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2014 Vol. 40, No. 5

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Energy-based hybrid reentry guidance for hypersonic vehicles
Wang Qing, Mo Huadong, Wu Zhendong, Dong Chaoyang
2014, 40(5): 579-584. doi: 10.13700/j.bh.1001-5965.2013.0383
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An energy-based hybrid reentry methodology was developed for hypersonic vehicles. The three-degree-of-freedom reentry kinematic equations was conducted based on energy, and typical inequality constraints was converted to the constraints of bank-angle by using quasi-equilibrium glide condition (QEGC). Longitude guidance used a constant bank angle in initial descent, and segmented the standard trajectory in quasi-equilibrium glide phase since the range-to-go was monotonically decreased with energy, then used predictor-corrector online in every segment to reduce the calculating time. Lateral guidance designed a lateral reversal logic based on the crossrange corridor for crossrange varied almost linearly with energy between two bank reversals. The simulation results show that the proposed algorithm has the obvious decrease of calculating time, high guidance precision and is not sensitive to initial errors and disturbers.
Robot error calibration based on distance measurement with parameter selection
Zhang Tie, Dai Xiaoliang, Du Liang
2014, 40(5): 585-590. doi: 10.13700/j.bh.1001-5965.2013.0372
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To eliminate singularity in robots' kinematics calibration, identifiable parameters in distance square difference model were confirmed. Robot's link structure was expressed by modified Denavit-Hartenberg (DH) model, while the transformation between last joint and tool frame by six parameters. The linear model from link parameter errors to distance's square difference of robot's end-effector was derived. After redundant parameters eliminated via redundant expressions and physical interpretation, complete and nonsingular model was identified by iterative least square algorithm. Experiment was conducted with a 6 rotational robot and Leica laser tracker. Measured target should be away from the last joint's axis in order to guarantee penultimate joint parameters identifiable when end-effector was designed. The result shows that the model avoids coordinate transformation, the error distance's root-mean-square of inspection data reduced 93.1% and completeness and non-singularity improved identification effectiveness.
Influences of aerodynamic layout of single main rotor helicopter on flight performance
Su Yuan, Lü Shaojie, Cao Yihua, Li Guozhi
2014, 40(5): 591-595. doi: 10.13700/j.bh.1001-5965.2013.0386
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To investigate flight performance of the signal main rotor helicopters with different aerodynamic configurations based on helicopter nonlinear flight dynamic model, trim calculation of main rotor required power in case of level flight, steady-climb and descent, and steady coordinated-turn under baseline aerodynamic layout were conducted. The flight performance indicators were calculated. The agreement between the computational results and the referenced data indicates that the model is feasible. The flight performance of UH-60A helicopter was calculated and analyzed with variable aerodynamic configuration parameters. The results show that, in the range of variation, main rotor position parameters have significant influence on both level flight and vertical flight performance, the decrement of rotor longitudinal distance can improve flight performance dramatically, tail rotor canted angel has major impact in hover and low speed, moving backward of the longitudinal position of horizontal tail is helpful to improve the maximum level flight velocity.
FOG ring modules thermal analysis based on thermoelectric analogy
Liu Haixia, Jiang Yaofei, Song Ningfang, Jia Ming
2014, 40(5): 596-601. doi: 10.13700/j.bh.1001-5965.2013.0350
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For the fiber-optic gyroscope (FOG) was easily influenced by the ambient temperature resulting Shupe bias, the thermoelectric analogy method was applied to do the thermal analysis of different structural fiber optic ring (FOR) modules. The principle that the parallel heat capacity and series resistance were the key factor on the FOG thermal performance was proposed by comparing the corresponding circuit model. The parallel heat capacity and series resistance affecting the FOG temperature qualitatively was analyzed and the correctness of the circuit model was verified via finite element thermal simulation. In the same condition with the thermal simulation, the FOR temperature was associated with the FOG output performance after a temperature test cabinet experiment. The results show that increasing the parallel heat capacity and series resistance in FOR modules can reduce the ambient temperature effect on the FOR. Especially, the larger heat capacity can effectively reduce the FOR temperature change rate, thereby reducing the Shupe bias and improving the FOG thermal performance.
Remaining useful life prediction for equipment based on conditional probability of states
Zhang Jijun, Deng Li, Ma Dengwu, Cao Wenjing
2014, 40(5): 602-607. doi: 10.13700/j.bh.1001-5965.2013.0361
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To conquer the question of uncertain factors in the remaining useful life (RUL) prediction of airborne equipment, a RUL model was presented based on the conditional probability distribution of states. Firstly, the conditional probability vector of states was introduced to improve the ability of hidden Markov model (HMM) to deal with uncertainties, and its computation form was deduced. Secondly, a method was presented to approximately determine the degradation transfer time of states, thus the conditional reliability function and RUL model were obtained, in which the conditional probability vector of states was taken as the covariate. Lastly, the aero-engine temperature control amplifier was applied to validate the model. The results show that the prediction precision of this model is high, and this model can reduce the influence of uncertain factors greatly.
