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| 1 | Nonlinear Aeroelastic Response of High-aspect-ratio Flexible Wings显示文摘The aeroelastic analysis of high-altitude,long-endurance(HALE) aircraft that features high-aspect-ratio flexible wings needs take into account structural geometrical nonlinearities and dynamic stall.For a generic nonlinear aeroelastic system,besides the stability boundary,the characteristics of the limit-cycle oscillation(LCO) should also be accurately predicted.In order to conduct nonlinear aeroelastic analysis of high-aspect-ratio flexible wings,a first-order,state-space model is developed by combining a geometrically exact,nonlinear anisotropic beam model with nonlinear ONERA(Edlin) dynamic stall model.The present inves-tigations focus on the initiation and sustaining mechanism of the LCO and the effects of flight speed and drag on aeroelastic behaviors.Numerical results indicate that structural geometrical nonlinearities could lead to the LCO without stall occurring.As flight speed increases,dynamic stall becomes dominant and the LCO increasingly complicated.Drag could be negligible for LCO type,but should be considered to exactly predict the onset speed of flutter or LCO of high-aspect-ratio flexible wings. | Zhang Jian,Xiang Jinwu School of Aeronautic Science and Engineering,Beijing University of Aeronautics and Astronautics,Beijing 100191,China | 2009 | Chinese Journal of Aeronautics2009，22，4： | 14 |
| 2 | Flight safety measurements of UAVs in congested airspace显示文摘Describing spatial safety status is crucial for high-density air traffic involving multiple unmanned aerial vehicles(UAVs) in a complex environment. A probabilistic approach is proposed to measure safety situation in congested airspace. The occupancy distribution of the airspace is represented with conflict probability between spatial positions and UAV. The concept of a safety envelope related to flight performance and response time is presented first instead of the conventional fixed-size protected zones around aircraft. Consequently, the conflict probability is performance-dependent, and effects of various UAVs on safety can be distinguished. The uncertainty of a UAV future position is explicitly accounted for as Brownian motion. An analytic approximate algorithm for the conflict probability is developed to decrease the computational consumption. The relationship between safety and flight performance are discussed for different response times and prediction intervals. To illustrate the applications of the approach, an experiment of three UAVs in formation flight is performed. In addition, an example of trajectory planning is simulated for one UAV flying over airspace where five UAVs exist. The validation of the approach shows its potential in guaranteeing flight safety in highly dynamic environment. | Xiang Jinwu Liu Yang Luo Zhangping | 2016 | Chinese Journal of Aeronautics2016，29，5： | 14 |
| 3 | Recent advance in nonlinear aeroelastic analysis and control of the aircraft显示文摘A review on the recent advance in nonlinear aeroelasticity of the aircraft is presented in this paper. The nonlinear aeroelastic problems are divided into three types based on different research objects,namely the two dimensional airfoil,the wing,and the full aircraft. Different nonlinearities encountered in aeroelastic systems are discussed firstly,where the emphases is placed on new nonlinear model to describe tested nonlinear relationship. Research techniques,especially new theoretical methods and aeroelastic flutter control methods are investigated in detail. The route to chaos and the cause of chaotic motion of two-dimensional aeroelastic system are summarized. Various structural modeling methods for the high-aspect-ratio wing with geometric nonlinearity are discussed. Accordingly,aerodynamic modeling approaches have been developed for the aeroelastic modeling of nonlinear high-aspect-ratio wings. Nonlinear aeroelasticity about high-altitude longendurance(HALE) and fight aircrafts are studied separately. Finally,conclusions and the challenges of the development in nonlinear aeroelasticity are concluded. Nonlinear aeroelastic problems of morphing wing,energy harvesting,and flapping aircrafts are proposed as new directions in the future. | Xiang Jinwu Yan Yongju Li Daochun | 2014 | Chinese Journal of Aeronautics2014，27，1： | 14 |
