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2011 Vol. 37, No. 8

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Turbulence modeling validation in hypersonic flows
Geng Yunfei, Yan Chao, Xu Jinglei, Kang Honglin
2011, 37(8): 907-911.
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To provide accurate numerical solutions for selected supersonic/hypersonic flow fields and to compare and evaluate the performance of selected turbulence models with experimental results,four popular turbulence models were tested and validated against experimental data of two turbulent flows. The investigated flows are 2D supersonic expansion-compression corner and hypersonic double ellipsoid. The tested turbulent models were: zero-equation model of Baldwin-Lomax(BL), one-equation model of Spalart-Allmaras(SA), two-equation k-ω/k-ε shear-stress transport(SST) model of Menter and two-equation k-ω model of Wilcox. It shows that the formal turbulent models are competent for the present supersonic flows. However, the simulation of the hypersonic flow, especially for flows at high angle of attack, compressibility modification is needed.
Damage mechanics method to predict the fatigue life of 3-D structural members under spectrum load
Meng Xianhong, Bai Zhaoyu, Zhang Xing
2011, 37(8): 912-917,932.
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A conservative integral of three dimensional structures in damage mechanics was established. The expression of the stress and the strain considering the effect of damage coupling was deduced by means of the path independent property of this integral and the condition of small scale damage. Based on the damage evolution equations expressed by the damage driving force, a closed form solution to determine the fatigue crack formation life under the spectrum load was obtained. According to the above analysis, the damage evolution equation with equivalent stress of non variable separated type was established, and a closed form solution of integral type was obtained to determine the fatigue crack formation life under the short period load. The fatigue life of the landing gear of certain airplane as the representative of 3-D structural member is predicted.
Control response analysis of small coaxial helicopter in hovering state
Xu Guanfeng, Chen Ming
2011, 37(8): 918-922.
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Based on the engineering reality, a calculation model of the rotor unsteady aerodynamics of the small coaxial helicopter in hovering state was set up. An airfoil unsteady aerodynamic model was established by introducing a set of Leishman-Beddoes semi-empirical indicial response formula. The induced velocity of the aerodynamic interaction between upper and lower rotors of a coaxial helicopter was set up by bringing in an interferential factor in the dynamic inflow model, the Runge-Kutta method was used to obtain the numerical solution of the rigid blade flapping angle. According to the calculation and analysis, the thrust and torque response to a rapid collective pitch increase in hovering state was gotten, and the course response differences between the semi-differential and full-differential direction control modes was compared.The results would be a necessary preparation for the research of coxial helicopter-s maneuvering flight.
Experiment and simulation of impinging coaxial gas-gas injector
Gao Yushan, Chen Ze, Li Mao, Cai Guobiao
2011, 37(8): 923-926.
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In order to investigate the effect of design parameters of gas-gas injector on mixing and combustion characteristics, experiment and numerical simulation were conducted on the injectors which had an angle that gaseous hydrogen impinge gaseous oxygen. Hot fire tests were carried out to investigate the effect of impinging angle on the combustion efficiency and the chamber wall temperature. Numerical simulation was performed to analysis the effect of the impinging angle on the temperature of the injector faceplate and the oxygen post tip. The results show that the combustion efficiency, the thermal load of the chamber wall and the oxygen post tip decrease as the impinging angle increases; the impinging angle of the gaseous hydrogen towards gaseous oxygen makes the thermal load of the injector faceplate increases.
Flutter analysis for rudder considering actuator’s dynamics
Zhang Xintan, Wu Zhigang, Yang Chao
2011, 37(8): 927-932.
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Missile rudder-s flutter characteristics are influenced by the actuator-s impedance. Two new methods which can analyze the rudder-s flutter stabilities were used respectively in time domain and frequency domain. Stability judgement of the state matrix was required in the time domain method. Actuator-s impedance characteristics had to be included by the flutter equation which can only be solved by the improved k method when the frequency domain method was used. The two methods- validity was checked by numerical calculation of a rudder model with an actuator. Traditional way of predicting flutter boundary was also used to analyze the rudder, and the flutter velocity/frequency were different from the new methods- results. It indicates that considering actuator-s dynamic characteristics while doing a rudder-s flutter analysis is very important.
Modeling and tradeoff of aircraft survivability based on combat capability
Wang Huaiwei, Li Shulin, Tong Zhongxiang
2011, 37(8): 933-936,947.
