Duan H.,Beihang University |
Shao S.,Shenyang Aircraft Design Institute |
Su B.,China Aerospace Science and Technology Corporation |
Zhang L.,Academy of Equipment Command and Technology
Science China Technological Sciences | Year: 2010
Bio-inspired intelligence is in the spotlight in the field of international artificial intelligence, and unmanned combat aerial vehicle (UCAV), owing to its potential to perform dangerous, repetitive tasks in remote and hazardous, is very promising for the technological leadership of the nation and essential for improving the security of society. On the basis of introduction of bio-inspired intelligence and UCAV, a series of new development thoughts on UCAV control are proposed, including artificial brain based high-level autonomous control for UCAV, swarm intelligence based cooperative control for multiple UCAVs, hybrid swarm intelligence and Bayesian network based situation assessment under complicated combating environments, bio-inspired hardware based high-level autonomous control for UCAV, and meta-heuristic intelligence based heterogeneous cooperative control for multiple UCAVs and unmanned combat ground vehicles (UCGVs). The exact realization of the proposed new development thoughts can enhance the effectiveness of combat, while provide a series of novel breakthroughs for the intelligence, integration and advancement of future UCAV systems. © 2010 Science China Press and Springer-Verlag Berlin Heidelberg.
Duan H.,Beihang University |
Xu C.,Beihang University |
Liu S.,Beihang University |
Shao S.,Shenyang Aircraft Design Institute
Pattern Recognition Letters | Year: 2010
Image matching plays an important role in feature tracking, object recognition, stereo matching, digital photogrammetry, remote sensing, and computer vision. Imperialist competitive algorithm (ICA) is inspired by imperialistic competition mechanism. In this paper, we present a novel template matching method based on chaotic ICA. Based on the introduction of the principle of ICA, the correlation function used in this approach is proposed. The chaos can improve the global convergence of ICA, and the phenomena of falling into local best solution can be prevented. The detailed process for chaotic ICA-based template matching is also presented in detail. The three typical comparative results show that our proposed chaotic ICA image matching approach is more efficient and effective than the basic ICA. © 2010 Elsevier B.V. All rights reserved.
He X.,Beihang University |
Sui F.,Shenyang Aircraft Design Institute |
Zhai B.,Beihang University |
Liu W.,Beihang University
Engineering Failure Analysis | Year: 2013
Scatter of fatigue life of a fleet is mainly caused by the variability in structures and load spectra. To ensure the safety in service, the probabilistic characterization of load spectrum variability should be researched in durability analysis and testing work. This paper investigates the variability of load damage rate of a fleet. Based on the flight historical parameters measured by individual aircraft tracking (IAT) from hundreds of aircrafts for a certain type of fighter in China, SWT formula and linear damage rule are used to evaluate the load damage, and then, one average and four other individual load spectra are selected corresponding to different damage severities. Fatigue tests are conducted with the Aluminum alloy 7B04-T74 specimens under five spectra and the Titanium alloy TA15M specimens under three of them. The engineering crack initiation lives are measured and the mean lives are estimated assuming the fatigue life following a log-normal distribution. An obvious difference of at least 2.4. times in the load damage rates is found in the fleet. The fatigue lives of a fleet of aircrafts are calculated by Neuber's approach, and the probabilities refer to damage severities of those 5 load spectra in a fleet are evaluated. The statistical analysis of the fatigue lives and the probabilities shows that a lognormal distribution can be used to describe the variability of load damage rate of a fleet. The variation of the load damage rate is in the same order of magnitude with that in structural properties. © 2013 The Authors.
Wang A.,Wuhan University of Technology |
Wang A.,Hubei University |
Wang W.,Wuhan University of Technology |
Long C.,Wuhan University of Technology |
And 4 more authors.
Journal of Materials Chemistry C | Year: 2014
An easy and flexible two-step approach consisting of annealing and subsequently selective pitting corrosion has been developed to prepare porous carbonyl iron flakes (CIFs). Based on the dependence of the morphologies and compositions of the resultant CIFs on the annealing temperature and corrosion time, a formation mechanism for the porous CIFs has been substantiated. In our protocol, the annealing process carried out as the first step in the formation process causes an increase in the grain size and forces the Fe nanocrystals to react with the N impurities in the raw CIFs to generate dispersed Fe 4N domains. These domains subsequently induce selective pitting corrosion, resulting in porous CIFs. As a result of the porous structure, the as-obtained porous CIFs have a specific surface area of 16.92 m2 g-1, a saturation magnetization of 140 emu g-1 and a coercivity of 61 Oe. Compared with the raw CIFs, they have a large permeability at high frequencies and a modest permittivity. Consequently, composites containing 20 vol% of the porous CIFs in paraffin wax display a reflection loss ≤-20 dB over a wide frequency range of 2.9-20 GHz when the thickness is varied between 0.9 and 4.5 mm. The results reported here suggest a facile approach to preparing porous nanocrystalline metals. Our results offer a promising strategy for the fabrication of absorbents for thin-thickness and strong-absorption microwave absorbing materials with working frequencies adjustable over a wide range simply by varying the thickness. © 2014 the Partner Organisations.
