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2014 Vol. 40, No. 12

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Volume 40 Issue122014
2014 Year 40 Volume 12 Issue E-journal
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Requirement from maximum rate of climbing of aircraft service ceiling to turbocharged reciprocating engine
Xu Bin, Tan Longxing, Yang Shichun, Ji Fenzhu
2014, 40(12): 1643-1647. doi: 10.13700/j.bh.1001-5965.2013.0746
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A wide operating range of engine is of vital to the safety operation of aircraft, especially at service ceiling. Through the dynamic analysis of the matching process between the aircraft and power plant which is composed of the turbocharged reciprocating engine and propeller, quantitative performance requirement for engine from the service ceiling was proposed, which proved to associate with the operating range and surplus power of engine. The operating range can also be used to evaluate the matching result besides the design point performance. This means that the conditions of cruising should guarantee the engine power recovery to sea level. A calibrated simulation model was created by GT-power. Its operating range was obtained by simulation and the factors influencing operating range were analyzed in theory. The advice of matching turbochargers based on the wide operating range was given considering the safety. This process can also be used to verify the margin of adjustment at service ceiling to ensure the safety.
Optimal design for thermal insulation layers of energy-storage sodium-sulfur batteries
Zhang Jianping, Han Yi, Liu Yu, Zhu Qunzhi
2014, 40(12): 1648-1653. doi: 10.13700/j.bh.1001-5965.2013.0758
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In order to solve the problems of over large thickness, short life, poor reliability of non-vacuum thermal insulation structure for sodium-sulfur battery, the mathematical model was established by thermal conductivity theory of multi-level insulation layer structure, solid modeling and numerical simulation were done by finite element analysis software ANSYS, the impact of different thermal insulation materials on the actual performance was analyzed, and an optimal design by the actual test validation was proposed. The results indicate that the optimization design meets the design requirements, decreases the total thickness of thermal insulation structure by 37.5% by applying new thermal insulation materials, and then reduces the overall size and weight of the structure. Furthermore, the layout method of the thermal insulation materials arranged according to the material properties and thermal resistance was summarized, which ensures each material is safe and reliable under working conditions. Research results can provide technical references in design and optimization of the insulation structure for sodium-sulfur batteries and other devices in the future.
Effective multi-objective optimization for aerodynamic and stealthy performance of tactical missiles
Liu Li, Jiang Menglong, Long Teng, Wu Di, Huang Bo
2014, 40(12): 1654-1659. doi: 10.13700/j.bh.1001-5965.2013.0753
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A new effective multi-objective optimization method was employed to solve the aerodynamic and stealthy performance optimization of tactical missile problem. Physical programming was selected to translate the multi-objective problem into the single objective problem. Genetic algorithm (GA) was applied to carrying on the design space search. Variable selection and radial basis function (RBF) were contributed to reducing the design variable space dimension and the number of high fidelity model evaluations. Then, the aerodynamic and stealthy performance optimization of a quasi BGM-109 model was chosen as an example to deliver the whole optimization steps and verify the correctness of the method. The optimization task is to minimize the drag coefficient and the heading radar cross section (RCS) subject to the aerodynamic performance constraint, namely the lift coefficient has to be no less than the initial value. Through application to engineering case, the computational cost of the proposed method decreases by 83% compared to that of GA, while two methods has nearly identical performance.
Numerical analysis of influence factors on stability for dual-stage gas pressure reducing regulator
Sun Bing, Xu Qi, Chen Yang, Wei Lijun
2014, 40(12): 1660-1665. doi: 10.13700/j.bh.1001-5965.2014.0012
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A numerical model of a dual-stage gas pressure reducing regulator, which is used in an aircraft pressurization system, was established on the basis of finite volume transient model of single-stage gas pressure reducing regulator. A modularization simulation model was also set up for performance study of dual-stage pressure regulator. The influences of different structural parameters on the stability of the two regulators which have tiny structural differences were illustrated by a series of numerical simulation, and their results were compared and analyzed. According to practical needs, the sample variance of II-stage valve spool velocity was chosen as the stability index, numerical analysis was then conducted on the influence factors including the II-stage valve spool mass, the II-stage low-pressure cavity volume, the II-stage feedback cavity volume, and the II-stage diaphragm stiffness. Results show that designers can decrease the II-stage valve spool mass or increase the II-stage diaphragm stiffness to improve the stability of the regulator. The study can help designers to meet the engineering requirements with minimum expenditure.