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There is a deficiency in existent model when calculating aircraft survivability in active self-defense,a new calculating model was proposed. Relationship among aircraft-threat-survivability-combat capability was analyzed by combination of attack and defense. The calculating model involving aircraft combat capability was established and validated by an example. Weight was introduced to express different demand of survivability and combat capability in a specific task. Taking weapon delivery range as control variable, multi-attribute decision making on survivability and combat capability was implemented by using the technique for order preference by similarity to ideal solution(TOPSIS). It can be concluded that under given demand of survivability and combat capability, the best range to deliver weapon exists and it varies with the demand. This work can be used to instruct the planning of real battle.
Analysis of effects of BWB airliner design parameters on its economic profitability
Zhao Zhigao, Zhang Shuguang
2011, 37(8): 937-942.
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In order to analyze economic profitability due to high cruise L/D and higher engine performance of blended wing body (BWB) airliner, the methods of estimating major parameters and calculating flight performance were imposed. Using fuel flow per capita (Fuel/km/seat) as the weighing standard, quantitative analysis was operated on the effects of cruise L/D and specific fuel consumption on 250-seat and 450-seat airliner; then contrasts BWB airliner family with existing equivalent conventional airliner and the material data of economic profitability was obtained. Moreover, analysis was operated on effects of seats and range. In the end conclusion was made on the trend and characteristic of BWB airliner family development and then considering the balance between benefits and realizing difficulty, the reasonable design parameters are given.
Effects of driving load and pipe diameter on flow characteristic of two-phase boiling water
Ma Qicheng, Song Baoyin, Shan Shaorong
2011, 37(8): 943-947.
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The centrifugal force resulted from a rotational platform was used to simulate the flying load and the experiment of two-phase boiling water flowing in different diameter pipes under driving load was conducted. By changing the parameters, such as driving load, pipe diameter, flow rate, and so on, some flow characteristics of the boiling water were obtained. The image of flow patterns under dynamic load was obtained with a video camera. The results reveal that the dynamic load whose direction is the same as the flow direction and pipe diameter dramatically influence the flow characteristic of the boiling water. Some new flow patterns were observed under dynamic load. In addition, the dynamic load weakens the flow stability of the boiling water. The greater the dynamic load, the lower the pressure drop. And for a bigger diameter pipe, the pressure drop will decrease more obviously. The experimental data can be added to the database in the flow characteristic of gas-liquid two-phase pipe flow under dynamic load, and can be a reference in developing the vapor-cycle cooling system for flying vehicles.
Measure of reaction wheels disturbance considering coupling effect
Zhang Pengfei, Cheng Wei, Zhao Yu
2011, 37(8): 948-952.
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The micro-disturbance of reaction wheel assembly (RWA) is a key factor which will affect the accuracy of spacecraft attitude control. To obtain the disturbance characteristics,the RWA disturbance was meaured,corresponding control methods and isolation systems were adopted to restrain them. The disturbance coupled with the nature frequency of test bed since the bandwidth of RWA disturbance was wide. Accelerance measurement method was used to express the effect which the test bed had on measure results. And the mechanical model of RWA was built, in order to obtain the pure disturbance of RWA. Two test beds with different rigidity were designed to measure the RWA disturbance. Amplification coefficient was used to modify the measure results. To acquire the disturbance without affect of test bed rigidity, and results from two equipments were compared. The results show that accelerance measurement combined with mechanical modeling method captures the affection of test bed rigidity on measured disturbance effectively.
Mechanical ergonomics analysis of capstan partial pressure suit under pressure
Zhang Chunguang, Ding Li, Qin Zhifeng, Xiao Huajun
2011, 37(8): 953-957.
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To discuss the human operating ergonomics at different pressure level for the capstan partial pressure suit (PPS),range of motion (ROM), operational flexibility, grip strength test and subjective survey were performed by ten male subjects while wearing PPS under 6 pressures. The control group was under 0kPa. The results show that: ①The PPS pressures have significant impacts on operating ergonomics (P<0.05). Shoulder joint and hip joint are more sensitive to the pressure and decrease 62.2% and 42.3% respectively under 1.96 kPa. Under 10.49 kPa, two indexes of ROM decrease the most: shoulder extension by 83.1%, and neck rotation by 63.3%; ②Upper lamb is affected more severely by pressure than the lower lamb; ③The pressure has no significant influence in grip strength test (P>0.05); ④The consistence of subjective test results and the objective data reflects the human body compensatory response to different pressures. The results provide basic data for ergonomic evaluation and can be practically applied for improving the performance of PPS.