| 4 | Aeroservoelastic modeling and analysis of a canard-configured air-breathing hypersonic vehicles显示文摘Air-breathing hypersonic vehicles (HSVs) are typically characterized by interactions of elasticity, propulsion and rigid-body flight dynamics, which may result in intractable aeroservoelastic problem. When canard is added, this problem would be even intensified by the introduction of low-frequency canard pivot mode. This paper concerns how the aeroservoelastic stability of a canard-configured HSV is affected by the pivot stiffnesses of all-moveable horizontal tail (HT) and canard. A wing/pivot system model is developed by considering the pivot torsional flexibility, fuselage vibration, and control input. The governing equations of the aeroservoelastic system are established by combining the equations of rigid-body motion, elastic fuselage model, wing/pivot system models and actuator dynamics. An unsteady aerodynamic model is developed by steady Shock-Expansion theory with an unsteady correction using local piston theory. A baseline controller is given to provide approximate inflight characteristics of rigid-body modes. The vehicle is trimmed for equilibrium state, around which the linearized equations are derived for stability analysis. A comparative study of damping ratios, closed-loop poles and responses are conducted with varying controller gains and pivot stiffnesses. Available bandwidth for control design is discussed and feasible region for pivot stiffnesses of HT and canard is given. | Zeng Kaichun Xiang Jinwu Li Daochun | 2013 | Chinese Journal of Aeronautics2013，26，4： | 7 |
| 5 | Aerodynamic Performance of the Locust Wing in Gliding Mode at Low Reynolds Number显示文摘 | Jinwu Xiang Jianxun Du Daochun Li Kai Liu | 2016 | Journal of Bionic Engineering2016，13，2： | 6 |
| 6 | Identification of differentially expressed genes in rat silicosis model by suppression subtractive hybridization analysis显示文摘在肺的纤维变性的发展的批评分子的机制仍然保持未知,让有差的预后的病人诊断。孤立在肺的纤维变性明确地起来调整的基因,我们建立了一个老鼠矽肺模型在有水晶的硅石暂停的治疗以后的 360 d。胸的拍证明一些散布高密度的阴影出现在肺地里。典型显微镜的小谎 rosing silicotic 小瘤在肺,牙槽的上皮的房间和支气管的上皮的房间形成了,特别地在部分 fibrosing silicotic 小瘤附近;他们中的一些显示出建议了在矽肺和肺癌症之间的关联的不正常的增生。抑制减少性的杂交分析被执行在肺织物把基因表示与矽肺和正常的肺织物作比较。反向的抄写聚合酶链反应证明七个新奇 cDNA 序列的表情由在有矽肺的肺织物的减少性的杂交不同于的抑制识别了正常的肺织物。生物信息学分析证明 47 积极克隆代表了包含二通常认为的蛋白质的 35 基因,四预言了类似的蛋白质。分析也证明一些在矽肺屏蔽了基因,例如 prolyl 4-hydroxylases,肌动朊相关的 protein-2/3 建筑群和酸的哺乳动物的 chitinase,以前没被报导。这些基因可以为在肺的纤维变性的发展调查分子的机制提供新线索。 | Zhongyuan Jin Baoan Liu Deyun Feng Chen Chen Xiang Li Yongbin Hu Jinwu Peng Yu Liu Jing Du Chunyan Fu Jifang Wen | 2008 | Acta Biochimica et Biophysica Sinica2008，40，8： | 6 |
| 7 | Multi-objective robust airfoil optimization based on non-uniform rational B-spline (NURBS) representation显示文摘In order to improve airfoil performance under different flight conditions and to make the performance insensitive to off-design condition at the same time,a multi-objective optimization approach considering robust design has been developed and applied to airfoil design. Non-uniform rational B-spline (NURBS) representation is adopted in airfoil design process,control points and related weights around airfoil are used as design variables. Two airfoil representation cases show that the NURBS method can get airfoil geometry with max geometry error less than 0.0019. By using six-sigma robust approach in multi-objective airfoil design,each sub-objective function of the problem has robustness property. By adopting multi-objective genetic algorithm that is based on non-dominated sorting,a set of non-dominated airfoil solutions with robustness can be obtained in the design. The optimum robust airfoil can be traded off and selected in these non-dominated solutions by design tendency. By using the above methods,a multi-objective robust optimization was conducted for NASA SC0712 airfoil. After performing robust airfoil optimization,the mean value of drag coefficient at Ma0.7-0.8 and the mean value of lift coefficient at post stall regime (Ma0.3) have been improved by 12.2% and 25.4%. By comparing the aerodynamic force coefficients of optimization result,it shows that: different from single robust airfoil design which just improves the property of drag divergence at Ma0.7-0.8,multi-objective robust design can improve both the drag divergence property at Ma0.7-0.8 and stall property at low speed. The design cases show that the multi-objective robust design method makes the airfoil performance robust under different off-design conditions. | LIANG Yu, CHENG XiaoQuan, LI ZhengNeng & XIANG JinWu School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China | 2010 | Science China(Technological Sciences)2010，53，10： | 4 |
