检索结果-南通市图书馆

Journal of mater.als Science & Technology 2001年第1期17卷 65-66页

作者： Weifang ZHANG Niansheng XI and Chunhu TAO inst.tute of aeronaut.cal mater.als, Beijing 100095, China Jiecai HAN and Shanyi DU Center for Composite mater.als, Harbin inst.tute of Technology, Harbin 150001, China inst. of aeronaut. mater. Beijing 100095 China

The microstructure and composition of TiC-A12O3/Fe functionally graded mater.als (FGM) prepared by self-propagating high temperature synthesis and pseudo-hot isostatic pressing (SHS/ PHIP) were studied, and the resisting thermal shock behaviors were analyzed. The results show that TiC-A12O3/Fe FGM has graded composition distribution. No cross-section crack through the layers was found in the tests of thermal shock and fatigue.

关键词： functionally graded mater.als thermal shock graded composition high temperature

Microstructure Characteristic of In-situ Ti/TiC Composites

在线全文

学校读者我要写书评

暂无评论

Journal of mater.als Science & Technology 2001年第1期17卷 103-104页

作者： Bo YANG Beijing inst.tute of aeronaut.cul mater.als, Beijing 100095, China Erlin ZHANG Yunxue JIN Zhaojun ZHU and Songyan ZENG National Key Lab. of Precision Hot Processing of Metals, Harbin inst.tute of Technology, Harbin 150001, China inst. of aeronaut. mater. Beijing 100095 China

TiC reinforced titanium composites has been produced with different Al content and C content by XDTM. The results have shown that TiC particles are of two different morphologies f coarse dendritical primary TiC and short bar-shape eutectic TiC. Al content has great effects on the morphology of TiC. With the increasing of Al content, the morphology of primary TiC changes from coarse developed dendrite into short bar-shape or plate--shape TiC with 35%Al. Meanwhile, the structure of the matrix changes from single Ti to Ti and Ti3Al, and to Ti3Al and TiAl. However, the C content has no influence on the microstructure of matrix. When the C content is less than 1.2%, the dendrite TiC disappears and only short bar-shape or plate-shape TiC exists in the composites. In addition, the effect of he3t treatment on the morphology of TiC has also Studied.

关键词： TiC Microstructure Characteristic of In-situ Ti/TiC Composites

Toughness and Hot/Wet Properties of a Novel Modified BMI/Carbon Fiber Composite

在线全文

学校读者我要写书评

暂无评论

Journal of mater.als Science & Technology 2001年第1期17卷 17-18页

作者： Zhang B.Y. Chen X.B. Li P. Yi X.S. Beijing inst. of aeronaut. mater. Beijing 100095 China

The toughness and hot/wet properties of a novel modified bismaleimide (BMI) 5428/carbon fiber composite were investigated. Results indicate that the prepared BMI/T700 composite has high toughness, excellent hot/wet properties and mechanical properties. The compression strength of the 5428/T700 composite after impact (CAl) is 260 MPa, and the hot/wet test results show that the long-term service temperature of 5428/T700 composite can maintain at 170°C.

关键词： BMI Toughness and Hot/Wet Properties of a Novel Modified BMI/Carbon Fiber Composite

An optimized time-adaptive aerothermal coupling calculation method for aerothermal analysis of disc cavity system

在线全文

学校读者我要写书评

暂无评论

CHINESE JOURNAL OF aeronaut.CS 2024年第9期37卷 164-177页

作者： Bi, Shuai Mao, Junkui Wang, Lei Han, Feng Nanjing Univ aeronaut.& Astronaut Coll Energy & Power Engn Nanjing 210016 Peoples R China Nanjing Univ aeronaut.& Astronaut Integrated Energy Inst Nanjing 210016 Peoples R China AECC Aeroengine Control Syst inst Wuxi 214063 Peoples R China

