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Zhang L.,Beihang University | Zhang H.,AVIC Chengdu Aircraft Design and Research Institute | Yang Y.,Beihang University | Huang L.,Beihang University
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2012

The success of an aerial refueling task depends on the successful docking between the refueling drogue and the probe of the receiver aircraft. The study of contact dynamic behaviors during the process is the prerequisite to realize successful docking. A dynamics model of the docking process is established according to the multi-body dynamics theory to obtain the generalized velocity between the refueling drogue and the receiver aircraft. The relative velocities among local contact points are obtained through the contact dynamics model that has been established. Based on the nonlinear continuum collision theory, this paper proposes a calculation method of the collision force during the docking process. Meanwhile, a virtual prototype for docking is created by means of software ADAMS. The response curves of the collision force and velocity are obtained through dynamic simulations of the virtual prototype. Meanwhile, the specific ranges of each parameter in a successful docking are obtained. The results indicate that there are three main parameters that affect the docking process: the initial relative velocity, the pitch angle of the refueling drogue and the centerline offset between the refueling drogue and the probe. The study is significant to the docking process and receiver aircraft navigation in an aerial refueling.


Cao Y.,Beihang University | Chen K.,AVIC Chengdu Aircraft Design and Research Institute
Aeronautical Journal | Year: 2010

Due to constraints of natural condition, cost and of available time associated with model fabrication and for extensive wind-tunnel tests or flight tests, Computational Fluid Dynamics (CFD) simulation was considered an alternative means of providing air vehicle icing simulation and aeromechanic performance analysis. Full-scale icing experiments and, therefore, certification and cost can be significantly reduced by developing full-numerical simulation methods to evaluate the air vehicle performance for a wide range of icing conditions. This paper summarises helicopter icing simulation methods that include the development of helicopter aerodynamics, calculation methods of helicopter icing, icing protection system performance, icing effects on the helicopter performance, and some challenges in helicopter icing simulation.


Zhu W.,Xi'an Jiaotong University | Li D.,Xi'an Jiaotong University | Zhang Z.,China Aerodynamics Research And Development Center | Ren K.,AVIC Chengdu Aircraft Design and Research Institute | And 5 more authors.
Rapid Prototyping Journal | Year: 2011

Purpose - The purpose of this paper is to present a novel method to design and fabricate aeroelastic wing models for wind tunnel tests based on stereolithography (SL). This method can ensure the structural similarity of both external and internal structures between models and prototypes. Design/methodology/approach - An aluminum wing-box was selected as the prototype, and its natural modes were studied by FEA and scaled down to obtain the desired dynamic behavior data. According to similarity laws, the structurally similar model was designed through a sequential design procedure of dimensional scaling, stiffness optimization and mass optimization. An SL model was then fabricated, and its actual natural modes was tested and compared with the desired data of the prototype. Findings - The first two natural frequencies of the model presented strong correlation with the desired data of the prototype. Both the external and internal structures of the model matched the prototype closely. The SL-based method can significantly reduce the total mass and simplify the locating operations of balance-weights. The cost and time for the fabrication were reduced significantly. Research limitations/implications - Further investigation into the material properties of SL resins including stiffness and damping behaviors due to layered process is recommended toward higher prediction accuracy. Wind tunnel tests are needed to study the ITin situ/IT performance and durability of SL models. Originality/value - Although the paper takes a wing-box as the study object, structurally similar SL models of entire wings can be obtained conveniently, benefiting from the low-stiffness material properties of SL resins and the fabrication capacity to build complex structures of SL process. This paper enhances the versatility of using SL and other rapid prototyping processes to fabricate models to predict aeroelastic characteristics of aircraft. © 2011 Emerald Group Publishing Limited. All rights reserved.