MPC based static aeroelastic numerical method for high aspect ratio wing
Huang Wei, Lu Zhiliang, Tang Di, Guo Tongqing
2014, 40(12): 1666-1671. doi: 10.13700/j.bh.1001-5965.2014.0015
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The steady aerodynamic loads were calculated with N-S equations and the multi-block structured grid technique was used to improve the computational efficiency. A beam model was applied to a high aspect ratio wing, and its structural deformations were evaluated by the finite element method with or without geometry nonlinearity. A multi-point constrain (MPC) method was used for the information exchange between the aerodynamic loads calculations and the structure deformations calculations. The static aeroelasticity was further considered. By successive iterations between self-developed computational fluid dynamics (CFD) solver and NASTRAN computational structural dynamics (CSD) software based on the MPC interpolation method, a quick and accurate coupled CFD-CSD method was achieved for the nonlinear static aeroelastic problem. Obviously the present method is more accurate than the conventional flexibility approach only considering single-direction deformation. Numerical analysis of a high aspect ratio wing demonstrates that spanwise deformation would have certain influence on its static aeroelastic characteristics and that geometric nonlinearity has small effect on this common airliner wing.
Analysis on power line harmonic radiation in China space
Wu Jing, Zhang Chong, Fu Jingjing, Ma Qishuang
2014, 40(12): 1672-1677. doi: 10.13700/j.bh.1001-5965.2013.0759
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A method was studied to detect power line harmonic radiation (PLHR) events using electromagnetic field data of DEMETER satellite and the characteristics of PLHR events in China space were discussed. All the satellite electric field strength data in China space during the 6 years between 2005 and 2010 were analyzed by time-frequency analysis and Welch spectrum estimation method, with 151 PLHR events detected. Statistical analysis and typical examples were presented. The results show that the frequencies of PLHR events in China space are distributed between 1 000 and 4 500 Hz. Most spectral lines of them are odd times of 50 Hz, with frequency spacing of 50/100 Hz. PLHR events have some closely connections with the change and development of power grid, but have no relations with geomagnetic activities, and they appear seasonal differences and differences between day and night. The possible factors that affect PLHR detecting were presented in the end.
Foreign object debris detection for airport runway with video data
Chen Weishi, Li Jing
2014, 40(12): 1678-1684. doi: 10.13700/j.bh.1001-5965.2013.0762
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Foreign object debris (FOD) detection algorithm was proposed for airport runway with video data, including four steps of geometric adjustment, background subtraction, noise suppression and camouflage elimination. Firstly, geometric adjustment rejected the image change due to slight camera motion. In the step of background subtraction, the color vector information to each pixel was used for the establishment of the background model and its periodical update. For noise suppression and camouflage elimination, Markov random field and probability statistical model were established based on the information from the subtracted and original images, which reduced the false alarms and improved the detection rate. The algorithm was applied to two sets of live video images under different lighting conditions, with the FOD targets of different shapes and colors. The algorithm effectiveness was also approved by the tests on the airport ground-truth data.
Life cycle assessment of pneumatic and electric actuators based on Simapro
Zhang Yeming, Cai Maolin
2014, 40(12): 1685-1690. doi: 10.13700/j.bh.1001-5965.2013.0767
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In the similar mechanical performance and working condition cases,life cycle assessment (LCA) of three groups of pneumatic actuators and electric actuators was carried on in order to analyze the extent of environmental impact of the actuators. The main environmental impact assessment factors of pneumatic actuators and electric actuators were analyzed. And the scope of the study, system boundaries and time boundaries were determined for the LCA of two kinds of actuators. The main manufacturing process and components processing features of two kinds of actuators were summed up. Finally the evaluation framework establishment and data entry of two kinds of actuators were conducted with Simapro 7.1, and the LCA comparative analysis of two kinds of actuators was carried out with Eco-indicator 99. The result reveals that the resources impact accounts for about 50% of the overall environmental impact value of actuators, and the environmental impact of electric actuators is large than that of pneumatic actuators under the similar mechanical properties and working conditions of these actuators.