In order to further achieve the balance between the calculation accuracy and efficiency of the transient analysis of the aero-engine disc cavity system, an Optimized Time-adaptive Aerothermal Coupling calculation (OTAC) method has been proposed. It combines one-dimensional transient calculation of air system, Conventional Sequence Staggered (CSS) method, Time-adaptive Aerothermal Coupling calculation (TAC) method and differential evolution optimization algorithm to obtain an efficient and high-precision aerothermal coupling calculation method of air system. Considering both the heat conduction in the solid domain and the flow in the fluid domain as unsteady states in the OTAC, the interaction of fluid-solid information within a single coupling time step size was implemented based on the CSS method. Furthermore, the coupling time step size was automatically adjusted with the number of iterations by using the Proportional-Integral-Deri vative (PID) controller. Results show that when compared with the traditional loosely coupling method with a fixed time step size, the computational accuracy and efficiency of the OTAC method are improved by 8.9% and 30%, respectively. Compared with the tight coupling calculation, the OTAC method can achieve a speedup of 1 to 2 orders of magnitude, while the calculation error is maintained within 6.1%. (c) 2024 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of aeronaut.cs and Astronautics This is an open access article under the CC BY-NC-ND license (http://***/ licenses/by-nc-nd/4.0/).

关键词： Air system 1D-3D coupling Conjugate heat transfer Transient calculation Adaptive time step size

Identification of aircraft longitudinal aerodynamic parameters using an online corrective test for wind tunnel virtual flight

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CHINESE JOURNAL OF aeronaut.CS 2024年第9期37卷 261-275页

作者： Tai, Shang Bu, Chen Wang, Yanling Yue, Ting Liu, Hailiang Wang, Lixin Beihang Univ Sch Aeronaut Sci & Engn Beijing 100191 Peoples R China AVIC Aerodynam Res inst Harbin 150001 Peoples R China

The identification of aerodynamic parameters is accomplished through the test data of the dynamic movement of scaled aircraft models flying dynamically in wind tunnel, which can realize the accurate acquisition of the aerodynamic model of the aircraft in the preliminary stage for aircraft design, and it is of great significance for improving the efficiency of aircraft design. However, the translational motion of the test model in the wind tunnel virtual flight is subject to constraints that result in distinct flight dynamics compared to free flight. These constraints have implications for the accuracy of aerodynamic derivatives obtained through the identification of wind tunnel test data. With this issue in mind, the research studies the differences in longitudinal dynamic characteristics between unconstrained free flight and wind tunnel virtual flight, and innovatively proposes an online correction test based wind tunnel virtual flight test technique. The longitudinal trajectory and velocity changes of the model are solved online by the aerodynamic forces measured during the test, and then the coupled relationship between aircraft translation and rotation is used to correct the model's pitch attitude motion online. For the first time, the problem of solving the data approximation for free flight has been solved, eliminating the difference between the dynamics of wind tunnel virtual flight and free flight, and improving the accuracy of the aerodynamic derivative identification results. The experiment's findings show that accurate aerodynamic derivatives can be identified based on the online correction test data, and the observed behaviour of the identified motion model has similarities to that of the free flight motion model. (c) 2024 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of aeronaut.cs and Astronautics. This is an open access article under the CC BY-NC-ND license (http://***/ licenses/by-nc-nd/4.0/).

关键词： Wind tunnels Displacement constraints Online solution Flight control law Aerodynamic parameter identification MODEL SIMULATION STABILITY MANEUVER DESIGN RIG

Inverse aerodynamic design for distributed propulsion wing with expected circulation distribution

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CHINESE JOURNAL OF aeronaut.CS 2024年第9期37卷 206-223页

作者： Sun, Pengbo Zhou, Zhou Li, Xu Wang, Kelei Northwestern Polytech Univ Sch Aeronaut Xian 710072 Peoples R China