Xu Y.,University of Electronic Science and Technology of China | Li X.,University of Electronic Science and Technology of China | Chang H.,University of Electronic Science and Technology of China | Wang Y.-X.,AVIC Chengdu Aircraft Design and Research Institute
Ruan Jian Xue Bao/Journal of Software | Year: 2012

With the expansion of distributed multi-agent system applications and the increasing scale of the system, the characters of complex network have become an important factor in system performance. This paper makes an initial effort to find the effects of complex network characters on large-scale distributed multi-agent coordination to create a systemic analysis of the system performance and provide organization optimization algorithm designs. The study primarily investigated typical complex networks: random network, small-world network, grid network and scale-free network in multi-agent coordination on theoretical analysis and practical simulations. In theoretical analysis, the study has built the cooperative information transmission model based on Markov chain over different network topologies and compared their efficiencies on either random walk or intelligent routing model. In addition, the study explored the characters of complex network in three main coordination simulations: cooperative information transmission, multi-agent team coordination, and multi-agent network recovery. It is found that the characters of complex network such as small-world or scale-free attributes will bring significant differences in spite of the same coordination schema, and it is feasible to design some desired intelligent algorithms to take the advantage of those effects so that system performance can be promoted. © 2012 ISCAS.


Guancheng F.,Northwestern Polytechnical University | Guancheng F.,AVIC Chengdu Aircraft Design and Research Institute | Zhenzhou L.,Northwestern Polytechnical University | Wenbin R.,Northwestern Polytechnical University
Journal of Aircraft | Year: 2016

For importance analysis of structural models with correlated inputs, a new method combining support vector machine regression and the single-loop Monte Carlo technique is proposed. In this new combined method, the correlated inputs are transformed to uncorrelated ones by orthogonally independent transformation first, then support vector machine regression is employed to establish the multiple-dimensional regression models involving all inputs, on which the single-loop Monte Carlo is used to obtain the importance measures of the correlated inputs. Support vector machine regression is also used to establish the one-dimensional regression model involving one concerned input. This direct support vector machine regression is proposed as a comparative method. Profiting from the high efficiency of support vector machine regression, the combined and direct methods can get the importance analysis results of the correlated inputs more efficiently than the Monte Carlo simulation. By comparing the results of combined single-loop Monte Carlo technique and those of the direct method, it is found that the former is more efficient and robust than the latter. Several examples illustrate the efficiency and accuracy of the proposed methods. Copyright © 2015 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.


Sang J.,AVIC Chengdu Aircraft Design and Research Institute | Zhang Z.,AVIC Chengdu Aircraft Design and Research Institute
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2013

With the development of science and technology, infrared stealth technology has been widely used in new weapons and equipments, and it has become an important performance and significant feature of the modern weapon equipment. The birth of the infrared sensors for missile seeker applications becomes a major threat for various types of weapons and equipments, especially for infrared detectors. The threats to weapons were analyzed; infrared stealth performance of the various types of weapons and equipment and development of the infrared stealth was summarized; the sources of infrared radiation, control technology measure of IR and development tendency were briefly analyzed for fixed wing aircraft as the key, but also for helicopters, surface ships and ground weapon equipments. The test results prove that research and application of the infrared stealth technology are important to all kinds of weapons and equipments.


Wenqing S.,AVIC Chengdu Aircraft Design and Research Institute | Zhengzhong Y.,AVIC Chengdu Aircraft Design and Research Institute | Lei Z.,AVIC Chengdu Aircraft Design and Research Institute
29th Congress of the International Council of the Aeronautical Sciences, ICAS 2014 | Year: 2014

An automated control strategy was proposed in the article to solve the flameout landing problem encountered by High Altitude Long Endurance Unmanned Aerial Vehicle (HALE UAV) during its mission flight. Theoretical analyses of HALE UAV flight characteristics after engine failure were discussed at first to establish the control strategy design principles. Modelling and simulation of flameout flight dynamics, flight control and state transition were carried out to facilitate the detail design, optimization and verification of the control strategy. A number of designated and random simulation cases including those in complicated situations were tested. Statistical results showed that a satisfactory success rate was finally reached by using the proposed automated control strategy.