Zong-Xin Y.,Shenyang Aircraft Design Institute
28th Congress of the International Council of the Aeronautical Sciences 2012, ICAS 2012 | Year: 2012
The ASP (Aero-Space Plane) ascent trajectoryoptimization is a difficult problem due to thecomplexity of operating the combined cyclepropulsion and the absence of the enough andexact aerodynamic characteristic data duringthe process of calculating the dynamics modelin order to achieving cargo delivery to LEOorbits.In this paper, to acquire the optimizingascent trajectory of a hypothetical ASP, it isestablished that the flight dynamics model of theASP which can take off and land horizontally;The method of optimizing the ASP's ascenttrajectory is designed by adjusting someparameters such as the flight-path angle, theangle of attack, and the cycle work models ofthe turbine and rocket-ramjet combined, etc.Finally, the optimizing simulation of the ascenttrajectory has been finished based on theaerodynamics and propulsion data whichproduced in other projects, while it is obtainedthat the primary results about the optimizingresearch on the ascent trajectory.It is very important for the ASP that theflight process from takeoff to launch payload,because the ASP will consume a majority of thefuel in the flight progress. The trajectory of theASP in a certain flight process is the mostprimary factor which affects those parametersconsisting of the takeoff total weight, the ratio ofthrust to weight, the ratio of lift to drag, theengine's thrust force, and the engine's fuelconsuming amount per unit time, etc. Therefore,it is an indispensable approach to determinethose parameters for the ASP's concept designthat the optimizing research on the ASP's ascent trajectory.
Guan D.,Shenyang Aircraft Design Institute |
Cai W.,Shenyang Aircraft Design Institute
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2014
A number of spoilers are designed in the leading edge of the weapons bay which may possibly control the flow and improve the yawing moment characteristic in the missile separating course so as to force the missile's head to reverse for the safety of the separation yawing. To study the problem, spoilers of different heights are built in the leading edge of the weapons bay through theoretical analysis and a wind tunnel test is conducted to measure the forces acting on the parts so as to study the spoilers' effect on the flow patterns in the bay and the missile's yawing moment characteristics. Furthermore, the spoilers' effect on the missile's yawing separation characteristics is analyzed, and the credibility of the separation yawing attitude angle characteristic analysis is validated by a track capture wind tunnel test. The result shows that designing spoilers with certain heights in the leading edge of the weapons bay can effectively control the flow patterns in the bay, improve the missile's yawing aerodynamic characteristic, and improve the separating yawing safety.
Zheng G.N.,CAS Institute of Mechanics |
Yang G.W.,CAS Institute of Mechanics |
Qian W.,Shenyang Aircraft Design Institute
Science China Technological Sciences | Year: 2013
A tightly coupled method was developed to analyse aeroelasticity by constructing subiterative schemes for fluid and structural equations of motion, respectively. With MPI partition parallel computing, the fluid was solved by Navier-Stokes equations based on hybrid grids. A new unstructured background grid deformtion method was used for the CFD grid deformation. The transonic flutter wind tunnel model of a complete aircraft was simulated to validate the developed method. The flutter characteristics of the aircraft was analysed and compared with the test results. It indicates that the devoloped method has a relatively higher precision and can be used for aeronautical engineering application. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.
Zhang P.,Nanjing University of Aeronautics and Astronautics |
Zhou L.,Nanjing University of Aeronautics and Astronautics |
Qiu T.,Shenyang Aircraft Design Institute
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2011
Morphing aircraft require the airfoil camber to change continuously and smoothly. The flexible skins must have substantial in-plane expansion deformability, while at the same time it must be able to bear the out-of-plane aerodynamic loads. In this article, a new flexible honeycomb structure is designed for the wing with a variable camber trailing edge. The relationship between the in-plane deformability and the shape parameters of the flexible honeycomb are studied. Simulation and experimental studies are carried out for the flexible honeycomb. The results show that the flexible honeycomb has substantial in-plane deformability and maintains good out-of-plane bearing capacity, which satisfies the application requirements of the wing with a variable camber trailing edge.
Yao Z.-X.,Shenyang Aircraft Design Institute
29th Congress of the International Council of the Aeronautical Sciences, ICAS 2014 | Year: 2014
In this paper, the Least-Squares (LS) method is used for aerodynamic model identification of a scaled UAV designed for researching the high Mach number aircraft. The LS module is composed of State Matrix, Parameter Measure Vector, Parameter Estimate Vector, and Parameter Estimate Covariance, and so on. The equation-error method calculates aerodynamic parameter estimates that minimize squared errors between values of the non-dimensional force and moment coefficients determined from measured flight data, and model values computed from the aerodynamic model based wind-tunnel test data. For conducting the Aerodynamic Model Identification study, the appropriate data are elaborately selected from the whole flight test data based on some rules. Results presented in the paper show that the identification of lift coefficient derivative about Angle-of-Attack agrees well with the aerodynamic model based on wind-tunnel test data.
Li H.-E.,Shenyang Aircraft Design Institute |
Sha A.-X.,Aerospace Research Institute of Materials And Processing Technology
Cailiao Gongcheng/Journal of Materials Engineering | Year: 2010
The effect of strain rate and deformation temperature on the deformation resistance and the microstructure of TC18 titanium alloy was studied through heat simulating test at 700-950°C and strain rate 0.001-50 s-1. The results show that, when the deformation temperature increases or the strain rate decreases, the real stress can be reduced obviously. Comparing to deformation in β phase, deformation resistance in α+β phase is more sensitive to the change of temperatures. When α+β phase deformed, α and β phases join in deformation at the same time, but deformation degree is different. Preliminary equiaxed alpha phase is elongated slightly and beta phase changes to fiber texture along deformation direction. When β phase deformed, beta phase is fibrous along metal flowing direction, and equiaxed beta grain can be seen when the deformed temperature is above 950°C.