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2013 Vol. 39, No. 8

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Solution of minimum bounding box of scattered points based on genetic algorithm
Sun Dianzhu, Shi Yang, Liu Huadong, Li Yanrui
2013, 39(8): 995-998.
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An algorithm of minimum bounding box combining genetic algorithm with O'Rourke's algorithm was proposed, which regarded the volume function in O'Rourke's algorithm as the objective function and used the evolutionary factors to guide the searching directions. Through the process of the population's iterative generation, this algorithm narrowed the search area and the volume error. When the iterative process was over, the minimum bounding box was obtained by decoding the optimal individuals. The experimental results show that the algorithm can improve algorithmic efficiency and satisfy the volume accuracy simultaneously. The algorithm can deal with sorts of problems related to minimum bounding box fast solving of complex scattered point cloud.
Dynamic analysis methods of variable-mass Euler beam under longitudinal overload
Xing Yufeng, Xie Ke, Pan Zhongwen
2013, 39(8): 999-1003,1061.
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Overload is the real environment of launch vehicles. The variable-coefficient transverse differential equation for the free vibration of Euler beam under longitudinal overload was derived on the basis of the Hamiltonian principle. For the variable-coefficient dynamic system, the existence of eigensolutions satisfying the orthogonal conditions of mass and stiffness was proved, and the asymmetry of such eigenfunction was revealed. A modified Euler symplectic midpoint difference method and a modified mode superposition method were employed to solve the equation of variable-mass systems. The numerical results of the two methods agree well, and validate the correctness of present theory and feasibility of the two methods.
Intuitionistic fuzzy manufacture knowledge-driven robust tolerance design
Tan Changbai, Hou Dongxu, Wei Wei, Fu Rui
2013, 39(8): 1004-1010.
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Motivated by fuzziness and uncertainty of manufacture factors in their expression, measurement and effects on the production cost, a methodology of intuitionistic fuzzy manufacture knowledge-driven robust tolerance design was developed systematically based on the intuitionistic fuzzy set and robust design theories. An intuitionistic fuzzy manufacture knowledge set was established according to such five aspects as the values of equipments, the machinabilities of product, the process features, the product features and the technical skills of worker. The constitution and level division of every knowledge subset was also discussed. A system of evaluating goals of manufacturing cost involving the target layer, the rule layer and the knowledge layer was developed, and an intuitionistic fuzzy comprehensive evaluation algorithm was used to calculate the manufacture cost factor φ. This method is more comply with the human logic compared with the traditional fuzzy evaluation. A fuzzy robust tolerance optimization model was established combining a cost-tolerance model with a proposed fuzzy quality loss function. Complying with the DFM concept, this methodology considers a comprehensive effect of various manufacturing factors on tolerance design. A case study on the tolerance optimization of certain aerospace fuel tank illustrates the feasibility, flexibility and robustness of the proposed approach.
Design and analysis of four-dimensional force-measurement based on one-dimensional sensors
Liang Jianhong, Luan Yubao, Wang Tianmiao, Zhang Qian
2013, 39(8): 1011-1015.
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A four-dimensional (lift, roll moment, pitch moment and yaw moment) test platform was designed by using one-dimensional force/torque sensors. The multi-component coupling error problem was solved by putting three force sensors in parallel and using universal joints as connectors. Two force moments and one force can be accurately calculated from the force measurement of the three sensors. The measurement accuracy of the multi-axis sensor was improved by the decoupling matrix. Moreover, such structure is easy to assemble and disassemble. The feasibility was verified by comparing with the input loads in simulations. The horizontal error caused by the installation error of the sensor is within 0.5%. The effect of the measurement error to the system error was also analyzed.
Performance evaluation of a terrain-aided navigation system under different accuracy of sensor
Zhao Long, Yan Tingjun
2013, 39(8): 1016-1019.
