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2008 Vol. 34, No. 10

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Modeling and simulation of fibre channel for avionics
Zhou Tianran, Song Liru, Xiong Huagang, Lin Qiang
2008, 34(10): 1117-1120.
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Airborne network is an important part of the avionics system. According to the data transmission demand of avionics system, modeling and simulation of mixed complex topology fibre channel (FC) network was studied. Terminal model and switch model which can compose networks with different topology were built, based on the analysis of FC protocol. The FC network simulation platform which fits for the environment of avionics based on the discrete events system simulation method was built, and method of evaluating performance index such as throughput, delay and real-time characteristics was provided. Errors between simulation result and real data are less then 10%, which verified the accuracy of the model. A case was analyzed by the simulation model, and a performance evaluation of the airborne FC network was given.
Conceptual design of cruise missile based on technology of modern design of experiment
Ma Ying, He Linshu, Duan Yong
2008, 34(10): 1121-1125.
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By taking skip trajectory air-to-surface missile as example, the application of modern design of experiment (DOE) technology, namely latinized nearly orthogonal hammersley sequence sampling (LNOHSS), in multidisciplinary design optimization (MDO) was studied. Design experiments were conducted using LNOHSS technology, sampling data was compared with the data of conventional latin hypercube sampling (LHS). Metamodels of exact disciplinary models were built based on support vector machine (SVM). The reliability of metamodel responses was checked by regression analysis of validate data set. The example system was optimized based on metamodels, the correctness of metamodels was validated by comparing optimal results with exact analysis. LNOHSS is a highly effective DOE technology. It provides better orthogonality and uniformity than conventional LHS. LNOHSS technology is of great application value to the MDO of complex systems.
New kind of DBL-CDMA spreading codes
Yang Xing, Yu Zheng, Li Daoben, Deng Shuangcheng
2008, 34(10): 1126-1129.
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A new class of dao ben lab code division multiple access (DBL-CDMA) spreading codes with zero correlation window (ZCW) was presented, which is constructed by making kronecker product of basic loose synchronous (LS) codes and special complex matrix which is constructed by Barker sequence and its phase rotation. The auto-correlation and cross-correlation function of these new codes were analyzed and some basic theorems and corollaries on these new codes were proved. In addition, the realization methods of these new codes were also discussed. Compared with the basic LS codes, the new DBL-CDMA access codes extend the minimum ZCW, increase the number of available access codes and the number of perfect complementary pair for a fixed code length. Moreover, only few side lobes of auto-correlation and cross-correlation function appear in few time shift axis in the same group. The computer simulation results verify the validity of the theoretical derivations.
Conceptual study on integrated design of magnetohydrodynamic bypass scramjet for a waverider-based hypersonic vehicle
Lü Haoyu, Lee Chunxuan, Cao Deyi
2008, 34(10): 1130-1134.
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A parametric study on the conceptual design methodology and optimization criteria for an integrated magnetohydrodynamic (MHD) bypass scramjet of a generic waverider-based hypersonic vehicle was performed. An integrated parametric design of an MHD controlled inlet and a built-in MHD generator was first provided using a quasi-one-dimensional MHD model, in conjunction with the theory of oblique shock. Taking the designed configuration as the baseline configuration, a numerical procedure based on a five-equation model associated with low magnetic Reynolds number MHD flow was utilized to simulate and optimize the integrated MHD controlled inlet. It was found that the minimum nonuniform flow parameter at the exit of the inlet channel might act as the criterion for the built-in generator to possess an optimal magnetic interaction parameter capable of improving the performance of the inlet effectively.
Storage life and reliability evaluation of microwave electronical product by SSADT
Li Xiaoyang, Jiang Tongmin, Huang Tao, Li Gengyu
2008, 34(10): 1135-1138.
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High storage reliability system requires the extremely high reliable assemblies over long periods of storage time. Within severe time and cost constraints, step stress accelerated degradation testing (SSADT) was utilized to evaluate storage reliability and life of microwave electronical assembly. Firstly, the assumptions of SSADT were given. On the basis of failure mode effect and criticality analysis(FMECA) and fault tree analysis(FTA) results of the microwave assembly, accelerated model was determined. Then, reliability evaluation model was generated combined with linear drift Brownian movement. By the independence increment property of linear drift Brownian movement, the maximum likelihood and regression analysis were used to evaluate the parameters of reliability model. In order to eliminate the effect of power cycle on storage reliability and life, degraded rate conversion method and converted function of linear drift Brownian movement was presented in light of GJB108-98. Engineering application validated that reasonable evaluated results could be obtained by the methodology proposed.