| 8 | Design and experimental study of a new flapping wing rotor micro aerial vehicle显示文摘A three-wing Flapping Wing Rotor Micro Aerial Vehicle(FWR-MAV)which can perform controlled flight is introduced and an experimental study on this vehicle is presented.A mechanically driven flapping rotary mechanism is designed to drive the three flapping wings and generate lift,and control mechanisms are designed to control the pose of the FWR-MAV.A flight control board for attitude control with robust onboard attitude estimation and a control algorithm is also developed to perform stable hovering flight and forward flight.A series of flight tests was conducted,with hovering flight and forward flight tests performed to optimize the control parameters and assess the performance of the FWR-MAV.The hovering flight test shows the ability of the FWR-MAV to counteract the moment generated by rotary motion and maintain the attitude of the FWR-MAV in space;the experiment of forward flight shows that the FWR-MAV can track the desired attitude. | Xin DONG Daochun LI Jinwu XIANG Ziyu WANG | 2020 | Chinese Journal of Aeronautics2020，33，12： | 3 |
| 9 | Crashworthiness uncertainty analysis of typical civil aircraft based on Box–Behnken method显示文摘The crashworthiness is an important design factor of civil aircraft related with the safety of occupant during impact accident. It is a highly nonlinear transient dynamic problem and may be greatly influenced by the uncertainty factors. Crashworthiness uncertainty analysis is conducted to investigate the effects of initial conditions, structural dimensions and material properties. Simplified finite element model is built based on the geometrical model and basic physics phenomenon. Box–Behnken sampling and response surface methods are adopted to obtain gradient information.Results show that the proposed methods are effective for crashworthiness uncertainty analysis.Yield stress, frame thickness, impact velocity and angle have great influence on the failure behavior,and yield stress and frame thickness dominate the uncertainty of internal energy. Failure strain and tangent modulus have the smallest influence on the initial peak acceleration, and gradients of mean acceleration increase because the appearance of material plastic deformation and element failure. | Ren Yiru Xiang Jinwu | 2014 | Chinese Journal of Aeronautics2014，27，3： | 3 |
| 10 | A modified airfoil-based piezoaeroelastic energy harvester with double plunge degrees of freedom显示文摘In this letter,a piezoaeroelastic energy harvester based on an airfoil with double plunge degrees of freedom is proposed to additionally take advantage of the vibrational energy of the airfoil pitch motion.An analytical model of the proposed energy harvesting system is built and compared with an equivalent model using the well-explored pitch-plunge configuration.The dynamic response and average power output of the harvester are numerically studied as the flow velocity exceeds the cut-in speed(flutter speed).It is found that the harvester with double-plunge configuration generates 4%–10% more power with varying flow velocities while reducing 6% of the cut-in speed than its counterpart. | Yining Wu Daochun Li Jinwu Xiang Andrea Da Ronch | 2016 | Theoretical & Applied Mechanics Letters2016，6，5： | 2 |
| 11 | A novel trajectory planning strategy for aircraft emergency landing using Gauss pseudospectral method显示文摘To improve the survivability during an emergency situation, an algorithm for aircraft forced landing trajectory planning is proposed. The method integrates damaged aircraft modelling and trajectory planning into an optimal control framework. In order to deal with the complex aircraft flight dynamics, a solving strategy based on Gauss pseudospetral method(GPM) is presented.A 3-DOF nonlinear mass-point model taking into account the wind is developed to approximate the aircraft flight dynamics after loss of thrust. The solution minimizes the forced landing duration, with respect to the constraints that translate the changed dynamics, flight envelope limitation and operational safety requirements. The GPM is used to convert the trajectory planning problem to a nonlinear programming problem(NLP), which is solved by sequential quadratic programming algorithm. Simulation results show that the proposed algorithm can generate the minimum-time forced landing trajectory in event of engine-out with high efficiency and precision. | Shaohua MENG Jinwu XIANG Zhangping LUO Yiru REN Nanjian ZHUANG | 2014 | Control Theory and Technology2014，12，4： | 2 |
