2015, 6(4):395-404. DOI: 10.16615/j.cnki.1674-8190.2015.04.001
Abstract:To evaluate the actual computational efficiency of the Fourier Time Spectral Method in the aspect of the time-discretization accuracy, accuracy analysis is performed on the computational solutions of two-dimensional transonic flows. Computational results of periodic flows over a pitching NACA0012 airfoil by solving unsteady Euler equations show that large time interval could be used for the Fourier TSM to model periodic transonic flows even when shock waves occur. Error analysis shows that, compared to the 2nd order Backward Difference Formula (BDF) method, the Fourier TSM is much more efficient in predicting the temporal variation of quantities that are integrated from the surface pressure coefficient, especially the lift coefficient. When predicting the temporal variation of the surface pressure coefficient, the computational efficiency of the Fourier TSM is not lower than that of the 2nd order BDF method.
Yang Xiaojuan , Liu ruoyang , shezhikun
2015, 6(4):405-411. DOI: 10.16615/j.cnki.1674-8190.2015.04.002
Abstract:Concerning the optimization of two-dimensional compressor blade,a optimization model based on Boundary Vorticity Flux (BVF) was proposed and solved. Starting from a optimization model:the boundary is two-dimensional compressor blade defined by Bezier curve and the optimization target is the minimize of positive peak of Boundary Vorticity Flux (BVF), a new objective function is established through that the information of blade curve are brought into BVF by analyzing the reason of BVF production.The new objective function can get partial derivation of the parameters of blade curve,which make the simple gradient arithmetic being used to solve the built optimization model.The optimization experiment shows that the positive peak of Boundary Vorticity Flux is effectively decreasing in this process.
WANG Yang , WU Wei-wei , LI Zhi-guo
2015, 6(4):412-418. DOI: 10.16615/j.cnki.1674-8190.2015.04.003
Abstract:The aerodynamic characteristics of forward-swept and back swept wing in ground effect was researched carefully by solving steady incompressible N-S equations. According to the computation of lift and drag coefficient for the same area wing with different forward swept and swept angle, we can get the aerodynamic characteristics of wings in free space and ground effect. As a result, lift/drag coefficient and lift-drag ratio decrease and aerodynamic center moves backward with the increase of backswept in ground effect. Meantime, downwash angle decreases with back-swept angle increasing. While with the increase of forward-swept angle, lift/drag coefficient decreases and aerodynamic center moves forward, but the lift-drag ratio almost keep constant. The results can provide theoretical basis for the programming and optimization of aircraft in ground effect.
2015, 6(4):419-426. DOI: 10.16615/j.cnki.1674-8190.2015.04.004
Abstract:Combined with the products characteristics of the commercial aircraft, study the definition of configuration, raise a multi-level configuration defined structure for the commercial aircraft for the first time. Take configurations control of the commercial aircraft as an example, use the "5W1H" analysis method for the first time to studies "the configuration control targets", "control objects", "the starting point of the configuration control", "configuration of control the roles and responsibilities", "configuration control processes and methods" and the control work environment. Analyze the existing problems and give advice at the same time.
MAO Yunhui , CHEN Qingyang , HOU Zhongxi , GUO Zheng
2015, 6(4):427-432. DOI: 10.16615/j.cnki.1674-8190.2015.04.005
Abstract:As a kind of the aeronautic aircraft, UAV(unmanned aerial vehicle) is born to have practical application value. A NLG(non-linear guidance) algorithm for UAV path tracking is actualized in the guidance outer-loop of the UAV flight control system, which is abstractly to have the wind resistance. Based on the virtual target on the path, the algorithm will instantaneously calculate the desired lateral acceleration of the UAV, and then get the roll angle command by the UAV motion equation. This guidance method can work on quite accurately only with the appropriate distance parameter L. To make up for the offset induced by the control inner-loop, a feedback term is considered and added into the original algorithm to get the modified one in closed loop. Simulation experiments were conducted under the lateral windy settings. Both the modified nonlinear guidance algorithm and the PLOS(pure pursuit with light of sight) algorithm were tested and compared. The results show the validity of the modified nonlinear guidance algorithm, and illuminate the wind resistance of it.
baixiaoqiu , Hu Xuepeng , Chen Jun
2015, 6(4):433-441. DOI: 10.16615/j.cnki.1674-8190.2015.04.006
Abstract:Aiming to study the influence on buckling performance and load-carrying capacity of composite stiffened panels subjected to the impact damage, an experiment was executed to compare the typical composite stiffened panels with impact damage to the perfect panels, considering the impact-resisting behavior brought by the section shape of the stiffener. The result indicated that there was no obvious influence on the buckling performance and load-carrying capacity of composite stiffened panels with impact damage acting on the bottom fringe and axis area of stiffener under the certain impact energy, and the T-shaped stiffened panel is better than the I-shaped stiffened panel in the performance of damage resistance.