Effect of heptane-to-brim of pool distance on water mist fire suppression
Yang Lijun, Wang Xiangdong, Liao Shengjie, Yang Chunting
2008, 34(10): 1139-1142.
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The pool fire tests were conducted to evaluate the water mist system’s ability to extinguish relatively liquid fire. In order to investigate the heptane pool fire suppression with a water mist fire suppression system, a series of experiments were performed in an enclosed compartment of 4.6m×3.3m×4m(L W H)with variable distance of heptance-to-brim. Thermocouples and gas analyzer were used to measure the temperature and gas concentration in the flame. The effection of heptance-to-brim to the effectivity of water mist suppressing pan fire was gained, which provides corresponding experimental foundation for designing water mist system, establishing test standard and developing new product of water mist.
Design of nonlinear flight control law based on bifurcation tailoring
Chen Haibing, Zhang Shuguang, Fang Zhenping
2008, 34(10): 1143-1146.
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The global and continuous flight control law was designed via the bifurcation tailoring and eigenstructure assignment methods. Based on the equilibrium branches of aircraft flight dynamics, the feedforward control law was designed by utilizing the continuous method, by which the shape of the equilibrium branches was modified to make the output variables trace the input commands. The uncoupled gain-scheduled feedback control law was designed via the eigenstructure assignment technique to meet the requirement of flying qualities, and the equilibrium branches of the uncommand motion were tailored. Control bifurcation was analyzed for the feedforward open-loop control system and the feedback closed-loop control system. The control law design and computer simulation for a static unstable aircraft were presented to demonstrate that the unexpected bifurcation behaviors were restrained and the stable flight envelope was extended.
Effect of atmospheric scintillation on laser communication system by pseudo-non-diffracting beam
Li Meng, Wang Zhongyu, Gao Xiaoying
2008, 34(10): 1147-1150.
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In pseudo-non-diffracting beam communication system, the intensity variance on the receiver is brought by atmospheric turbulence, and thus the bit-error rate(BER) of the communication system could be effected. Ignoring other noises in the system, the relationship between BER with the refractive index structure parameter, communication distance and wavelength was deducted based on the distribution of intensity variance. The changing law of BER along with index structure parameter was researched through computer simulation, the impact of communication distance and wavelength on BER was discussed and the allowed range of communication distance was determinated under BER criterion of 10-9. It is indicated that the atmospheric turbulence-s effect to BER can be weaken by choosing appropriate weather and sunlight condition, decreasing communication distance and using laser with longer wavelength.
Frequency-dependent transformation matrices of phase-domain transmission line models
Fan Shengtao, Li Xiaqing, Li Yunhua
2008, 34(10): 1151-1154.
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A new algorithm for evaluating the frequency-dependent transformation matrices as smooth functions of frequency is presented. The new algorithm firstly calculates the frequency-dependent transformation matrices at each frequency point using conventional algorithms; a special smoothing procedure based on optimization is then used to eliminate the inevitable jumps. The validity of the algorithm is verified with a double-circuit untransposed three-phase transmission line example. To analysis how the characteristic admittance matrices and the propagation matrices are affected by the jumps of the elements in the frequency-dependent transformation matrices, the smooth frequency-dependent transformation matrices are used to calculate the characteristic admittance matrices and the propagation matrices, which shows that the characteristic admittance is sensitive to the jumps while the propagation matrices not.
Adaptive time delay estimation of distributed fiber optic perturbation sensor
Luo Guangming, Zhang Chunxi, Ma Zongfeng, Lin Wentai
2008, 34(10): 1155-1158.