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In order to select the type of the sensor, improve the terrain-aided navigation(TAN) algorithm, and do research on the reliability of the TAN system, the influence of the sensor's accuracy on the match probability was studied in the TAN. Based on different terrain, the factors that impact on match probability were analyzed, which are barometer error, radar altimeter error, velocity error, and heading angle error. The error range of sensors was determined by simulation computing in practical system. A simulation experimentation was implemented by using the digital map of hills, mountains and high mountains. The simulation results shows that TAN system allows the velocity error<2.2 m/s, the heading angle error<0.6° and standard deviation of altimeter noise<16.4 m, when the match probability is > 90%.
Corrosion properties of two kinds of hull steels welding joints in simulated marine environments
Yu Mei, Wang Ruiyang, Liu Jianhua, Li Songmei
2013, 39(8): 1020-1025.
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Corrosion properties of 10CrNi3MoV and 12MnSiNiCrMo welding joints were investigated by alternate immersion test, neutral salt spray test and constant load tensile stress corrosion test. These tests were designed to simulate circulatory soakage of seawater and marine atmosphere respectively. Dynamic polarization curves of the welding joints were tested too. Microstructures of the weld zone, heat affected zone and base metal were analyzed by metallographic technique. The results show that the weld zone is more liable to corrosion and more sensitive to fracture. The corrosion current density of weld zone is the biggest while the base metal is the smallest for both two welding joints. The corrosion resistance of 10CrNi3MoV is much better than 12MnSiNiCrMo. When the stress level is comparatively lower or higher, the welding joints of 12MnSiNiCrMo are more susceptible to stress corrosion cracking than 10CrNi3MoV. The corrosion current density of the welding joints of 12MnSiNiCrMo is much bigger than 10CrNi3MoV. Microstructure differences of different zones are the main reason. Proper amount of acicular ferrite maintains the obdurability corrosion resistance of base metal, but the resistance to corrosion and stress corrosion cracking is declined by superfluous ferrite in the weld zone.
Fault diagnosis expert system for electric power system of large-scale UAVs
Zhang Qinling, Guo Hong, Jiang Xu
2013, 39(8): 1026-1030.
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A fault diagnosis expert system of onboard power system and typical power distribution structure was designed for large-scale unmanned aerial vehicles (UAV), based on the test platform built with PXI bus and virtual instrument technology. By means of failure mode analysis and fault tree design, it is able to infer the cause of malfunction, locate fault location and propose solutions.In the system, a forward reasoning expert knowledge base on rule is built, in which a certainty factor was introduced to solve the non-exactinference in complex systems.Experiments of a UAV power supply system show that the proposed system can effectively improve the degree of intelligence of the test platform and meet the requirements of maintainability and supportability in the airborne system.
Transfer trajectory design between L2 in Sun-Earth system and L1 in Sun-Mars system
Lü Jing, Zhang Mingming, Zhang Yongwei
2013, 39(8): 1031-1036.
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The transfer trajectory bwtween L2 in the sun-earth system and L1 in the sun-mars system design using invariant manifold of the restricted three body problem is studied. Considering mars,earth and sun in the same plane, the four body problem of sun-mars-earth-spacecraft was divided into two three body problems, that were the three body problems of sun-earth-spacecraft and sun-mars-spacecraft. A Lyapunov orbit of Lagrange liberation point was designed with different correction method and Richardson three-order approximation solution as initial conditions. The transfer trajectory between Lyapunov orbit's invariant manifold of the two different restricted three body problems was designed with different correction method and the results was compared with the transfer trajectory between Halo orbit's invariant manifold of the two different restricted three body problems.The simulation shows that transfer trajectory design using the invariant manifold of Lyapunov orbit cost lower energy and shorter time of flight.
Numerical simulation of cure deformation of composite taper shell with thermal protection layer
Zhang Jikui, Ma Zhiyang, Li Xuemei, Cheng Xiaoquan
2013, 39(8): 1037-1041.
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A three-dimensional finite element model was developed to simulate and predict the cure deformation during the winding processing of a composite taper shell with thermal protection layers. According to the results of numerical simulation, the first cause of the shell's cure deformation was the thermal expansion coefficient difference between protection material and structural material which lay on outer layers and inner layers respectively. Meanwhile, this cure deformation can be controlled effectively by adding the middle layer between outer layers and inner layers, which reduced about 20% deformation by using nitrile rubber as the middle layer's material. The effects of other influence factors were also discussed: cure deformation was increased by improving the middle layer's modulus and decreased slightly by increasing the middle layer's thickness; the relief of winding tension, to some degree, had an impact on deformation, and larger tension leads to higher deformation.