2015, 6(4):442-446. DOI: 10.16615/j.cnki.1674-8190.2015.04.007
Abstract:Blended wing body (BWB) unmanned aerial vehicle (UAV) has good lift to drag and stealth characteristics, and has broad application prospects in both civil and military fields. In order to improve the endurance of the UAV, considering aerodynamic characteristic and structure weight requirement of blended wing body UAV, lift to drag radio and aircraft area are taken as optimization objectives, using Multi-objective optimization method to study configuration design of blended wing body UAV, putting forward a parameterized configuration optimization design method of UAV, and a practical example is given. The analysis results indicate that configuration optimization can increase lift to drag radio of UAV, reduce structure weight, and get an excellent design scheme of blended wing body UAV.
2015, 6(4):447-451. DOI: 10.16615/j.cnki.1674-8190.2015.04.008
Abstract:Flight loads measurement is necessary for new type aircraft developing. Control surface hinge moment measurement is an important part of Flight loads measurement for an aircraft. An flight loads measurement technique for short rods was proposed in this paper,the technique in this paper was applied to measure flight load at certain aircraft; The response coefficient of strain-gage bridge differences up 45% when pull & press calibration test for the short rods, so, the opinions of flight loads measurement for short rods need to calibration pull & press two loads case was proposed in this paper.
jiguoming , zhengpeiyun , dengmaojing , xujunqiang
2015, 6(4):452-459. DOI: 10.16615/j.cnki.1674-8190.2015.04.009
Abstract:In order to study motion feature of tiltrotor rotation mechanism during nacelle and the rotor turning 90 forward, and to find a more suitable rotation mode, the rotating mechanism of tiltrotor was set for the research object through a simplified mechanism model. There were three rotating patterns set for the rotating mechanism. The kinematic characteristics of each rotating pattern were calculated with MATLAB software. The rotation process of the rotating mechanism was simulated in three set patterns with LMS software. The identical curves of angular speed, speed, angular acceleration, and acceleration were plot with two kinds of software. After analyzing the various kinematic characteristic curves, we can obtain that the three patterns have their own advantages and disadvantages, as well as the applicable conditions and situations. They can be chosen due to the specific circumstances and needs.
2015, 6(4):460-464. DOI: 10.16615/j.cnki.1674-8190.2015.04.010
Abstract:This article expounds the importance of satellite solar wing mechanism among satellite products. On the basis of the reliability research situation of satellite solar wing mechanism, this article provides an analysis method based on Reliability safety coefficient for satellite solar wing mechanism Expanding movement. First, the reliability safety coefficient is introduced and derived; Second, using the parameters of a satellite solar wing mechanism to analyze and calculate. Finally, the result, compared with the method formulated by GJB, certifies the rationality and feasibility of proposed method, and provides a useful reference for reliability design of satellite solar wing mechanism.
ZhouHanwei , Yang Shipu , SiJiangtao
2015, 6(4):465-472. DOI: 10.16615/j.cnki.1674-8190.2015.04.011
Abstract:The distribution of Liquid Water Content(LWC) on different position of Aircraft nose were numerical analysed under different flight conditions in this paper. The air-water droplet flow field was numerical simulated using Computational Fluid Dynamic method. Navier-Stokes equations were solved to obtain the air flow field, and Eulerian Method was used to obtain the water droplet trajectories. With the computational results, the shadow height of water droplet and LWC change on key section on aircraft nose were analysed under different inflight Mach number and angle of attack, and the influence of Mach number and angle of attack on LWC were studied.
