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2003 Vol. 29, No. 11

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Numerical study of flow around a main cylinder by controlled satellite cylinders
Lee Chunhian, Peng Shaobo, Wu Ziniu
2003, 29(11): 951-958.
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Vortex shedding behind circular cylinder, when placing single or multiple secondary, much smaller cylinders in the near wake of the main cylinder, was numerically investigated using overlapping grids in conjunction with a domain decomposition method for the compressible Navier-Stokes equations. The effortsof the present study were paid toward the influences of Reynolds number, the locations and the number of the secondary cylinders, upon the flowfield structures and their evolution for low Reynolds number. The existing of an optimal suppressive region over the vortex flow fields at low Reynolds number was discovered, regardless of the number of the small cylinders. When controlling cylinders are located at the optimal position, vortex street is completely suppressed and the flow achieves a quasi-stationary state; at the same time, substantial reduction of the net drag coefficient is noticed. In a way, vortex shedding suppression is comparatively easier for a larger controlling cylinder. It is also found that the vortex street suppression by two controlling cylinders can sustain to higher Reynolds numbers by comparing with a single cylinder.
Advanced technologies of the integrated aircraft utility system and ECS
Wang Jun, Liu Yongji, Dong Sujun
2003, 29(11): 959-963.
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Two trends of the aircraft utility system integration technology of USA are introduced. The concepts of its key technologies, such as the integrated utilities management system, more electric aircraft, "hot fuel tank" integrated fuel system, integrated power unit and thermal/energy management module are presented in detail. And the advanced environmental control system(ECS) technologies of the modern military aircraft are emphasized at last.
Study on the dynamic plastic response and failure of structure modeling aerospace vehicle
Yang Jialing, Zhang Ya, Liu Xuhong
2003, 29(11): 964-969.
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The advances in the study on the dynamic plastic response and failure of structure modeling the aerospace vehicle subjected to intense dynamic loading are reviewed. Attention is focused on the basic research progress made by the authors and their cooperators in recent years in the study by using rigid-perfectly plastic and/or elastic-perfectly plastic models as well as the relevant experimental observations.
Unsteady lift mechanisms and energetic in flying insects
Sun Mao, Wu Jianghao
2003, 29(11): 970-977.
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Recently, the interest has been developed in small autonomous flying vehicles. There already exist such autonomous MAVs(micro\|air vehicles) in nature: the insects. In the design of small flying machines, it is very helpful to understand first how these small animals fly. The achievements of the last ten years in the field of insect flight aerodynamics are reviewed. First, the kinematics of the flapping motion of insects is summarized. Next, issues related to the unsteady lift mechanisms of flapping wings of the fruit fly and similar insects are presented. Then the power requirements of hovering and forward flight are discussed. Finally, recent works on the insects that have two pairs of wings are discussed.
Brief review of studies on the mechanical behavior of metallic foams
Lu Zixing, Guo Yu
2003, 29(11): 978-983.
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A brief review of studies on the mechanical properties of metallic foams is given. The emphasis is placed on the development of investigations into mechanical properties of metallic foams in recent years, including some works of this field in our country. They are mainly concerned with the tensile and compressive behavior, energy absorption, dynamic impact, failure criterion and constitutive relation, creep, fatigue and fracture of these materials. Finally, some future development trends are also presented.
Experimental investigations of the respective and synergistic effects of vacuum ultraviolet radiation and atomic oxygen on a spacecraft material——Kapton
Shen Zhigang, Zhao Xiaohu, Xing Yushan, Ma Shulin
2003, 29(11): 984-987.
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Kapton is a commonly used spacecraft material, on which the experiments are constructed to investigate the VUV (vacuum ultraviolet radiation) effects and its synergistic effects with AO (atomic oxygen) in a ground-based simulation facility. The sample materials before and after the tests are compared in appearance, mass loss, surface morphology, optical properties and surface composition. Through the analysis of the reaction mechanism between VUV, AO and Kapton, it was concluded that the oxidation of the carbon and nitrogen is the main reason of the erosion of Kapton. Because the sample surface will be cross-linking and form large molecule under VUV radiation, the AO-resistance characteristic of thesample is improved. But with the increasing of AO fluence, the effect disappears gradually, and the VUV cannot affect the results of the AO exposure experiment.
Static analysis of hybrid smart composite structures
Wang Jun, Li Zhengneng, Wang Junbing
2003, 29(11): 988-992.