Collaborative optimization of hypersonic vehicle based on surrogate model
Ma Shuwei, Du Bin, Chen Wanchun
2013, 39(8): 1042-1047.
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The multidisciplinary models of hypersonic vehicle which similar to the X-51A were built, including configuration, aerodynamics, propulsion, mass, heat and trajectory. The collaborative optimization (CO) method which is one of the multidisciplinary design optimization (MDO) method was used, the surrogate models of two subsystem optimizers and trajectory model were built to replace the real models which are time-consuming in the process. Meanwhile, multidisciplinary feasible (MDF) method was used to calculate for comparison. The results show that both the optimization results are basically the same, the mass of the vehicle is 15.2% lower and the range is 63.5% higher than the initial vehicle after optimization,and the computational efficiency has also been greatly improved by using the surrogate models. The validity of the CO based on surrogate model applying to hypersonic vehicle design is verified.
Multivariable model reference adaptive control with application to flight control
Jiang Xu, Zhang Qinling
2013, 39(8): 1048-1052.
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The problem of multivariable model reference adaptive control and its application to flight control were discussed. A model reference adaptive control scheme was proposed for multivariable linear time-invariant systems with arbitrary relative degrees. Based on the SDU factorization, it is only required that the signs of the leading principal minors of the high frequency gain matrix are known, which considerably relaxes the restrictions on the high frequency gain matrix. By constructing a proper Lyapunov function, it is proved that the closed-loop system is globally stable and the tracking error converges to zero asymptotically. The proposed scheme is illustrated to be effective though an application to a flight control problem.
Investigation of heat transfer enhancement of short pin fins in hot air anti-icing system
Bu Xueqin, Chen Yuchen, Lin Guiping, Peng Long
2013, 39(8): 1053-1057.
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Hot air ice protection is one of the aircraft used anti-icing technology. In order to increase the anti-icing efficiency of the hot air anti-icing system, the use of short pin fins were proposed to enhance the heat transfer. The effect on heat transfer enhancement and flow resistance with different structure of the pin fins in double skin anti icing channel were investigated by using the computational fluid dynamics (CFD) method, mainly including the ratio of the pin height to diameter, pin fins array type and the channel height. Research results show that the addition of the pins especially staggered pin fins could induce more heat transfer enhancement but also greater flow resistance. And when the channel height was less than 1mm, the heat transfer increased not obviously, indicating that the narrow double skin anti-icing channel do not need to add pin fins to enhance heat transfer performance. The results can provide theoretical guidance to the design of the double skin channel in the hot air ice protection system.
Compact MMW dual-polarized array antenna
Zhai Yu, Su Donglin
2013, 39(8): 1058-1061.
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A compact dual-polarized millimeter wave(MMW) microstrip array antenna was designed. Firstly, the antenna element was designed. The antenna element was fed by coplanar microstrip line and coupling slot. The high polarized-isolation could be obtained by the mixed feed points and reversed phase technology. The antenna array was designed by shunt fed. Finally, this antenna array was fabricated and measured. The measured data shows that the antenna VSWR is less than 2.0 and the polarized-isolation is 35 dB. And the antenna gain of horizontal polarization beam is over 12 dB while that of vertical polarization beam is over 11.5 dB.
Operation model on dynamic allocation system of carrier aircraft
Yue Kuizhi, Sun Cong, Luo Mingqiang, Zhao Hongchao
2013, 39(8): 1062-1068.
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To predict the allocation of carrier aircraft in the carrier warship scientifically, the carrier aircraft transferring between flight deck, hangar and lift and the process of aircraft turnaround were studied based on the dynamic system theory.The stock and flow diagrams and mathematical model about dynamic allocation system with the character of complex time varying was established. The dynamic allocation system from Russian carrier aircraft was taken as an example, verified two dynamic allocation process with hanging and no hanging when the aircraft turn around. The study result shows that the operation model can predict every loop of dynamic allocation system of carrier aircraft, and provide the theoretical evidence and technical foundation for scheduling the aircraft dispatch in carrier warship.