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Considering the defects of shorter monitoring distance, the sensitiveness to electromagnetic interference and higher cost of maintenance in traditional security guard system, a novel distributed fiber optic perturbation sensor was proposed. Composed of the dual M-Z (Mach-Zehnder) interferometers of all fiber instruments, the sensor proposed can locate the position of the intruder and send out the alarm by the sensitiveness to perturbation of fibers. The experiments show that the signal of intruder-s perturbation is band-limited. According to the perturbation signal characteristics of the sensor, the self adaptive time delay estimation using the LMS (least mean square) algorithm was studied, and the performance of the self adaptive algorithm was provided. The experiment results show that the self adaptive algorithm can be applicable for locating on real time with the locating error less than 200 meters. The sensor designed has been successfully applied in security guard system in several areas.
Error analysis system of turbine blade based on CAD model
Xi Ping, Sun Xiaoxia
2008, 34(10): 1159-1162.
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The error analysis of blade surface is very important during the process of turbine blade manufacture. Firstly, key technologies of surface inspection were studied, and the crucial parameters automation extraction algorithm for blade section from measured data was proposed. Next, the registration method between measured data and computer aided design (CAD) model was given. Meanwhile, several indexes of evaluation for blade were put forward, such as profile error, angularity error, camber error and twist error. Finally, the error analysis system of turbine blade was developed based on UG. Successful experimental results show that this system can improve the efficiency and quality of blade surface inspection.
Design of MAS-Based AmI system and implementation of its identity-aware agent
He Jian, Zhang Yong, Hou Yibin, Huang Zhangqin
2008, 34(10): 1163-1167.
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The conception of ambient intelligence (AmI)was introduced firstly, and the data flow of the context-aware on the AmI environment was analyzed as well, so multi-agent system based(namely MAS-Based) architecture of AmI system was proposed. Meanwhile, an AmI experimental system (namely AmI-Space) built on the MAS-Based architecture was expounded, and the identity-aware agent being part of the AmI-Space was described. It is demonstrated by practice that the MAS-Based architecture was fit for the characters of modularization, distribution, scalability and complexity owned by the AmI computing units, and the identity-aware agent combining advantages of Bluetooth Ad-hoc network and Ethernet can automatically sense the user identity, and a kind of natural human computer interface for AmI system was provided.
Simulation of ejection seat-s static amenity
Huang Jiayang, Qiu Yifen, Yan Yinxue, Jiang Nan
2008, 34(10): 1168-1171.
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Aiming at the problems in the amenity of the ejection seat,based on the Poser software,the 3D static manikins of chinese male pilots was established,insuring the veracity of the main parts of the human body.Secondly,the ejection seat model was imported to 3Dmax,and established a ejection seat-control equipment model,according to geometry size of plane cabin and control equipment.At last,a ejection seat-pilot-control equipment system model was established by utilizing the theory means of ergonomics.By taking a movement simulation and analysis for the pilot on the platform,some amenity factors was discussed and the optimization designing method was provided.The platform can increase the degree of standardization and generalization of the amenity study,because of the veracity and adjustment of the parameter.
Impact of lower reaction on high aerodynamic load transonic fan inlet stage
Song Xizhen, Zhou Sheng, Li Qiushi
2008, 34(10): 1172-1176.
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Lower reaction was concluded to be a necessary consequence of an increased aerodynamic load of a transonic fan/compressor inlet stage. Through the definitions of aerodynamic load coefficient and reaction, the rule of reaction changing with aerodynamic load coefficient was acquired, and two critical values of aerodynamic load coefficient were given. Based on a successfully designed and tested single stage high load fan, four transonic fan rotor designs were compared through numerical simulation. It was found that with the increase of aerodynamic load coefficient, the distribution of aerodynamic parameters in rotor hub region was changed remarkably. Transonic incoming flow to the stator is determined to be a problem in the design of a high aerodynamic load transonic fan inlet stage. Through discussions, it-s considered that the problem of transonic incoming flow to the stator could be solved by existing design methods. The best design of the single stage fan was picked up, with its aerodynamic load coefficient reached 0.53, and its 3D viscous flow field was analyzed.
2-D parallel memory architecture for video processor
Zhu Di, Shen Gongxun
2008, 34(10): 1177-1181.
