Shenyang Aircraft Design Institute
Nan L.Y.,Shenyang Aircraft Design Institute |
Mo Z.,65012 PLA
Proceedings of 2016 IEEE International Conference on Electronic Information and Communication Technology, ICEICT 2016 | Year: 2017
Applications of multicast technology in space information network are increasing year by year. Due to the inherent characteristics of space information network, the existing multicast protocols are difficult to meet the high-quality service requirements and the need for reliability. A coding-aware and load balancing reliable multicast protocol in space information network is proposed. A coding-aware and load balancing routing metric is designed. This paper defines a load balancing factor to measure load status of the node and the Expected Transmission Time with Coding to measure the coding gain. A new route metric ECTTL (Expected Transmission Time with Coding and Load balancing) which combines the two factors is designed to select the high throughput path routes. It not only has the potential coding opportunity but is also able to prevent routing node overflows due to overload. In route establishment process, according to different business needs, it is preferable to use ECTTL metric to build multipath multicast tree and network coding method to encode the data for transmission. The coding-aware load balancing and reliable multicast protocol LCRM is simulated and analyzed in NS-2 simulation platform, The results showed that the design of coding-aware load balancing and reliable multicast protocol LCRM had good performance in reducing the end-to-end delay, routing overhead and improving the network throughput. © 2016 IEEE.
Huo L.,Shenyang Aerospace University |
Fei S.,Shenyang Aircraft Design Institute
Beijing Hangkong Hangtian Daxue Xuebao/Journal of Beijing University of Aeronautics and Astronautics | Year: 2017
Aircraft management system is an important part to guarantee flight safety, and redundancy design is the main method to improve the safety of the system. The redundancy design, however, is constrained by the budget (economy) in the design and manufacture and the consumption of the maintenance support resources (reliability). According to the safety, basic reliability and economy models of aircraft management system, a redundancy configuration optimization method was proposed by using the improved integer optimal genetic algorithm, with safety as the objective, and basic reliability and economy as the constraint. Then an example was taken to show its effectiveness to the complex system redundancy optimization. The sensitivity analysis shows that the safety optimal value declines with the increase of the basic reliability lower bound, and rises with the increase of the economy upper bound. For two constraints on the optimization of the objective competitive constraints, at the same time only one constraint condition plays a major constraint role. These two constraint conditions play a role in the competition, and at the same time there is only one main constraint. © 2017, Editorial Board of JBUAA. All right reserved.
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.
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.