Numerical investigation about field characteristics of screen
Cong Chenghua, Liao Daxiong
2014, 40(12): 1691-1696. doi: 10.13700/j.bh.1001-5965.2014.0018
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There is no reasonable path to evaluate screen performance accurately based on conventional method, such as the experiential formula and engineering correlations technology. Computational fluid dynamics (CFD) with proper boundary conditions was used to find screen performance of different parameters including total pressure loss coefficient and control ability of turbulence intensity. Total pressure loss coefficient of the screen was obtained precisely using CFD with different open area ratio, Renault number, incidence angle, wires per inch, etc., especially, incidence angle equal to 30°-45°. Pressure and velocity after screen was pulsant when air flowed into the screen at certain incidence angle, and the disturbance would become weak after about 100d. The flow regime around the screen kept laminar when Re less than 40, the distance of disturbance about 50d, and that turbulence intensity was reduced on a large scale. With the increase of Re, the distance of disturbance increased to about 400d, the reduce factor of turbulence intensity became smaller than laminar regime significantly. Smaller is the open area ratio of screen before flow regime changed to instability state, bigger is reduce factor of turbulence intensity. Based on the details of numerical results, the instability most likely appears when openning to sectional area ratio less than 0.5. Total pressure loss coefficient and reduce factor of turbulence intensity increases at distinct rate with increase of wires per inch when open area ratio keeps constant. It is concluded that the optimal parameters of the screen can be obtained based on numerical results.
Geographic load aware routing algorithm for highly dynamic airborne networks
Liu Zhi, Xu Zhen
2014, 40(12): 1697-1701. doi: 10.13700/j.bh.1001-5965.2013.0747
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Due to the high mobility of the aerial vehicle nodes, dynamic changes of the topology structure and the time-varying node trajectories, highly dynamic airborne networks (HDAN) suffer problems such as low data delivery ratio, high data congestion potential and poor stability. In order to address these problems, a geographic load aware routing algorithm was presented. This proposed algorithm defines a new dynamic routing metric for the next hop selection, which is adaptive to the topology changes, and it also introduces relative velocity, which is intended to amend errors caused by simply considering geographic information. The algorithm also reduces the congestion ratio of the network, according to the queue information exchange between the neighbors which is used to indicate local load level. The simulations show that the proposed routing algorithm is capable of reducing both end-to-end delay and the probability of delivery loss, therefore it enhances the reliability of the data transmission.
Object recognition based on background attributes
Luo Jianwei, Jiang Zhiguo
2014, 40(12): 1702-1706. doi: 10.13700/j.bh.1001-5965.2013.0750
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Attribute is the semantic description of an image, which denotes the existence or absence of a semantic property of the image, and it can not only be shape, material, part, category or functionality of an object, but also be label or context of a scene. To improve the accuracy of object classification, considering that object categories are related to the background where they belong to, an approach for object recognition based on modeling background attributes and foreground object attributes was proposed. Each attribute of background and object was trained by a support vector machine (SVM) classifier, and the output value of each attribute classifier was concatenated to form a new feature, based on which the final SVM classifier was trained. 10 kinds of background attributes were manually annotated for each image. Compared to the traditional method, method only based on object attributes and other methods considering different concatenating schemes of background and object features, experiments on the a-Pascal dataset show that the proposed method outperforms the others by around 2%, and background attributes can benefit object recognition task.
Algorithm of asynchronous sensors bias estimation in networked targeting
Yong Xiaoju, Fang Yangwang, Zhang Dengfu, Diao Xinghua
2014, 40(12): 1707-1712. doi: 10.13700/j.bh.1001-5965.2013.0768
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Aimed at the problem that the algorithm of asynchronous sensors bias estimation cannot adapt to the maneuver targets, a novel algorithm based on the interpolation was researched. Firstly, the measurement was changed into synchronization data by using the time registration method. Then, the pseudo measurement equation could be obtained according to the time registration results. Be different from other algorithms of which the pseudo measurement, independent of target state, is obtained by getting a adding coefficient according to the target state vector and time of arrival (TOA), the depseudo measurement deigned has no relationship to the target state vector. Moreover, the derivation of the pseudo measurement according to the time registration results is also independent of the movement of target. So, the problem of asynchronous sensors bias estimation with maneuver targets can be solved by the algorithm proposed. The results of simulation show that the sensor bias could be exactly estimated when the target takes a snake maneuver.