Prediction of thermal expansion properties for composites by micromechanical analysis model
Li Jianfeng, Yan Ying
2013, 39(8): 1069-1073,1085.
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A micromechanics finite element method was used to predict the longitudinal and transverse coefficients of thermal expansion of the following six kinds of composites, T300/5208, P75/934, P75/CE339, C6000/PMR 15, HMS/Borosilicate, P100/2024 Al. The predictions and some other common analytical methods were compared with each other. With experimental data, the predicting accuracy of all these analysis methods was investigated. In all of these methods, the predictions for the longitudinal coefficients of thermal expansion of composites have good agreement with experimental values. However, large discrepancies exist for the transverse coefficients of thermal expansion. The predictions of the Rosen and Hashin(RH) method and micromechanical finite element analysis model are better fit for the experimental values than other analytical methods, and then verify the reliability of the micromechanics finite element method. In addition, the response of the coefficients of thermal expansion for the fiber volume fraction of the six kinds of composites was established by using micromechanics finite element method, the influence of the property ratios of fiber and matrix on the coefficients of thermal expansion was obtained. The results provide the technical foundation for the application of advanced composite materials in aerospace structures.
Protection against atomic oxygen erosion of oxide coatings for spacecraft materials
Zhang Wen, Yi Min, Shen Zhigang, Zhao Xiaohu
2013, 39(8): 1074-1078.
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To improve the atomic oxygen resistance, TiO2 and SiO2 coatings were deposited on polyimide (Kapton), a common material of spacecrafts using magnetron sputtering. The technic of depositing coating was optimized by selecting the experimental material and parameters to overcome the disadvantage of cracking. The atomic oxygen effect experiments were carried out. The results show that the mass loss of Kapton decreases by two orders of magnitude after depositing coatings. In addition, surfaces of coated Kapton change little and display low tendency of cracking. The thermal expansion coefficient of TiO2 is closer to that of Kapton, so TiO2 can provide better protection comparing with SiO2.
Interval analysis and optimization for free vibration of all-composite lattice truss core sandwich beam
Xu Menghui, Qiu Zhiping
2013, 39(8): 1079-1085.
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Considering the uncertainties in composite materials, free vibration of all-composite lattice truss core sandwich beam was studied. By expressing the uncertain parameters in the form of interval vector, a high-accurate collocation interval analysis method, which requires the intervals rather than probability distribution functions of uncertainties, was proposed to calculate the natural frequency of all-composite lattice truss core sandwich beam with uncertain-but-bounded parameters and based on which interval optimization was accomplished. A feasible way for the design of novel composite materials with serious nonlinear phenomena was provided. Compared with the probabilistic analysis method, the results demonstrate the feasibility of interval analysis method and interval optimization method is of more engineering significance than deterministic optimization technique in the design of composite structures by fully considering the potential negative impact from uncertainties.
Attention allocation modeling under multi-factor condition
Wu Xu, Wanyan Xiaoru, Zhuang Damin
2013, 39(8): 1086-1090.
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To investigate pilot attention allocation, subjective expectancy utility theory and salient-expectancy-effort-value (SEEV) model were applied to establish a forecast model. Based on recent study, the model was consisted of information importance, occurring probability, salient and effort which represented for the both methods of information processing. In order to validate the model, 16 subjects performed an instrument supervision task under different priority and display usage conditions, and fixation distribution was recorded as evaluation index. The subjects were asked to monitor the information targets presented on the head-up display simulation interface and respond to abnormal information by pressing the corresponding button on the keyboard. The experiment results revealed that the model accounted for 83% of the variance in visual attention allocation between conditions. The present study could provide ergonomics evidence with cockpit display interface design.
Design and analysis of a new kind of hydraulic active filter
Jing Huiqiang, Zhang Xiaoning, Li Yanfeng, Fu Yongling
2013, 39(8): 1091-1095.