Variable selection in discriminant analysis based on Gram-Schmidt process
Wang Huiwen, Chen Meiling, Gilbert Saporta
2011, 37(8): 958-961.
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A new linear discriminant analysis modeling method based on Gram-Schmidt process was introduced, which firstly selected the most effective variables for classification in the independent variables set. In the meantime, the insignificant variables and the redundant information were identified and removed from the independent variables set. The selected variables were transformed into a set of orthogonal vectors by Gram-Schmidt process. Not only can the proposed method accomplish variable selection in linear discrimination, but also overcome the multi-collinearity problem effectively. Since F-statistic works as a criterion to verify the discrimination effect of each selected variable, it helps analysts to understand the analysis result. In order to test the reasonableness and effectiveness of the method, a simulation experiment was carried out. The result indicates that the proposed method can lead to a reasonable and precise conclusion.
Weakly-hard real-time scheduling algorithm for wireless networks
Jiang Yule, Wang Hailiang, Xiong Huagang
2011, 37(8): 962-967,996.
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A (m, k)-firm scheduling algorithm combined with wireless channel state consideration was proposed. The algorithm classified the messages into mandatory ones and optional ones, and scheduled the mandatory messages in higher priority. The message type was jointly decided by static offline assignment and dynamical online adjustment. The static assignment used (m, k)-pattern to assign the message types, and the dynamic adjustment adjusted message types by trying to reduce the number of mandatory messages in the bad channel state without breaking the (m, k)-firm constraints. The theoretical analysis prove that ①the dynamic adjustment will not break the (m, k)-firm constraints if assuming all the mandatory messages can be transmitted successfully before deadline, and ②the dynamic adjustment will not change the mandatory messages- schedulability when using evenly distributed (m, k)-Pattern. The simulation results show that compared with the algorithm that assigns message types in static way this algorithm can improve the schedulability and save the wireless networks- bandwidth and energy.
Steady state circular performance simulation of automobile based on orthogonal test
Jiang Libiao, Hou Wenchao, Gu Fangde
2011, 37(8): 968-972.
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The perfect combination of virtual simulation technology and orthogonal experimental design methods provides a new idea for the automotive product development. The research of steady state circular performance of automobile can follow the following steps. A virtual prototype model of a car was established in multi-body dynamics simulation software automatic dynamic analysis of mechanical systems(ADAMS); The testing program was reasonably designed using orthogonal experimental design methods; Some simulation tests were carried out in ADAMS following the designed testing program; The optimal testing program and the influence degree of every factor were elicited after the test data being calculated and analyzed. The results show that the four factors which have considerable influence to the steady state circular performance of automobile are the location of mass center in lengthwise, the cornering stiffness of front and rear tires, the height of mass center, the stiffness of front spiral spring, according to the order of influence degree.
Axial radial magnetic bearing in magnetic suspending switched reluctance motor application
Zhao Xusheng, Deng Zhiquan, Wang Bo
2011, 37(8): 973-978.
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To overcome the defects of the present permanent magnet biased axial radial magnetic bearing, a new permanent magnet biased axial radial magnetic bearing (PARMB) was studied, which was used in magnetic suspending switched reluctance motor application. The configuration and fundamental principle of PARMB were analyzed. The equivalent magnetic circuit was established to deduce the mathematical models of PARMB. The parameter design and calculation were presented. The parameters of the proposed prototype were also given. The 3-D magnetic field simulation was performed by using the finite element software. The theory analysis and the simulation show that the presented PARMB has smaller volume compared to the existed structure, here is no coupling between axial and radial directions, the control is easier than before. Therefore, the proposed PARMB is more suitable for the high speed or low loss occasions.
Accuracy analysis and synthesis of 3-RPS parallel machine based on orthogonal design
Li Xinyou, Chen Wuyi, Han Xianguo
2011, 37(8): 979-984.