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Video codec has a very high computation complexity and features intensive vector accesses to memory. A 2-D parallel memory scheme based on linear skewing scheme was proposed. The memory scheme can be combined with simple instruction multiple data (SIMD) vector processor to address the computation challenge of video. The address generation logic and scheme-s micro architecture were analyzed. The scheme uses a data rotation unit to permute data element to form a vector. This method simplified data permutation network which is the bottleneck of most parallel memory schemes. The performance difference between parallel memory and traditional memory were also compared. The kernel module of H.264/AVC such as motion estimation, de-blocking filter and interpolation were investigated based on the proposed memory scheme.
Application of improved genetic algorithms in aircraft conceptual parameter optimization design
Qiu Zhiping, Zhang Yuxing
2008, 34(10): 1182-1185.
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Based on the multi-objective optimization problems in the aircraft conceptual parameter design, improved multi-objective genetic algorithms were proposed. The "Pareto front "of Multi-objective optimization (MO) was tried to seek by using inherent parallelism of genetic algorithms (GA) while emphasizing the Pareto optimal conception. Different improved genetic algorithms were applied to a same two-objective optimization arterial airliner conceptual parameter optimization design, where both the ratio of lift to drag in cruise and the useful load fraction were asked to be maximized. Through general analysis and comparison to solutions of different algorithms, it can conclude that the Pareto optimal results of the non-dominated sorting genetic algorithm(NSGA) are better than the improved vector-evaluated genetic algorithm(VEGA) and the random-weight genetic algorithm(RWGA), while the results of VEGA and RWGA are equal.
Performance parameters analysis and design of space cable-strut deployable articulated mast
Guo Hongwei, Liu Rongqiang, Deng Zongquan
2008, 34(10): 1186-1190.
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The primary performance parameters of the space cable-strut deployable articulated mast was derived which can evaluate the space cable-strut deployable articulated mast performance. The relationship between primary performance parameters and geometrical feature parameters of space cable-strut deployable articulated mast was analyzed and studied. The expressions of line density, packaging efficiency, bending stiffness and bending strength of the mast were derived. The influence of mast-s material character to its performance parameters was analyzed. The stability problem of space cable-strut deployable articulated mast was discussed, and the condition of local instability and global instability was analyzed. The mast was designed based on two constraints modes of bending strength constraint and bending strength with bending stiffness constraints. The relation equations of geometrical parameters and line density of the mast relate with its bending strength and bending stiffness were established. The design results were analyzed and compared with the parameters of the American able deployable articulated mast.
Numerical simulation of cavitation flow field for under water projectile
Cao Damin, Xu Xu
2008, 34(10): 1191-1194.
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A homo-equilibrium model was used to compute the hydrodynamic cavitation flow field over an axisymmetric projectile by solving the incompressible Navier-Stokes equations. The governing equations were resolved in a finite volume manner, the convective fluxes were treated by an upwind differencing scheme and the time was integrated using the LU-SGS approach. A mass transfer model introduced by Kunz was implemented in a viscous Navier-Stokes solver. A preconditioning method was used for the low-speed computations and the point implicit method for the mass transfer source terms. The computations were performed for the cavitation flow of an axisymmetric projectile under the Reynold number of 136000 and the cavitation number of 0.1, 0.2 and 0.3. The wall pressure coefficients on the axisymmetric projectile were obtained and compared with experimental data, the agreements were excellent. And then, the super-cavitation phenomena were studied for σ＝0.2,0.1, 0.06, and the super-cavitation flow-field was obtained for cavitation number σ＝0.06.
CFD study of fluid flow in an all-glass evacuated tube solar water heater
Ai Ning, Fan Jianhua, Li Yumin
2008, 34(10): 1195-1199.
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The all-glass evacuated tube solar water heater is one of the most widely used solar thermal technologies. The aim of the paper is to investigate fluid flow in the solar water heater by means of the computational fluid dynamics (CFD). The investigation was carried out with a focus on the convective heat transfer in the tube. The buoyancy induced flow circulation in different parts of the tube was analyzed. It is shown that fluid flow becomes stochastic and turbulent if fluid temperature is high enough. The flow instability leads to mixing of the warm uprising flow and the cold downward flow, which decreases efficiency of the heat exchange process. A baffle in the tube can prevent the flow instability and secure the flow circulation in the tube. The results of the investigation provide a helpful guidance for further investigation of the mechanism of heat transfer processes and a reference for future system optimization.