| 12 | Aerodynamic characteristics of morphing wing withflexible leading-edge显示文摘The morphing wing can improve the flight performance during different phases.However,research has been subject to limitations in aerodynamic characteristics of the morphing wing with a flexible leading-edge.The computational fluid dynamic method and dynamic mesh were used to simulate the continuous morphing of the flexible leading-edge.After comparing the steady aerodynamic characteristics of morphing and conventional wings,this study examined the unsteady aerodynamic characteristics of morphing wings with upward and downward deflections of the leading-edge at different frequencies.The numerical results show that for the steady aerodynamic,the leading-edge deflection mainly affects the stall characteristic.The downward deflection of the leading-edge increases the stall angle of attack and nose-down pitching moment.The results are opposite for the upward deflection.For the unsteady aerodynamic,at a small angle of attack,the transient lift coefficient of the upward deflection,growing with the increase of deflection frequency,is larger than that of the static case.The transient lift coefficient of the downward deflection,decreasing with the increase of deflection frequency,is smaller than that of the static case.However,at a large angle of attack,an opposite effect of deflection frequency on the transient lift coefficient was demonstrated.The transient lift coefficient is larger than that of the static case when the leading edge is in the nose-up stage,and lower than that of the static one in the nose-down stage. | Zi KAN Daochun LI Tong SHEN Jinwu XIANG Lu ZHANG | 2020 | Chinese Journal of Aeronautics2020，33，10： | 1 |
| 13 | Design and experiment of spray and rotary tillage combined disinfection machine for soil显示文摘A spray and rotary tillage combined disinfection machine for soil was designed to solve the serious problems of plant diseases and insect pests,and it was divided into two operations which were soil disinfection and rotary tillage.The main structure and working principle of this machine were illustrated and analyzed.The reasonable structural parameters of the key parts of this machine were optimized,such as spraying disinfection system and rotary tillage land preparation system.To optimize the working performance and obtain better operation parameters,the orthogonal experiments were carried out to analyze the influences of three factors(forward speed of driving machine,rotational speed of rotary tillage,and working pressure)on the working performance.The mixing uniformity coefficient and the variation coefficient of spraying were selected for evaluating working performance.The range analysis and variance analysis were studied based on experimental data.The results showed that,the mixing uniformity coefficient of spraying was 93.95%and the variation coefficient was 6.01%with a working speed of 3 km/h,rotational speed of 2000 r/min and working pressure of 2.0 MPa.The machine can meet the agronomic requirements of disinfection and plowing,which was designed simply,compactly and strong applicability.The results can provide a guidance and technical support for preventing the plant diseases and insect pests,developing sustainable and ecological agriculture and improving the efficiency of compound cultivation. | Jinwu Wang Wenpan Yang Xiaobo Sun Xiang Li Han Tang | 2019 | International Journal of Agricultural and Biological Engineering2019，12，1： | 1 |
| 14 | Design,Modeling and Analysis of a Sharp-edge Hypersonic Stealthy Re-entry Vehicle显示文摘 | Liu Guofu Li Daochun Xiang Jinwu | 2015 | Procedia Engineering2015，99，： | 1 |
| 15 | Role of Extracellular Signal-Regulated Kinase, p38 Kinase, and Activator Protein-1 in Transforming Growth Factor-β1–Induced Alpha Smooth Muscle Actin Expression in Human Fetal Lung Fibroblasts In Vitro显示文摘 | Yongbin Hu Jinwu Peng Deyun Feng Ling Chu Xiang Li Zhongyuan Jin Zhi Lin Qingfu Zeng | 2006 | Lung2006，，1： | 1 |
| 16 | Aeroelasticdynamic response and control of an airfoil section withcontrol surface nonlinearities显示文摘 | Li Daochun Guo Shijun Xiang Jinwu | 2010 | Journal of Sound andVibration2010，329，： | 1 |
| 17 | Composite rotor blade design optimization for vibration rduetion with aeroelastie constraints 显示文摘 | Guo Junxian Xiang Jinwu | 2004 | Journal of Aeronautics2004，17，3： | 1 |
| 18 | A comparative study of the crashworthiness of civil aircraft with different strut configurations 显示文摘 | REN YiRu XIANG JinWu | 2010 | International Journal of Crashworthiness2010，15，3： | 1 |
| 19 | Composite rotor blade design optimization for vibration reduction with aeroelastie constraints chinese显示文摘 | Guo Junxian Xiang Jinwu | 2004 | Journal of Aeronautics2004，17，3： | 1 |
| 20 | Composite Rotor Blade Design Optimization for Vibration Rduetion with Aeroelastic Constraints 显示文摘 | Guo Junxian Xiang Jinwu | 2004 | Journal of Aeronauties2004，17，3： | 1 |
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