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To analyze the influence degree of pose parameters on pose errors, and to guarantee the accuracy requirements of 3-RPS parallel mechanism in the whole workspace, the orthogonal design method was adopted for accuracy analysis and accuracy synthesis. According to the orthogonal design method, three pose parameters of 3-RPS parallel mechanism were considered as three factors for pose errors, and the pose error values from range analysis were introduced as error sensitive indexes. The influence degree of pose parameters on pose errors were obtained through range analysis. The factors were divided into reasonable levels based on the ratio of error sensitive indexes, and then more reasonable poses from orthogonal table were provided for accuracy synthesis. Accuracy synthesis was carried out according to the orthogonal table and tolerance values of 21 geometry original errors were derived according to accuracy requirements. The result shows that: By applying the orthogonal design method in accuracy analysis and synthesis, the influence degree of pose parameters on pose errors was analyzed completely, the accuracy synthesis results ensure the accuracy requirements in the whole workspace and a reference was provided for the development of prototype.
Calculation and error analysis of the electric field for a quasi-reciprocal optical voltage sensor
Feng Xiujuan, Zhang Chunxi, Yu Jia, Li Chuansheng
2011, 37(8): 985-989.
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The optical sensing element in transverse modulation configuration utilizing the Bi4Ge3O12 (BGO) crystal was designed for a novel optical voltage sensor with quasi-reciprocal reflective optical circuit. The numerical calculation of electric field was performed using the finite element analysis based software ANSYS and the distributions of both electric field and electric potential were obtained. The influences of the non-uniformity and disturbances of electric field on the accuracy were also analyzed. The simulated results show that the maximal voltage that can be measured is not less than 15 kV at the standard temperature and pressure for the designed sensing element. The integral results of the electric field along different paths are different due to its non-uniformity, which affects the stability and accuracy of the voltage sensor. It can not be ignored for the voltage sensor with the requirement of accuracy 2‰ that the maximal relative measurement error is up to 1.2‰ caused by the disturbances of electric field with the measured voltage from 0 to 5 kV.
Key technology on PROFIBUS-DP master gateway
Xia Jiqiang, Liang Chaozhong, Geng Chunming, Chen Xuejun
2011, 37(8): 990-996.
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To solve the problem that distribute control system is difficult to integrate standard PROFIBUS-DP slaves, gateway solution was proposed. After comparing several existing gateway solutions, soft core implementation was adopted. Hardware platform which was compatible with two solutions and supported hot plug operation was designed. Modular thought was applied to do software architecture designation. State-machine method was used to implement "PROFIBUS-DP communication" sub function. Solution reliability on both hardware and software was traversed from the view point of chip selection, fault-precaution, fault-rectify and failure-resume. Proper schedule strategy to enhance system-s real-time performance was expatiated according to hardware-s characteristics. Slave-s configuration method which is a difficult point when it comes to self-designed host was designed to support add and delete slave as well as edit slave configuration dynamically when system is running. Theoretical analysis and experimental test were done to identify gateway-s capability parameters. The gateway can support up to 3 Mbit/s communication baud rate. Experimental results show that system performance is excellent and stabilized.
Voice coil motor for direct drive valve optimization design by means of particle swarm optimization
Wu Shuai, Wang Dayu, Xing Qiujun, Jiao Zongxia
2011, 37(8): 997-1000.
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Voice coil motor (VCM) direct drive valve (DDV) is a type servo valve which utilize the VCM drive spool directly and its dynamic characteristic is depends on the performance of VCM. Unfortunately, some of design parameters of VCM are contradictory when ambition the best performance, it always need to trial-and-error many times by designer. Based on the introduction of principle and structure of VCM, the effect of each design parameters for the performance was analyzed, and the parameters need to be optimized synthesized was pointed out. The optimization objective function was defined under the design constraint, and the improved particle swarm optimization (PSO) methods which use inertia weight and constriction coefficient were applied for search the optimum parameters in multidimensional parameters space. The best parameters were obtained under design constraint. It also improve that PSO is an efficient way to solution these questions.
Adaptive sampling frequency offset estimation algorithm for OFDM system
Sun Yuming, Zhang Yanzhong, Shao Dingrong, Li Shujian
2011, 37(8): 1001-1005.