Fast diagnosis algorithm for interconnect faults on system buses
Zhong Bo, Meng Xiaofeng, Ji Hong, Chen Xiaomei
2008, 34(10): 1200-1203.
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The interconnect test and fault diagnosis for system buses are important to the manufacturing and maintenance of electronic products. The previous test algorithms which are proposed in literatures have some problems, such as existing redundant test vectors and having long test time etc. An adaptive and fast diagnosis algorithm was proposed according to the analysis of the interconnect-fault syndromes on system buses. The test process was divided into two phases. In the first phase, the short and stuck-at faults on supernets were diagnosed and then the supernets were divided into several groups according to the diagnosed short faults. In the second phase, the "parallel walking 1" test vectors were applied to the grouped supernets to diagnose the open faults. The results show that the proposed algorithm can support maximal diagnosis, remove the redundant test vectors, shorten the test time and realize fast diagnosis.
Numerical simulations of flame tube cooling structure with multi-jet holes
Li Zhiqiang, Tian Tao, Chen Qin
2008, 34(10): 1204-1209.
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The numerical simulation was used to study the film cooling effectiveness of plate with multi-inclined jet hole. The effect of the blowing ratio, oblique angle of the hole, array way of the hole, compound angle and shape of jet holes was investigated for increasing cooling efficiency. The computational results show that the blowing ratio and the oblique angle of the hole have important influence for the cooling efficiency. With the increase of the blowing ratio, the cooling efficiency increases, but the trend of increase is decreasing. And with the decrease of the oblique angle of the hole, the high cooling efficiency can be gained. The array way of the holes has a certain effect on the cooling efficiency, i.e. long diamond distribution is better than the regular diamond distribution. Also, the computational results show the introduction of the hole offset angle in the y direction is unfavorable for cooling. In addition, compared with cylinder holes, when the holes with the cone contractive entrance and the cone outspread exit are used, it is found that the cooling efficiency can be improved with low blowing ratio, and the cooling efficiency is inferior with high blowing ratio.
Topology of power system reliability in more electric aircraft
Bian Xiangnan, Zhou Yuying, Ma Qishuang
2008, 34(10): 1210-1213.
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The topological structure is one of the key factors affecting the reliability performance of the electrical power system (EPS) in more electric aircraft (MEA). A topology analysis method was adopted to build a universal algorithm of reliability evaluation. Qualitative results could be obtained through this method. Faults tolerance ability of EPS in MEA was focused in the analysis process. Quantitative indices was obtained through euclideandistance and entropy calculation of the analysis results in the evaluation process. Based on this reliability evaluation platform, qualitative analysis and quantitative indices calculation of different aircraft topological configurations were experienced using a sample system data. Result shows that the reliability level of redundancy power network is better than others and it is the basical configuration prototype of future aircraft power networks.
Design of wide-angle infinity display equipment of airplane simulator
Guan Yingzi
2008, 34(10): 1214-1216.
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Wide-angle infinity display equipment (WIDE) is an important part of airplane simulator which directly affects the performance of airplane simulator. Surface shape of collimating mirror and back-projection screen in WIDE is a key factor which decides imaging quality. Therefore, the design of collimating mirror and back-projection screen turns into a key problem in WIDE development. Aiming at the technical requirement of WIDE of airplane simulator for two-seater airplanes, the condition of compensating astigmation of zero field of view was discussed, the surface of collimating mirror was designed to be bracelet form to ensure the astigmation of zero field of view would be zero, and determine the size of collimating mirror. On the principle for minimum disc of confusion, shape and location of back-projection screen was obtained by inverse ray tracing, finally the collimation precision calculated. The WIDE designed could provide 180 horizontal field angle and 45 vertical field angle, and is already used in flight training.
Corrosion failure of aluminum alloy parts on airplane used in marine environment
Huang Lingcai, Gu An, Liu Huicong, Jiang Tongmin
2008, 34(10): 1217-1221.