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In view of the current hydraulic active filter of large volume, complex structure and other problems, a new type of hydraulic active pressure fluctuation filter (HAPFF) was present with simple structure and small volume. The method of computational fluid dynamics (CFD) was employed to investigate the pressure field distribution in time domain and three group data of Dm(excitation amplitude) and fm(excitation frequency) were involved. The results indicate that the performance of the HAPFF depends on Dm and fm, if they match the equivalent parameters of the original unstable flow rate, then the HAPFF perform well, which agree with the wave interference well. The calculation denotes that the peak-peak pressure value reduced to 0.25 MPa from 2.26 MPa when fm=525 Hz and Dm=0.05 mm (that is to say, the pressure fluctuation dropped to ±0.6% from ±5.38%), which verify the effectiveness of the proposed design.
Design parameters sensitivity analysis of aircraft survivability
Yang Zhe, Li Shulin, Zhou Li, Shi Xiaopeng
2013, 39(8): 1096-1101,1121.
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Since parameters sensitivity analysis can analyse the effects of design parameters on aircraft survivability more in-depth, the method of applying sensitivity analysis to aircraft survivability design was studied. The calculation model of aircraft survivability was established based on the model of aircraft susceptivity、vulnerability and combat capability. The parameters sensitivity analysis was divided into two cases of the modified design of the old aircraft and the program design of new aircraft, which provided the basis for the selection of parameters in the modified design and initial range reduction of design parameters in the program design. Simulation results show that the method is effective and feasible.
Numerical simulation of high altitude propeller’s aerodynamic characteristics and wind tunnel test
Wang Yufu, Liu Zhenguo, Tao Guoquan
2013, 39(8): 1102-1105.
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High altitude propeller was studied. The three-dimensional Navier-Stokes equations were used to simulate the complex flow around a high altitude propeller and its aerodynamic characteristics were analyzed, in which the k-ε turbulence model was used. In accordance with similarity criteria such as equal Reynolds number and equal advanced ratio, the scaled model test of high altitude propeller was carried out. The simulation results are in good agreement with test results. The feasibility of the numerical simulation method for aerodynamic characteristics calculation of high altitude propeller is proved, and provides reference basis for the design and test of high altitude propellers.
Gain scheduled output-feedback control of aircraft using switched polytopic system approach
Li Wei, Wang Qing, Dong Chaoyang
2013, 39(8): 1106-1110.
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As the flight envelope becomes wider, modern aircraft are suffering from ever severer parameter variations over the operating envelope. To cope with the stability and output-feedback stabilization problem, a novel modeling technique was introduced first, which was based on the switched polytopic system approach. Employing switching polytopic Lyapunov functions and the average dwell time method, the criterion was deduced for asymptotical stability of the aircraft dynamics across the envelope. The control synthesis method was also provided, by which one obtained a static output-feedback stabilizing controller with varying gains. The proposed method was applied to the full-envelope control law synthesis of the highly maneuverable vehicle. Simulation results show that the design method features low design conservation in that it alleviates the average-dwell-time constraint on the aircraft flight conditions. The signal jumping in traditional switching controllers can be avoided and the satisfactory transient response can be achieved by the resultant gain-scheduled controller.
Availability simulation assessment system of ground launched ballistic missile
Yang Jikun, Xu Tingxue, Han Zhao, Wang Haowei
2013, 39(8): 1111-1116.
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Significance of availability assessment of ground launched ballistic missile was proposed. An modeling and simulation framework was put forward on the basis of mission time Monte Carlo random discrete event dynamic systems(MTMC-RDEDS) model. And based on model reusing technology, the simulation assessment system frame and software hierarchy were designed, which has great model and knowledge base, modular design and open interfaces. The key simulation model was given and the algorithm to achieve system was explored, which refer to working state, maintain and support, statistical model and optimization model. The key technique of simulation system was discussed, including stochastic variable modeling, weapon system modeling, and simulation system reliability assessment. The ground launched ballistic missile simulation assessment system was developed using VC++ and related software, and a simulation example was given to verify the validity of the model and system. The agreement of the final computation results with the experimental data indicates this method could be used to estimate the system availability quickly and effectively at engineering analyses, the assessment system is validity and superiority, and provided an effective means for the availability evaluation.