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The estimation formula of sampling frequency offset estimation algorithm based on data decision was corrected. An orthogonal frequency division multiplexing (OFDM) system adaptive sampling frequency offset estimation algorithm was presented. The frequency offset change using discrete pilots to find the interval of the data symbol was estimated, and the sampling frequency offset estimation using the channel estimation results and the received data at the same time was implemented to improve the estimation precision. The simulation results show that, the estimation precision of the new algorithm is higher than the method using pilots or data decision respectively about 3 dB in additive white Gaussian noise channel, and about 5 dB in multipath fading channel. The experiment results show the constellation could be converged better. Therefore, the receiver performance could be improved.
Whole life-cycle costing analysis of pneumatic actuators
Zhang Yeming, Cai Maolin
2011, 37(8): 1006-1010.
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Combined with the concept of air consumption and specific energy, and analyzed the energy consumption of pneumatic actuator, a power consumption calculation method of pneumatic actuator was proposed. In order to solve purchasing cost allocation problem of public pneumatic devices, a novel air equipment costs average method (AECAM) was put forward. A new analysis model of entire life-cycle costing based on the users (LCCBOU) of pneumatic actuator was established with the concept and thinking of LCC. A case study validates the model. This model was not only suitable for the entire life cycle cost analysis of pneumatic actuator, is also suitable for cost analysis of other pneumatic equipments. The AECAM achieves a rational division of pneumatic systems costs. LCCBOU model of pneumatic actuator has passed through the case validation, and a new fact is found that the model results can be more accurate, more realistic by real-time monitor of air compressors and pneumatic system leakage measurement.
Die-face compensation algorithm in stretch forming of aircraft skin over reconfigurable compliant tooling
Wang Lili, Li Dongsheng, Li Xiaoqiang, Luo Hongyu
2011, 37(8): 1011-1016,1020.
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Two finite element models of a single curvature part, discrete and equivalent models of stretch forming over reconfigurable compliant tooling, were set up. The calculation times, rubber deformations and part shapes in two models were compared. The result shows the equivalent model is reliable and more efficient. To eliminate the influence of springback and the interpolator deformation on the part shape fidelity, a die-face compensation algorithm was proposed based on displacement adjustment method and equivalent model. In the algorithm springback compensation and deformation compensation of interpolator were performed in sequence. This algorithm was applied to compensate the die-faces of a single curvature part and a double curvature part. Finally, the two parts were stretch-formed over compensated die-faces and measured by non-contact three-dimensional measurement techniques. The results show that the shape errors are both within tolerance (±0.5 mm) and meet the requirements. It is proved that the algorithm is effective.
Life prediction of thrust bearings based on accelerated wear test
Zhou Yuhui, Kang Rui, Su Li, Wu Jianjun
2011, 37(8): 1016-1020.
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The life prediction of thrust bearings was gotten by using accelerated wear test based on degradation model for the life verification of the thrust bearings with good wear-resisting property, and its life prediction model for the accelerated wear test was proposed. Based on the analysis of the failure mechanism, the accelerated wear test was conducted for 7 200 h considering the load as an accelerated stress, the data of the wear volume indicating the degradation of the wear-resisting property were gotten and 0.94 of the reliability with 90% of the confidence level was predicted for the thrust bearings running for 10 a at service conditions. It is shown that the test time and cost can be saved by using the data of the accelerated wear test to predict the life of the thrust bearings with high-reliability, long-lifetime and very small wear rate.
Cycleslips detecting approach for single frequency GPS Users
Gao Shuliang, Huang Zhigang, Li Rui
2011, 37(8): 1021-1025.
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Aiming at the detection of the cycle slips in the carrier phase measurements for the single-frequency global pesition system(GPS) users, a novel algorithm was proposed based on the conventional method with the combination of the pseudo range and the carrier phase. The pseudo range and the carrier phase were differentiated between the adjacent epochs and a related detection sequence could be constructed. The real-time estimation of the variance for the detection sequence was accomplished with the elevation exponential model as the conventional method was susceptible to the measurement noise. Finally,a detection variable was formed and the existence of the cycle slips were judged by the comparison between the detection variable and the threshold which is deduced from the hypothetic check theory.The algorithm was verified by the real GPS measurements and the results indicate that the small cycle slips can be detected with the algorithm timely.Moreover,the algorithm is available for the single-frequency GPS users.
Coordinates conversion of software radar based on improved CORDIC algorithm
Xia Dong, Cha Hao, Zhou Mo, Huang Ying
2011, 37(8): 1026-1029.