Zhang S.,Nanjing University of Aeronautics and Astronautics | Shan Y.,Nanjing University of Aeronautics and Astronautics | Zhang J.,Nanjing University of Aeronautics and Astronautics | Zhang Y.,AVIC Chengdu Aircraft Design and Research Institute
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2012

Based on computational fluid dynamics/infrared radiation (CFD/IR) numerical calculations and validated by experiment, the effect of nozzle pressure ratio and geometry-vector angles of a single expansion ramp nozzle (SERN) on its aerodynamic and infrared radiation characteristics is studied. The results show that when the geometry-vector angle is 0° and the nozzle pressure ratio is low, the aerodynamic characteristic of the nozzle decreases significantly, largely because of over expansion. When the geometry-vector angle is negative, over expansion is more serious and aerodynamic characteristic decreases. With the increase of the absolute value of the geometry-angle, the vector thrust increases, but the thrust coefficient decreases. When the geometry-vector angle is changed from -25° to 25° and the nozzle pressure ratio is changed from 3 to 6, the smallest thrust coefficient is about 0.88 and the biggest thrust coefficient is about 0.98. When the geometry-vector angle is 5°, the infrared radiation of the plume is biggest. When the geometry-vector angle moves away from 5°, the infrared radiation of the plume becomes smaller, but its distribution is not changed. With the variation of the geometry-vector angle, the total infrared radiation of the nozzle presents a different distribution. When the geometry-vector angle is negative, the detecting angle with large infrared radiation is at the underside. When the geometry-vector angle is positive, the upside of the nozzle has large infrared radiation. These are determined by the visible area of the inner wall of the ramp and nozzle lumen.


Ma Y.,Northwestern Polytechnical University | Xia Z.,Northwestern Polytechnical University | Xiong X.,AVIC Chengdu Aircraft Design and Research Institute
Science China: Physics, Mechanics and Astronomy | Year: 2014

Fiber-metal laminates (FMLs) consist of three layers of aluminum alloy 2024-T3 and two layers of glass/epoxy prepreg, and it (it means FMLs) is laminated by Al alloy and fiber alternatively. Fatigue crack growth rates in notched fiber-metal laminates under constant amplitude fatigue loading were studied experimentally and numerically and were compared with them in monolithic 2024-T3 Al alloy plates. It is shown that the fatigue life of FMLs is about 17 times longer than monolithic 2024-T3 Al alloy plate; and crack growth rates in FMLs panels remain constant mostly even when the crack is long, unlike in the monolithic 2024-T3 Al alloy plates. The formula to calculate bridge stress profiles of FMLs was derived based on the fracture theory. A program by Matlab was developed to calculate the distribution of bridge stress in FMLs, and then fatigue growth lives were obtained. Finite element models of FMLs were built and meshed finely to analyze the stress distributions. Both results were compared with the experimental results. They agree well with each other. © 2013 Science China Press and Springer-Verlag Berlin Heidelberg.


Ma Y.,Northwestern Polytechnical University | Hu H.,Northwestern Polytechnical University | Xiong X.,AVIC Chengdu Aircraft Design and Research Institute
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2014

In order to improve the damage tolerance and anti-impact properties of aircraft structures, fiber metal laminates (FMLs) developed in Europe are successfully applied in commercial aircraft structures. In this paper, drop-weight low-velocity impact tests are performed on FMLs which consist of 2024-T3 aluminium alloy sheets bonded together by glass fiber prepreg. For comparison purposes, similar tests are conducted on monolithic 2024-T3 sheets and F300 quasi-isotropic composite panels. The penetration energy of the FMLs shows respectively about 40% and 6 times higher than that of the 2024-T3 sheets and composite panels; and the back side crack length of the FMLs is 30%-50% shorter than that in the 2024-T3 sheets at the same level of impact energy. Finite element models are developed to simulate the impact response of the FMLs. Ductile and Hashin damage initiation criteria are used to simulate the aluminium and fiber failure mechanisms respectively. The dynamic response of the laminates is analyzed and the damage mode is summarized. The simulation results agree well with the experimental findings.

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