Pilot visual attention allocation modeling based on spatial mapping
Wu Xu, Wanyan Xiaoru, Zhuang Damin
2014, 40(12): 1713-1718. doi: 10.13700/j.bh.1001-5965.2014.0001
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To investigate pilot visual attention allocation, salient-expectancy-effort-value (SEEV) model and multiple factor model were applied to introduce the concept of attention control space and resource allocation space. The former space described the influencing factors of attention allocation while the latter one depicted the attention resource allocated to certain area of interest. A new forecast mathematical model was established based on spatial mapping and calculated in the method of fuzzy analytic hierarchy process. In order to verify the effectiveness of the new model, sixteen subjects were recruited in an ergonomics experiment to perform an unusual attitude recovery task in a high fidelity flight simulator. As evaluation index of attention allocation, the fixation distribution of subjects was recorded by eye-movement tracking device. The subjects were required to monitor the state of information targets presented on the primary flight display simulation interface according to the current experiment condition and respond to unusual information by the corresponding operation of the steering wheel. The experiment results reveal good agreement and significant correlation with the theoretical model and hence validate the effectiveness of model.
Progressive failure analysis and crashworthiness experiment for composite structural discreteness
Luo Haibo, Yan Ying, Meng Xiangji, Liang Zudian, Hou Kang, Gong Shaobo
2014, 40(12): 1719-1724. doi: 10.13700/j.bh.1001-5965.2014.0008
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The experimental crashworthiness research on energy-absorbing discrete structures of composite was carried out. The corresponding energy absorption load-displacement curves, the average load, the peak load and the total energy-absorbing parameters were all obtained. Considering the anisotropic constitutive relation of composites, the secondary development of the finite element software was applied. Considering the Hashin failure criterion with the stiffness degradation theory included, the progressive failure numerical analysis was discussed for the structural discreteness. Based on the extended failure criterion, a gradually weakness of layup triggers links style was set up respectively, also the average load of energy-absorbing evaluation parameter was obtained by numerical simulation, which is 361.10 kN. Compared with the experimental results, the relative error is less than 7%, and the numerical simulation results agree well with those of the experiments, which indicate the feasibility and effectiveness of this method to estimate the crashworthiness of composite structural discreteness.
Influence analysis on grid scale limiter of XY-SAS model
Zheng Weilin, Yan Chao
2014, 40(12): 1725-1729. doi: 10.13700/j.bh.1001-5965.2013.0742
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The Xu & Yan scale adaptive simulation (XY-SAS) model is based on the introduction of the von Karman length scale into the destruction term of spalart-allmaras (SA) turbulence model, which results in a large eddy simulation (LES)-like behavior in unsteady regions of the flowfield without explicit grid dependence. Because the SAS models could not provide sufficient damping of the smallest scales, the grid spacing was introduced as the high wave number damping limitation. Three different XY-SAS models were constructed by using various grid limiters and were tested by the numerical example of circular cylinder at Re=3 900. The numerical results were compared with detached eddy simulation (DES) and experimental data. It is concluded that, the grid limiter has a strong influence on the performance of the model and the minimum grid spacing is a good limitation, under which the XY-SAS model performs as well as DES method.
Experimental investigation of biomimetic robotic fish actuated by IPMC
Shen Qi, Han Chenhao, Wang Tianmiao, Liang Jianhong
2014, 40(12): 1730-1735. doi: 10.13700/j.bh.1001-5965.2013.0748
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The thrust efficiency of a biomimetic robotic fish was experimentally measured, which was propelled by an ionic polymer-metal composite (IPMC) actuator. In order to test the thrust performance of the robotic fish, a novel experimental apparatus was developed for hydrodynamic experiments. Under a servo towing system, the IPMC fish swam at a self-propelled speed where external force is averagely zero. A maximum thrust efficiency of 2.3×10-3 at 1 Hz was recorded experimentally, the maximum thrust force was 0.025 3 N, recorded at 1.2 Hz, while the maximum speed was 0.021 m/s, recorded at 1.5 Hz, and a peak power of 0.36 W was recorded at 2.6 Hz. Additionally, the optimal actuation frequency for the thrust efficiency was also recorded at the maximum self-propelled speed. The present method of examining the thrust efficiency may also be applied to the studies of other types of smart material actuated underwater robots.
Nonlinear robust control of valve controlled electro-hydraulic position servo system
Wang Chengwen, Shang Yaoxing, Jiao Zongxia, Han Songshan
2014, 40(12): 1736-1740. doi: 10.13700/j.bh.1001-5965.2013.0752
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To deal with the problem of flow nonlinearity and parametric uncertainties of valve controlled hydraulic position servo system, a nonlinear robust controller was developed based on the Back-Stepping design method. The mathematic model of the valve controlled system was developed, and the nonlinear robust algorithm was derived based on the developed model. The position tracking problem was converted into the load flow planning problem, and the controller was achieved just through one step. The developed controller took the flow nonlinearity and system parametric uncertainties into consideration. The stability of the developed algorithm was proved theoretically. Experimental results show the tracking performance based on the developed controller could be improved compared with that of traditional proportional-integral-derivative (PID) controller.