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A hybrid smart structure integrated with shape memory alloy slims and piezoelectric ceramic patches as united actuators, was presented and modeled by finite element methods. Being bonded to its surface or embedded in the laminate, the piezoelectric ceramic patches was treated as a certain layer while the shape memory alloy slims as the load subject to the temperature. The comparison among the effects of different control methods was given, and validated with static experiment. The result indicate that the shape control of the hybrid smart structure can take advantage of their characteristic with shape memory alloy actuators holding the mostly load and piezoelectric ceramic actuators correcting the precise shape.
Variable strategy pilot model of carrier landing approach
Qu Xiangju, Cui Hailiang
2003, 29(11): 993-997.
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A variable strategy pilot model for carrier landing approach is presented. The model was integrated with two components: a discontinuous component of the acquisition strategy for a large deviation of glide path and a continuous component of pursuit tracking strategy for a small deviation. The variable structure model was based on the sliding mode control theory to switch the different control strategies of acquisition and pursuit tracking. Parameters of switching surface were extracted from literature of pilot training and pilot experience. The continuous component was constructed by classical models of pilot transfer functions and the parameters were evaluated in accordance with the crossover model theory. The simulation results of a carrier landing approach show the rationality and validity of the model.
Servo-elasticity test of an aircraft with the flight control system
Zhang Junjie, Yang Chao
2003, 29(11): 998-1000.
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To discover the servo-elasticity stability nature of an aircraft equipped with a flight control system, some active-control-system/structural dynamics interaction tests on it have been performed. The test principle and test method was described. Some typical test results have been presented and compared with the calculated results. The test method is reasonable.
Properties of stitched composite laminates——the principle properties of simple laminates
Cheng Xiaoquan, Zhao Long, Zhang Yining
2003, 29(11): 1001-1005.
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In order to solve the application of stitched composites in aircraft structures, experimental studies were carried out on the effect of stitching and stitching directions on tensile and compressive properties of unidirectional laminates and cross-ply symmetric laminates made of uniweave T300/QY9512. Some principle properties of uniweave T300/QY9512 were measured. It shows that stitching and stitching directions have little effect on the modulus of this two kind of laminates, while the effect is great on Possion ratio. The transform of off-axial modulus is not fit for Poisson ratio of off-axial stitched unidirectional laminates. Stitching and its directions have great effect on tensile strength of unidirectional laminates, but are not obvious on their compressive strength. Because the tension failure mechanisms of stitched cross-ply symmetric laminates are different from that of stitched unidirectional laminates, the strength of stitched unidirectional laminates cannot be used as the laminar strength of stitched cross-ply symmetric laminates.
Robust reliability of structural vibration
Wang Xiaojun, Qiu Zhiping
2003, 29(11): 1006-1010.
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Based on the conventional probabilistic design methods of structural vibration, modeling uncertain variables as interval (hyper-rectangle), a non-probabilistic interference model between the exciting frequencies and the natural frequencies of a structure was established and a non-probabilistic method of reliability analysis was presented, called robust criterion of reliability of structural vibration. A measure of reliability developed here is the amount of the uncertainty structure can tolerate before occurring resonance. The larger the structure can tolerate the amount of uncertainty, the more reliable, vice versa. It can be described as the partial order relation between the hype-rectangles in mathematics. Numerical example illustrates the feasibility of the presented non-probabilistic robust reliability criterion.
Researches on the resolution of fast large time step entropy condition scheme
Dong Haitao, Lee Chunhian
2003, 29(11): 1011-1016.
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A method of high resolution fast large time step entropy condition scheme is designed. A class of entropy schemes is studied with shock tube problems for numerical examples. Numerical experiment is carefully designed to study the accuracy, time step, and limiters of the schemes. The quality of different schemes is compared under the same computing time. The nonoscillatory property is guaranteed theoretically for large time step schemes. The resolution problem for large time step schemes is verified via the analysis of numerical experiments.
Improvement of taxing performance for civil airliner by active control
Jia Yuhong, Liu Ying
2003, 29(11): 1017-1021.
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Based on two performance indexes of vertical acceleration and vertical displacement of body, by the non-linear model of self-tuning of landing gear and the ARAMX model of system, using the design of controller of the multi-step recursive predictor and the identification of the model parameters and system structure, the self-tuning control of landing gear was implemented. The simulation results show that the control scheme can effectively improve the performance of taxing for civil airliner.
Research on scheme effect of computational fluid dynamics in aerothermal
Li Junzhe, Yan Chao, Ke Lun, Zhang Shuting
2003, 29(11): 1022-1025.
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The hypersonic flows around the two-dimension cylinder and three-dimension biconic are simulated by solving the N-S equations with computational fluid dynamics(CFD) method to get the heat transfer rate. For solving the N-S equations, Roe's FDS scheme, Van leer's FVS scheme, AUSM+ scheme and a center scheme are employed. All of the results are compared with the experimental data. For AUSM+ scheme, minmod limiter and double minmod limiter are used and compared with each other.