Distributed Propulsion Wing (DPW) technology offers significant advantages in terms of flight energy savings, but the strong aerodynamic coupling between the propulsive internal flow and aerodynamic external flow brings significant design challenges. As the primary DPW profile design is of great significance, this paper proposes a hybrid method to solve the inverse problem mainly based on the formula relationship between the required aerodynamic loads and the profile shape, which is more direct and inst.uctive compared with traditional parametric iterative methods. The aerodynamic characteristics are described by the circulation distribution in the Fourier series form, then the mean camber line of the profile is solved through the re-derived airfoil theory considering disk's influence. Further CFD correction methods are also proposed. To validate the effectiveness and feasibility of the proposed hybrid inverse method, several DPW profile design tests are then conducted. Finally, the relationship between 2D and realistic 3D unit shape is also researched. The results show that the proposed inverse design method has great accuracy and convergence speed in the design tests, and shows good robustness against.changes of the design parameters. The 2D profile shape and the actual 3D shape of DPW unit can establish an aerodynamicpropulsion equivalent relationship based on the same internal mass fluxes. (c) 2024 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of aeronaut.cs and Astronautics. This is an open access article under the CC BY-NC-ND license (http://***/ licenses/by-nc-nd/4.0/).

关键词： Inverse problem Aerodynamic load Fourier series Flux FLOW SIMULATION SHAPE DESIGN HYBRID OPTIMIZATION

Preparation of Silicon Carbide with High Properties

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of mater.als Science & Technology 2001年第1期17卷 53-54页

作者： Guangiiang YUAN Yang ZHOU and Daming CHEN National Key Laboratory of Advanced Composites, Beijing inst.tute of aeronaut.cal mater.als, P.O. Box 81-3, Beijing 100095, China Bangsheng LI School of mater.als Science and Engineering, Harbin inst.tute of Tech Natl. Key Lab. of Adv. Composites Beijing Inst. of Aeronaut. Mater. P.O. Box 81-3 Beijing 100095 China

In order to prepare silicon carbide with high properties, three kinds of SiC powders A, B, and C with different composition and two kinds of additives, which were Y2O3-A12O3 system and Y2O3-La2O3 system, were used in this experiment. The properties of hot-pressed SiC ceramics were measured. With the same additives, different SiC powder resulted in different properties. On the other hand, with the same SiC powder, increasing the amount of the additive Y2O3Al2O3 improved properties of SiC ceramics at room temperature, and increasing the amount of the additive Y2O3-La2O3 improved property SiC ceramics at elevated temperature. In addition. the microstructure of SiC ceramics was studied by scanning electron microscopy.

关键词： SiC Preparation of Silicon Carbide with High Properties

Nonlinear aeroelastic analysis of a twin-tail boom UAV with rudder freeplay nonlinearities

在线全文

学校读者我要写书评

暂无评论

CHINESE JOURNAL OF aeronaut.CS 2024年第9期37卷 276-296页

作者： Bai, Liuyue Wu, Zhigang Yang, Chao Beihang Univ Sch Aeronaut Sci & Engn Beijing 100191 Peoples R China

The issue of nonlinear structural freeplays in aircraft has always been a significant concern. This study investigates the aeroelastic characteristics of a twin-tail boom Unmanned Aerial Vehicle (UAV) with simultaneous freeplay nonlinearity in its left and right rudders. A comprehensive Limit Cycle Oscillation (LCO) solution route is proposed for complex aircraft with multiple freeplays, which can consider both accuracy and efficiency. For the first time, this study reveals the unique LCO characteristics exhibited by twin-tail boom UAVs with rudder freeplays and provides simulations and explanations of interesting phenomena observed during actual flight. The governing equations are established using the free-interface component mode synthesis method, and the LCOs of the system are mainly solved through the improved time-domain numerical continuation method and frequency-domain numerical continuation method. Furthermore, the study investigates the influence of the left and right rudder freeplay size ratio on the LCO characteristics. The results demonstrate that the twin-tail boom UAV exhibits two stable LCO types: close and differing left and right rudder amplitudes. The proposed method successfully describes the complete LCO behaviors of the system. Overall, this study makes significant contributions to our understanding of the aeroelastic behavior of twin-tail boom UAVs with rudder freeplays. (c) 2024 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of aeronaut.cs and Astronautics. This is an open access article under the CC BY-NC-ND license (http://***/ licenses/by-nc-nd/4.0/).