Attitude normalization based line feature point cloud extraction approach
Li Wei, Li Xudong, Zhao Huijie, Zhang Ying
2013, 39(8): 1117-1121.
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Extracting the point cloud corresponding to the edges from point cloud of a part is a basic work in the part 3D reconstruction, also a key point of point cloud processing. The commonly used curvature based LFPC(line feature point cloud) extraction approach may have large errors in curve surface fitting and curvature estimation due to the arbitrary attitude of original point cloud and the way of curvature estimation. An attitude normalization based LFPC extraction approach is proposed. First the attitude normalization is accomplished by adjust the principle direction of the point cloud to the z axis, then, after the curve surface fitting, the main curvature with the maximal absolute value is treated as curvature, finally, the LFPC is obtained by applying a curvature threshold. Experiments on different models show that the proposed approach has better efficiency and is adaptive to different kinds of models.
Hemodynamic simulation of partial pressure suits under pressure
Yang Tao, Ding Li, Zhang Chunguang, Qin Zhifeng
2013, 39(8): 1122-1126.
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To explore the impact of pressure on human body's blood circulation and its variation by studying the variation of pilots' physiological parameters in their capstan partial pressure suits with the method of simulation, which can provide theoretical support for pilots' safety. According to the characteristics of the partial pressure suits, a hemodynamic model under pressure was established on the basis of Heldt orthostatic stress model. At the same time the correctness of the model were verified through the ground pressure experiments. The model can simulate the hemodynamic parameter of systemic side-tube partial pressure suit under pressure, concluding heart rate, mean arterial pressure, stroke volume and cardiac output. Then the simulative and experimental data in the parameter of mean arterial pressure, stroke volume and cardiac output were compared. The results agree well with the experimental results, and verify the validity of model. This model can effectively simulate the hemodynamic changes of partial pressure suits under pressure.
Improving the capability of k-ωSST turbulence model for predicting stall characteristics of airfoil
Wen Xiaoqing, Liu Yangwei, Fang Le, Lu Lipeng
2013, 39(8): 1127-1132.
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Two-dimensional numerical simulations of NREL airfoil S825 with k-ωSST turbulence model were conducted. For the k-ωSST turbulence model could not predict the airfoil aerodynamic performance accurately at stall conditions, the non-equilibrium turbulence transport nature was systematically analyzed. It was found that: the mis-predicting of the stall characteristics was due to the fact that the tradition turbulence model could not accurately predict the strongly non-equilibrium turbulence transport nature. Correcting the constant a1 or β∞* could improves obviously the capability of prediction stall characteristics of k-ω SST turbulence model,because by giving a more reasonable turbulence transport nature, the capability of k-ω SST model in capturing the non-equilibrium turbulence was improved notably.
Title homogenizing residual stress of heterogeneous component based on vibration stress relief
Xiao Changling, Chen Yunxia, Xu Dan
2013, 39(8): 1133-1136.
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The heterogeneous component inevitably produced non-homogenization residual stress during the assembly process. As time goes on, the residual stress decreased continuously and consequently resulted in non-homogenization stress relaxation. This phenomenon affected the long-term stability of the component. Meanwhile, the heterogeneous component was unsuited to be processed by thermal stress relief. For this phenomenon, finite element simulation was used. First, the heterogeneous component residual stress distribution was simulation. Second, the change of heterogeneous component residual stress was to study under natural stress relief. Final, the vibration frequency and amplitude were given through the modal and the harmonic response analysis, and the change of heterogeneous component residual stress under vibration stress relief was researched through the transient dynamic analysis. Simulation results show that residual stress achieves stable after one year under natural stress relief. While residual stress achieves stable in the initial few cycle under vibration stress relief. So comparatively analyzing the simulation results, it is shown that vibration stress relief based on plastic deformation theory is a fast effective to residual stress homogenization.

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