Effects of different ambient temperatures on performance of electric vehicles' heat pump air conditioning
Peng Fazhan, Wei Mingshan, Huang Haisheng, Zhang Hong
2014, 40(12): 1741-1746. doi: 10.13700/j.bh.1001-5965.2013.0754
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A heat pump air conditioning experimental system for electric vehicles based on the vapor-compression cycle was designed because much energy was consumed for the electric vehicle air conditioning under the heating mode when the ambient temperature was low. The refrigerant temperature and pressure in the high-pressure pipeline, the rate of temperature rising in the cab and the coefficient of performance (COP) for the air conditioning system were studied in the heating mode under different ambient temperatures and different compressor speeds. The test results indicate that, when the ambient temperature and the compressor speeds are higher, the temperature and pressure of the refrigerant at the compressor outlet and the heat exchanger outlet are higher, and the average temperature increases faster and the time reached to the comfort temperature is shorter in the cab. When the ambient temperature is higher in case that the compressor kept the same speed,the COP is greater.
Reliability-redundancy optimization and allocation of voting system under cost constraint
Liu Zhijun, Gao Yakui, Zhang Weiguo
2014, 40(12): 1747-1753. doi: 10.13700/j.bh.1001-5965.2013.0765
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Voting-redundancy structure was adopted in a system to maximize the system reliability under the cost constraint. With the combination of the augmented Lagrangian multiplier method and the fish swarm algorithm, a hybrid method was employed to optimize and allocate the system reliability and redundancies. In the meanwhile, the relationship between the reliability and the cost was not only analyzed, but also the impact of the voter failure rate on the system reliability was discussed. Finally, simulation results based on the longitudinal pitch motion flight control system of a certain type aircraft verify that the quaternion configuration is more appropriate to maintain an optimal system reliability taking into account the cost limit. In addition, in the case of a single voter, the voter reliability should be selected as high as possible. Most of the actual project systems select more voters redundancies structure to avoid the impact of single voter failure on the system reliability.
Analysis of the effect of mass center position on tailslap of supercavitating projectile
Zhao Chenggong, Wang Cong, Wei Yingjie, Ma Qingpeng
2014, 40(12): 1754-1760. doi: 10.13700/j.bh.1001-5965.2014.0014
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The numerical simulation of the cavity morphology in supercavitating projectile tailslap was studied and the rigid body motion parameters and tail-slapping forces variations were comparatively analyzed under different mass centre positions of the supercavitating projectile, based on the theory of homogeneous equilibrium flows, by solving the Reynolds-averaged Navier-Stokes equations (RANS) of mixture fluid, shear stress transport (SST) turbulence transport equations and the mass transport equations between each phase, combined with rigid body motion equations and mesh deformation method. The result shows that the tail-slapping of the supercavitating projectile destroys the symmetry of cavity morphology, the cavity wall of the impact position develops along the direction of the projectile motion; the rotation angle, angular velocity, angular acceleration and tailslap force change periodically, and with the centroid position away from the head of the projectile, the larger the moment of inertia, the greater the period.
Comparison of tissue vibration signal extraction algorithms in shearwave dispersion ultrasound vibrometry
Cai Xiran, Fan Fan, Li Xiaofei, Niu Haijun
2014, 40(12): 1761-1766. doi: 10.13700/j.bh.1001-5965.2013.0741
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Vibration extraction is an important step in shearwave dispersion ultrasound vibrometry (SDUV). There are two primary algorithms for vibration extraction in SDUV, the quadrature demodulation method (QDM) and the cross-spectrum method (CSM). However, the extraction qualities of QDM and CSM are under appropriate comparison. This study aimed at comparing the performance of QDM and CSM for tissue vibration extraction based on a parameterized model under various signal-to-noise ratio of ultrasound echoes (SNRU). Results show that when SNRU≥35 dB, the standard deviations of the estimated vibration phase using the vibration extracted by the two methods are close, which has no significant influence on the calculation result of the shear wave speed. The computation efficiency of CSM for vibration extraction is lower than that of QDM. As a conclusion, when SNRU<35 dB, the tissue vibration should be extracted by CSM to suppress the error of vibration phase estimation. However, when SNRU≥35 dB, the tissue vibration should be extracted by QDM to reduce the signal processing time. The findings may provide some strategy in SDUV, which can optimize the examination protocol and make it more efficient.