Design, modal analysis and tests of composites wing box
Liu Bingshan, Yan Ying, Qian Wei, Duan Yuexin
2003, 29(11): 1026-1028.
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A scaling-down wing-box model was designed on the basis of structural similarity and manufactured by means of integral-forming of composites for modal analysis and test, in which the similarity of structural dynamics and loading transfer were realized at the same time. The modal analysis and test was done and the results were in good agreement. This model lays a foundation of the flutter test of high-speed wing in low-speed wind tunnel.
Equivalent inter-phase model of dynamic response to thin layer of different mechanical properties in engineering structures
Zhang Jin, Li Zailiang
2003, 29(11): 1029-1032.
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The dynamic response of an infinite long elastic rod with a thin layer of different mechanical properties has been investigated. Three equivalent inter-phase models of elastic thin layer have been used: simple spring, spring plus mass and modified spring. The dynamic response of the rod has been simulated effectively by last two models: the reflection and transmission coefficients of longitudinal waves are in good agreement with the exact results in a rather wide low frequency region. The modified spring model proposed in this work is better than common spring plus mass model: the inertia has been considered, and its form is as simple as simple spring.
Unsteady structures over delta wings
Zhu Liguo, Lü Zhiyong
2003, 29(11): 1033-1037.
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Visualization with light sheet and PIV tests were performed to investigate some unsteady structures over delta wings. Discrete sub-vortices in the vortex sheet, interaction of the secondary vortex with main vortex, the frequency characteristics of the spiral form of vortex breakdown, the fluctuation of breakdown location, and vortex shedding at high angles of attack were studied respectively. Different frequency is given for unsteady structures.
Study of active shape control of SMA reinforced composites and the neural network model
Zeng Shenchang, Mai Hanchao, Wu Sheng
2003, 29(11): 1038-1041.
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NiTi SMA wires were embedded in the composite laminate beyond the neutral layer, and by electric current, they are heated up to produce the large recovery force. Consequently, the bending deformation of SMA reinforced structure is achieved. Due to the nonlinear behavior of SMA and the complexity of the principles of stress, strain and shape of the composite structure embedded with SMA wires, use the artificial neural network to establish the model of steady-state deflection-intensity of electric current. Eventually, the relative error between the expected date of the model and the experimental data is less than 9%.
Research on integrated flight/propulsion control design
Jiang Zaiming, Zhang Shuguang
2003, 29(11): 1042-1046.
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A decentralized approach was set up for integrated flight/propulsion control(IFPC) design. Based on the gliding slope and terrain-following(TF) missions, the structures of compensators were firstly determined. The linear quadratic optimization with output feedback method was applied to determine the zeros of the compensators and the feedback gains. The effects of coupling factors between the velocity and the altitude paths were analyzed. The results show that if the coupling factors and weighting matrix for choice of the zeros of the compensators and the feedback gains are properly used, good control schemes are available, and the linear quadratic optimization with output feedback for IFPC design is favorable.
Application of wavelet transform for laminate real time injuries measuring
Lu Dawei, Li Shu
2003, 29(11): 1047-1050.
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The wavelet analysis is adopted in this article for dealing with the signal. The main subject is calculating the dynamics response of samdwich board. Then decompose the structure response signal with wavelet tools after deducing the annoyance. The real-time monitoring for composite material is carried out by catching the damaging moment. Then choose the damage character by comparing the susceptibility to damage among every response signals.
Research of target identification based on cognitive characteristic
Zhuang Damin, Wang Rui
2003, 29(11): 1051-1054.
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To optimize the design of plane's human-machine interface, assume the shape, size and responding time of target(character or mark) according to human cognitive characteristic, and analyse and validate it by two-dimension target identification experiment. The result of experiment suggests that the quantification of the target size and responding time is reasonable, the target shape influences target identification as well as the former research and the target position and color have little effect on target identification within the range departuring from center vision less than 10°.
Research on droplet impingement property of rotor blade in hover
He Zhi, Chang Shinan, Yuan Xiugan
2003, 29(11): 1055-1058.
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The numerical method of determining the water droplet impingement property of rotor blade in hover was studied. According to the quasi-steady property, the rotor's model in hover was simplified. Based on the calculation of flow field around the blade, the droplet trajectories were obtained through the difference method. And then, the parameters of droplet impingement on blade were given, which provided the conditions for rotor anti-icing/deicing system design. Finally, the impingement properties of NACA0012 were presented as an example.

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