Zhang Yi , Guo Yinsai , Zhang Mengyi , Zeng Xiangfu
2015, 6(4):473-478. DOI: 10.16615/j.cnki.1674-8190.2015.04.012
Abstract:Mechanical structure as airborne evaporation circulatory system's main support, has great quality and vibration impact from the helicopter. Its performance affects the normal function of the whole system. On the premise of guaranteeing sufficient strength and rigidity of structure, lightweight design has important theoretical significance and practical value. For analysis of structure design, the actual stress distribution of the structure is well simulated by the method of finite element method (fem) analysis, solving the difficulties of analysis and calculation of complex structure parts, which fundamentally changed the traditional design method of experience. The structure is parametric designed by using real-time transfer function of parameters between Pro/E and Ansys Workbench. The critical dimensions of parameters model are got by using the sensitivity analysis, which have more influence the optimization goal. And then the multi-objective genetic algorithm is adopted to design its structure. The result is that the quality than the original dropped 24.4%. The optimal structure parameters are obtained to realize the lightweight of the structure.
HeJing , WuNing , GengYanSheng , HeYongWei
2015, 6(4):479-484. DOI: 10.16615/j.cnki.1674-8190.2015.04.013
Abstract:The article analyzed the differences between EASA and CAAC which demand on the design assurance system. And according to the aviation airworthiness regulation of the two authorities,the paper discriminated the elements included in the three functions which the design assurance system required. Finally, put forward some considerations for establishing the civil aircraft design assurance system .
2015, 6(4):485-489. DOI: DOI:10.16615/j.cnki.1674-8190.2015.04.014
Abstract:Mass distribution and C.G. of aircraft is one of the most important factors on landing gear and airframe ground loads. Among of them, the payload has the significant influence. In service, there are thousands of payload distributions. In order not to miss the critical load cases and decrease the loads engineer’s workload during fuselage loads analysis, the fuselage loads with different payload distributions were analyzed. The analysis results showed that the maximum payload condition will produce the critical fuselage vertical shear and bending moment.Therefore, for fuselage loads analysis, the maximum payload condition must be considered, and there is no need to consider the maximum fuel condition. This conclusion will provide the data reference for the future pointed fuselage loads analysis of civil aircraft
2015, 6(4):490-494. DOI: 10.16615/j.cnki.1674-8190.2015.04.015
Abstract:In order to support the scheme demonstration of widebody jetliner engine and the further research on geared turbofan, this paper focus on the Fan Drive Gear System conceptual design. The FDGS of star gear configuration consists of five branches which are of herringbone gears. It also has several features as follow. The sun gear is floating while using spine to transmit torque. The planetary gears are of integrated gear/bearing using single row spherical roller bearing. The ring gears are flexible mounted using friction to transmit torque. With the conceptual design, several technical difficulties are analyzed for further research such as transmission efficiency, load sharing, mounting structures, tooth surface modification and system dynamic.
Guo Fazhan , Zou He , Liu Zhirong , Zhu Rui
2015, 6(4):495-501. DOI: 10.16615/j.cnki.1674-8190.2015.04.016
Abstract:The rapid development of China's civil aviation transportation industry promotes the growth of civil aviation maintenance industry. This paper reviews the development mode of aircraft maintenance organization, analyzes the current situation based on Chinese characteristics. Then the paper prospects the trend of the development , indicating that the layout of the development is expanding to the central and western regions and the enterprises is facing the challenge of upgrade. And Finally the paper focuses on the problem of talent training, pointing out the the problem of colleges and universities, enterprises and training institutions and providing suggestions.
zhangzhao , xiaoyingchun , wangqian , zhengjianjun
2015, 6(4):502-506. DOI: 10.16615/j.cnki.1674-8190.2015.04.017
Abstract:This issue is to figure out the feature of AE signals ,which are produced by the cracks in Titanium Alloy of TC18,when the crack gives its birth,and grows until when the TC18 sample is broken. TC18 samples and fatigue test are designed , and AE signals are acquired along the test . Make clear the feature parameters of time domain and frequency domain using parametric method . Give the reference comments of AE monitoring in Titanium Alloy of TC18 samples.
2015, 6(4):507-511. DOI: 10.16615/j.cnki.1674-8190.2015.04.018
Abstract:According to the requirements of Shipboard aircraft service environment and technology requirements, and combined with aerial wires and cables development status at home and abroad, This paper puts forward the selection scheme of wires and cables in shipboard aircraft, and analyses the rationality of the selection scheme.
Shu Xiuli , Dong Dayong , Dong Wenjun
2015, 6(4):512-518. DOI: 10.16615/j.cnki.1674-8190.2015.04.019
Abstract:Aircraft flight deck warning system plays a vital role in improving work efficiency of pilots and assuring flight safety. This paper mainly summarized design criteria of visual warning signals and design requirements of information coding, and expounded design criteria of color coding and warning signals in relevant requirements, which supplied relevant references for aircraft flight deck visual warning signals design.