A method of stellar-inertial attitude determination under high dynamic condition
Han Li, Zhang Lijun, Cai Hong, Zhang Shifeng
2014, 40(12): 1767-1772. doi: 10.13700/j.bh.1001-5965.2013.0756
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Under high dynamic condition, the accuracy of stellar-inertial attitude determination degraded or even failed to obtain the attitude information because of star image smearing. Based on multiplicative extended Kalman filter (MEKF), a deep integration attitude determination method using gyro and star sensor was proposed. The attitude estimation errors and gyro drifts were compensated by using the star sensor information. The relationship between the gyro output and the pixel motion of the image was established, then the smearing parameters could be estimated by using the gyro output. The star image was restored by using Wiener filter with estimated smearing parameters to improve the signal-to-noise ratio and observation accuracy. Simulation results show that the estimation accuracy of star centroid and the recognition rate of star image can be improved remarkably, the initial attitude estimation errors can be modified faster. The method eliminates recognition mistakes and ensures high accuracy of attitude determination under high dynamic condition.
Application of fuzzy variational principle in solution of natural frequency of structures
Zhang Xudong, Qiu Zhiping, Li Qi
2014, 40(12): 1773-1779. doi: 10.13700/j.bh.1001-5965.2013.0749
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When dealing with the natural frequency of structures with fuzzy parameters, the previous methods are limited to the case that the fuzzy parameters are transformed into the interval parameters before the calculation, and then the fuzzy results are constructed by the interval results. The calculation cost of the previous methods is relatively expensive, so the fuzzy Ritz method and the fuzzy finite element method which are based on the fuzzy variational principle were adopted. By introducing the fuzzy parameters into Rayleigh quotient variation, the fuzzy variational principle was developed. The fuzzy Ritz method and the fuzzy finite element method were proposed as the application of the fuzzy variational principle. These two methods can obtain the fuzzy result directly. Compared with the traditional interval analysis methods, the proposed methods can increase computational efficiency. The numerical example demonstrates that both methods can achieve high computational accuracy and reduce computational cost significantly.
Multispectral imaging simulation of sea-sky background scene
He Xiaoyu, Xu Xiaojian
2014, 40(12): 1780-1785. doi: 10.13700/j.bh.1001-5965.2014.0009
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When an infrared sensor observes sea surfaces at a high zenith angle of the sensor, both sea and sky backgrounds are in the field of view (FOV). By calculating the radiance received by each pixel of the sensor, multispectral optical images of sea-sky background can be obtained. To calculate the reflected radiance of sea surfaces varying with viewing direction under given sea conditions, traditional sea surface radiative characteristic model was modified based on geometrical optics theory. Since the length of transmission path varies with vertical FOV, the effects of atmosphere on radiative transfer are obvious. The radiance of sky light and horizontal path was calculated using a modified atmospheric radiative transfer model. The modified model has higher spectral resolution and is suitable for multispectral imaging simulation. With the improved models, several sea-sky background images were simulated at different time and viewing angles covering the visible up to long wavelength infrared spectral bands, separately. Simulation results are coincident with physical principles. The comparison between simulated and measured images validates the reliability of the new model.
Experimental investigation and numerical simulation of composite laminate adhesively bonded single-lap joints
Liang Zudian, Yan Ying, Zhang Taotao, Li Jianfeng, Meng Xiangji, Liao Baohua
2014, 40(12): 1786-1792. doi: 10.13700/j.bh.1001-5965.2014.0010
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Both experimental tests and finite element method (FEM) simulation were implemented to investigate T300/QY8911 composite laminate single-lap joints with various single-lap length and adherend thickness. 3D finite element models of the joints under various experimental parameters were established. The damage initiation and progressive damage evolution of laminates were predicted based on Hashin criterion and continuum damage mechanics (CDM). The delamination of laminates and the failure of adhesive were simulated by cohesive zone model (CZM). The change of failure modes, damage contours and ultimate-loads of adhesively bonded single-lap joints were investigated systematically under various parameters. The FEM simulation accords well with experimental results which proves the efficiency of FEM simulation. Damage contours and stress distribution of the joints show that the failure modes and ultimate-loads of single-lap joints are both related to the single-lap length and adherend thickness. Simulation of the stress distribution of joints at different loading points reflects damage initiation and evolution of adhesively bonded single-lap joints under extension loads.

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