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Radar data processing and terminal display realized by software on general-purpose computer becomes a trend now. And fast conversion from polar coordinates to orthogonal coordinates is required in real-time radar-s display. The value of azimuth angle increases evenly in radar display processing, and the next azimuth angle value can be got by the same tiny increment added to the current value. An appropriate increment was selected to satisfy the coordinate rotation digital computer(CORDIC) algorithm-s demand as well as meet the need of radar display. And based on above, the CORDIC algorithm was improved. The improved CORDIC algorithm can calculate the trigonometric function only by one rotation, which accelerates the speed of conversion from polar coordinates to orthogonal coordinates. Though analysis, the improved algorithm is 15 times faster than the original algorithm.
High-accuracy frequency estimation algorithm based on autocorrelation and phase difference method
Yang Dezhao, Song Ningfang, Lin Zhili, Ou Pan
2011, 37(8): 1030-1033,1043.
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In order to improve the frequency estimation accuracy of sinusoidal signal in white Gaussian noise, the correlation length m of the algorithm based on the autocorrelation operation was derived, and the equation representing the relationship of m and signal-to-noise ratio (SNR) was acquired. Given the data length N, the optimum value of m was N/3 when the SNR was large and it was N/2 when the SNR was small. The performance of segmented-FFT phase difference method and autocorrelation method were analyzed, and a new frequency estimation algorithm was proposed. The Monte Carlo simulation results verify that the new algorithm combines the advantages of the two methods previously mentioned, and avoid the disadvantages of them. It can fetch the highly accurate frequency of a signal in a wide range of SNR, and the computational cost is small.
Realistic rendering of virtual earth in real-time application
Wang Cheng, Dai Shuling
2011, 37(8): 1034-1038.
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A new approach was proposed to enhance realism of virtual earth in VR-based real-time applications. A virtual earth which had 21 600×10 800 pixels surface texture, bumping surface and shine of atmosphere was constructed.The whole virtual earth was cut into 128 parts and then the position of vertices, normal vectors, texture coordinate were calculated by geometry. Using the techniques of the mixture of the textures of earth, normal and clouds, it achieved relatively vivid surface of the earth. By moving and scaling the board which had atmosphere texture, it showed the shine of atmosphere. To achieve good real-time, it eliminated the unvisible parts by judging the parts- visibility in real-time, and chose different resolutions of texture. Experiments show that this approach is able to run 45 frames per second with 1.02GB texture pixels.
Determination of corrective maintenance task item for materiel
Mao Yilan, Kang Rui, Ma Lin, Xu Zhehan
2011, 37(8): 1039-1043.
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In order to achieve the integrality of the supportability analysis during the development phase of materiel, the determination method of corrective maintenance task items was presented based on the characteristics of failure mode, effects and criticality analysis(FMECA), the calculation of semantic similarity and the research of similarity for the units and systems. This method accounts for the bias of similarity calculation of units which is due to the unsurely level of unit-s failure mode, and according to the similarity of units to complete the quantitative similarity calculation of system to assist the determination of corrective maintenance task items which depends on the similarity of different materiel. In addition, because of using the computer-aid, this method not only improves the effect and efficiency for the calculation process, but also somewhat avoids the differences between different supportability analyzers because of their own experiences and diversity. This method regulates the process of determination of corrective maintenance task items. The final example proves the method is effective.
High voltage pulse electron beam control strategy and influence on weld bead shape
Xu Haiying, Yu Wei, Zuo Congjin
2011, 37(8): 1044-1048.
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A 150 kV/30 kW high voltage pulse electron beam welding power source was developed. The bias pulse power source topology and control technique about base beam current, peak beam current, pulse beam duty, pulse beam frequency were introduced. Not only the biggest peak beam current up to 200 mA has been exported by this power source at 0-1 kHz, but also weld technology parameters are expediently adjusted. The 1Cr18Ni9Ti stainless steel work pieces had been welded by electron beam welding and pulse electron beam welding. These weld bead shapes had been studied and analyzed. In contrast with electron beam welding, weld penetration will be increased by pulse electron beam welding introduced. At the immovable pulse beam duty, the weld faults will be reduced with the pulse beam frequency being increased. Through these weld tests, besides beam frequency and duty are substantiated key technique parameters for weld shapes, it also shows that pulse modulated bias power source technique is an applicable technology to achieve high voltage pulse electron beam.

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