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Corrosion of aluminum alloy parts on airplane used in marine environment for tour was discussed. Along with the research of microcosmic image and corrosion product component of aluminum alloy parts on airplane, and considering the environmental condition used for the airplane, corrosion style, corrosion process and corrosion mechanism of aluminum alloy parts were researched. Results show that corrosion cause for aluminum alloy parts is residual seawater including chlorine ion from marine environment in the annular and plane clearance between constructional rivet and airplane parts, and insufficient protection for surface of airplane parts. Pit immersed firstly on the surface of aluminum alloy parts, and subsequently, intergranular corrosion and exfoliation occurred, stress due to the corrosion production accelerated delamination and flake away. Some suggestions were given to improve the anti-corrosion ability for aluminum alloy parts used on airplane, which include eliminating and filling in the constructional clearance.
Product structure formal modeling in product development
Sun Fei, Tang Xiaoqing, Duan Guijiang
2008, 34(10): 1222-1227.
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Based on the analysis of product structure properties and their relationships throughout product developing process, a formal product structure model was proposed to satisfy application requirements of dynamic structure configuration, dynamic tasks collaboration, dynamic objectives solution and dynamic state tracking. Considering the performance and characteristics of product developing activities in time domain, time domain definition of product structure was presented on the basis of which the product structure model extended in time domain was established. By analyzing the mapping relationship between product state and time domain performance of product developing activities, product state tracing scheme and related arithmetic based on time section were provided, which would play an important part during the process of putting the product structure model into practice. Finally, practicability and validity of the formal product structure model and its related theoretics were demonstrated by simulating a product state tracing instance.
Fast inference algorithm of launching decision-making expert system for launch vehicle
Li Qingdong, Liu Chengrui, Ren Zhang
2008, 34(10): 1228-1231.
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The launching decision-making system is an expert system which can diagnose the faults of the launch vehicle during the pre-launch testing and give the auxiliary repair strategy and launch decision. In order to achieve the quick fault diagnosis, the launching decision-making expert system should use a fast inference algorithm because there are massive test data need to be processed and the time for diagnosis is quite short. Therefore, a fast inference algorithm including the fact-matching and rule-matching was presented. The fact-matching network was borrowed ideas from the rete algorithm. And the rule-matching network was performed based on the vectors calculation. Finally, a fast inference algorithm suitable for pre-launch FDD (fault detection and diagnosis) of launch vehicle was given. The presented algorithm has been applied in a distributed FDD expert system for a real of launch vehicle. Preliminary results indicate that the algorithm reasons more quickly and more accurately with less system resource consumption, and can meet the real-time requirements.
Multi attribute evaluation method for missile weapon system effectiveness based on WGA operator
Zhou Wei, Xia Guoping, Yan Ning
2008, 34(10): 1232-1235.
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The index system and model of missile weapon system effectiveness evaluation were constructed. In view of complexity, synthesis and uncertainty of missile weapon system effectiveness, analytical hierarchy process (AHP) and weighted vector methods were combined, a multi-purpose synthetic evaluation method of missile weapon system effectiveness based on weighted geometric average (WGA ) operator and combination weight geometric average (CWGA ) was proposed. The evaluation indexes were divided into single effectiveness, system effectiveness and synthetic effectiveness. To obtain evaluation information weighted coefficient of each index was calculated by using AHP.Attribute values were grouped by WGA and CWGA operators, in order to obtain synthetic attribute values of system and determine optimal plane, and then to solve synthetic evaluate problem of missile weapon system effectiveness. A computing example indicates this method is an effective method for effectiveness evaluation for missile weapon system.
Complexity statistical characteristics for Ad hoc network based on random waypoint model
Tong Chao, Long Xiang, Gao Xiaopeng
2008, 34(10): 1236-1242.
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Complex network theory can be applied in the context of Ad hoc network topology characteristics. Firstly complex network structure statistical characteristics and random waypoint model were introduced. Secondly the degree distribution and clustering coefficient of Ad hoc network based on random waypoint model were theoretically analyzed. After simulation test generated Ad hoc network mobile scenes based on the random waypoint model, the complex statistical characteristics such as average path length, clustering coefficient and degree under those scenes were gained. Finally by analyzing the simulation test data, these questions whether Ad hoc network have small-world effect or not, whether Ad hoc network is scale free or not and how about the degree distribution of Ad hoc network were definitely answered.

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