force (or driving moment) of the electromagnetic system is taken into account, and the contact force between moving contact and stationary contact is simulated by the Kelvin-Voigt vis-coelastic...
文摘In this study,information on energy usage in the United States(U.S.)aerospace manufacturing sector has been analyzed and then represented as energy intensities(kWh/m2)to establish benchmark data and to compare facilities of varying sizes.First,public sources were identified and the data from these previously published sources were aggregated to determine the energy usage of aerospace manufacturing facilities within the U.S.From this dataset,a sample of 28 buildings were selected and the energy intensity for each building was estimated from the data.Next,as a part of this study the energy data for three additional aerospace manufacturing facilities in the U.S.were collected firsthand.That data was analyzed and the energy intensity(kWh/m2)for each facility was calculated and then compared with the energy intensities of the 28 buildings from the sample.Three different indicators of energy consumption in aerospace manufacturing facilities were used as comparators to assist facility managers with determining potential energy savings and help in the decision-making process.On average,aerospace manufacturing facilities in the United States spent 4 cents for each dollar of sale on energy.The energy intensity(kWh/m2)and the power intensity(W/m2)for each facility were calculated based on the actual facility energy bills.The power intensity for these facilities ranges from 34 to 134 W/m2.The energy intensity ranged from 232 to 949 kWh/m2.We found that the power intensity could be used to estimate energy consumption when the annual operating hours of the facility are considered.and to estimate the energy-related carbon dioxide emissions.
基金Foundation items： High-technology Research and Development Programme of China （2007AA03Z544） Aeronautical Science Foundation of China （20075221001）
文摘Multi-functional Al-matrix composites with high volume fraction （55%-57%） of SiC particles are produced with the new pressureless infiltration fabrication technology. X-ray detection and microscopic observation display the composites which are macroscopically homogeneous without porosity. The investigation further reveals that the SiC/Al composites possess low density （2.94 g/cm^3）, high elastic modulus （220 GPa）, prominent thermal management function as a result of low coefficient of thermal expansion （8 × 10^4 K^-1） and high thermal conductivity （235 W/（m.K）） as well as unique preventability of resonance vibration. By adopting a series of developed techniques, the multi-functional SiC/Al composites have managed to be made into near-net-shape parts. Many kinds of precision components of space-based optomechanical structures and airborne optoelectronic platform have been turned out. Of them, several typical products are being under test in practices.
文摘With the increasingly excellent performance of magnesium alloy materials, magnesium alloys are increasingly widely used under the urgent need for weight reduction in aerospace applications. However, due to the severe aviation environment, the strength, corrosion resistance and electrical conductivity of magnesium alloy materials need to be further improved. Many scholars are committed to studying higher comprehensive mechanical properties. Besides, they have studied surface treatment processes with space application characteristics, such as high emissivity oxidation and high anti-corrosion electroplating. To further improve the safety and reliability of magnesium alloys and expand their applications, this paper discusses several kinds of magnesium alloys and summarizes their research progress. The whole manuscript should be revised by an expert who has more experience on English writing. At the same time, the surface treatments of magnesium alloy materials for aerospace are analyzed. Besides, the application of magnesium alloy in aerospace field is summarized. With the in-depth research of many scholars, the improvement of material properties and the development of surface protection and functional technology, it is believed that magnesium alloys will be used in more and more aerospace applications and make more contributions to the aerospace field.
文摘In this paper, the operating conditions, technical requirements, performance characteristics, design ideas, application experiences and development trends of aerospace engine bearings, including material technology, integration design and reliability, are reviewed. The development history of aerospace engine bearing is recalled briefly at first. Then today＇s material technologies and the high bearing performances of the bearings obtained through the new materials are introduced, which play important roils in the aeroengine bearing developments. The integration design ideas and practices are explained to indicate its significant advantages and importance to the aerospace engine bearings. And the reliability of the shaft-bearing system is pointed out and treated as the key requirement with goals for both engine and bearing. Finally, as it is believed that the correct design comes from practice, the pre-qualification rig testing conducted by FAG Aerospace GmbH ＆ Co. KG is briefly illustrated as an example. All these lead to the development trends of aerospace engine bearings from different aspects.
基金supported by the National Key Research and Development Program of China(Nos.2017YFB1102800,2016YFB0201600)the National Natural Science Foundation of China(Nos.11672239,51735005)。
文摘Combination of topology optimization and additive manufacturing technologies provides an effective approach for the development of light-weight and high-performance structures.A heavy-loaded aerospace bracket is designed by topology optimization and manufactured by additive manufacturing technology in this work.Considering both mechanical forces and temperature loads,a formulation of thermo-elastic topology optimization is firstly proposed and the sensitivity analysis is derived in detail.Then the procedure of numerical optimization design is presented and the final design is additively manufactured using Selective Laser Melting(SLM).The mass of the aerospace bracket is reduced by over 18%,benefiting from topology and size optimization,and the three constraints are satisfied as well in the final design.This work indicates that the integration of thermo-elastic topology optimization and additive manufacturing technologies can be a rather powerful tool kit for the design of structures under thermal-mechanical loading.