关键词： Aeroelasticity Freeplay nonlinearity Limit cycle oscillation Numerical continuation Component mode synthesis LIMIT-CYCLE OSCILLATION STRUCTURAL NONLINEARITIES CONTROL SURFACE BIFURCATION-ANALYSIS DYNAMIC-ANALYSIS FLUTTER AIRFOIL INTEGRATION SYSTEMS CONTINUATION

Predicting the evolution of electrochemical trepanning for inner blisks with a chamfer structure at blade tip

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CHINESE JOURNAL OF aeronaut.CS 2024年第9期37卷 560-576页

作者： Jiao, Erhao Zhu, Dong Wang, Penghui Zuo, Hang Chen, Liyong Nanjing Univ aeronaut.& Astronaut Coll Mech & Elect Engn Nanjing 210016 Peoples R China

Electrochemical trepanning (ECTr) is an effective electrochemical machining (ECM) technique that can be used to manufacture the integral components of aero-engine compressors. This study focused on the dynamic evolution of ECTr for production of inner blisks (bladed disks) with a special chamfer structure at blade tip. Due to the existence of chamfer, the ECTr process of inner blades is in a non-equilibrium state during the early stages, and the physical field changes in the machining gap are complex, making it difficult to predict the forming process. In this paper, a dynamic evolution model (DEM) of inner blade ECTr with a special chamfer at blade tip structure is proposed, and an ECTr multi-physical fields simulation study was carried out. The evolution of the chamfer at blade tip was analyzed and data related to chamfer were predicted based on the dependence of anode boundary properties with machining time and feed rate. In addition, the distributions of current density, electrolyte flow rate, bubble volume fraction, temperature rise, and electrolyte conductivity in the machining area at different times were obtained by combining them with the multi-physical fields simulation results. Subsequently, a series of ECTr experiments were conducted, in which, as the feed rate increased, the surface quality and machining accuracy of the inner blades were improved. Compared with the simulation results, the error in machining accuracy of the chamfer profile is controlled within +/- 2%, and the machining accuracy of the blade full profile was controlled within +/- 0.2 mm, indicating that the model proposed in this study was effective in predicting the evolution of inner blades ECTr with chamfer structures at blade tip. (c) 2024 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of aeronaut.cs and Astronautics This is an open access article under the CC BY-NC-ND license (http://***/ licenses/by-nc-nd/4.0/).

关键词： Chamfer structure Inner blisk Electrochemical trepanning (ECTr) Dynamic evolution model Forming prediction Multiphysics Machining quality mater.AL REMOVAL PROCESS CONVEX STRUCTURE SIMULATION MANUFACTURE PART

Superplasticity of a Ti-24Al-14Nb-3V-0.5Mo Intermetallic Alloy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of mater.als Science & Technology 2001年第1期17卷 119-120页

作者： Hanliang ZHU Zhiqiang LI Bosheng SHANG Wenfeng MAO and Chunxiao WANG Beijing aeronaut.cal Manufacturing Technology Research inst.tute, Beijing 100024, China Shiqiong LI and Jianwei ZHANG Central iron and Steel Research inst.tute, Beijing 100081, China aeronaut. Manuf. Technol. Res. inst. Beijing 100024 China

Superplastic properties and microstructural evolution of a Ti-24Al-14Nb-3V-0.5Mo (at. pct) intermetallic alloy were studied. Optimum superplastic properties were obtained for temperatures in the interval 960℃≤5 T≤5980℃. The apparent activation energy in the superplastic regime was determined and the deformation mechanism was also discussed. Based on the studies, a curve panel with three sheets sandwich structure was fabricated successfully. The microstructures corresponding to different strain in the part were also studied.

关键词： Al Ti Mo Superplasticity of a Ti-24Al-14Nb-3V-0.5Mo Intermetallic Alloy