Effect of shot-peening on low-cycle fatigue property of 18% Ni ultra-high strength steel
Wang Xin, Jiang Zhihua, Zeng Houxiang, Tang Zhihui
2014, 40(5): 608-612. doi: 10.13700/j.bh.1001-5965.2013.0388
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18% Ni ultra-high strength steel C250 was employed to investigate the effect of single shot peening (SSP) with cast-iron bead and double shot peening (DSP) with cast-iron bead and glass bead on surface topography, micro-structure and low-cycle fatigue (LCF). The results show that the low-cycle fatigue life has risen by nearly 2.5 times due to SSP, however, the low-cycle fatigue life after DSP increases by 3 times. Moreover, the sub-grain refinement after peening is the main factor which extends the LCF life, and the smooth surface caused by DSP promotes the LCF property. Furthermore, by comparison with fatigue fracture of unpeened and SSP sample presenting multi-source crack initiations, the DSP one fractured with only one source due to the smooth surface.
Construction of shock stable scheme based on RoeM scheme
Qu Feng, Yan Chao, Yu Jian, Zhong Chongyan
2014, 40(5): 613-617. doi: 10.13700/j.bh.1001-5965.2013.0341
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Roe's flux difference splitting (FDS), a widely used scheme today, encounters shock inability that needs to be avoided in hypersonic flows. Moreover, it can't preserve the total enthalpy while in steady inviscid flows' simulations. To get over the defects above, schemes called RoeMW1, RoeMW2 that are based on the construction of RoeM scheme were proposed to cure the shock inability and preserve the total enthalpy while in steady inviscid flows' simulations. The results tell that in most simulations the RoeMW1 and RoeMW2 schemes can achieve the goal of curing the shock inability and keeping the conservation of total enthalpy. In addition, both RoeMW1 and RoeMW2 are better than RoeM. However, in some complex situation the RoeMW2 scheme constructed by some improvement of the RoeMW1 is more robust than RoeMW1.
Design of static balance testing system for coordinator gyro rotation axis
Yang Hui, Zhao Yan, Li Min
2014, 40(5): 618-623. doi: 10.13700/j.bh.1001-5965.2013.0367
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A static balance testing system for coordinator gyro rotation axis was desired to do a test about the static unbalance value and distributed position angle. In this system, the measured axis of the coordinator gyro was mounted parallel with the horizontal turntable axis by the direction of the fixture. Measurement and control system drove the turntable turned to 36 lock horns, which was set in advance. Then in every lock angular position, two axes of the coordinator were locked with the servo control signals, and another measured axis was drove to rotate with sine small-angle in the same time. The static unbalance moment was calculated with the multi-cycle integration of the driving current amount. After a round rotation, 36 position values were measured, which were then used to deduce the static unbalance value and the distribution of angular position with least-squares fitting method. Loading test was carried out repeatability. According to the result, the static unbalance measurement precision can reach ±0.25 mN·m and the angular position measurement precision can reach ±2°, which shows that the system has a good performance.
Model of overlapping effect of levitation lunar dust
Chen Kuo, Li Na, Feng Huajun, Xu Zhihai
2014, 40(5): 624-628. doi: 10.13700/j.bh.1001-5965.2013.0369
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During lunar exploration program, the dust on the lunar surface has a severe impact on the energy utilization efficiency of photoelectric devices, such as solar panels. Based on the model of adherence dust, the effect of levitation dust was analyzed from the view of stereo space. The model of levitation dust, which had the same diameter, was proposed. With the average diameter of the lunar dust, the quantitative relationship between the levitation density of lunar dust and the energy utilization efficiency could be calculated by this model. Then taking the size distribution of the lunar dust into consideration, the model of multi-granularity levitation dust was built, with which the quantitative relationship between the levitation density of lunar dust and the energy utilization efficiency could be calculated for dust with known distribution. A simulation experimental model of levitation dust was set up and experiments were made thrice with different size distributions. The experimental results are matched well with the theory model of either single particle size dust or multi-granularity dust, which verifies the correctness and the reliability of the proposed model of the levitation dust.
Reentry trajectory optimization design for lunar return through coevolutionary algorithm
Wang Fengbo, Dong Changhong
2014, 40(5): 629-634. doi: 10.13700/j.bh.1001-5965.2013.0376
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Reentry trajectory optimization with multiple constraints on g-load, dynamic pressure, heat flux on stagnation point of craft and parachute deployment position was studied for low-lift-to-drag lunar return vehicle, and a novel coevolutionary algorithm was presented to solve the parameters optimization problem based on the piece-wise linear bank modulation strategy. Firstly, a piece-wise linear bank modulation versus energy policy was introduced to convert the continuous optimal problem into a finite-dimensional parameter optimization problem. Then, the coevolutionary algorithm consists of escapable particle swarm optimization algorithm and adaptive differential evolution algorithm was employed to solve it. Numerical simulation demonstrates the feasibility of the adopted control parameterization strategy. A performance comparative case was carried out. The coevolutionary algorithm proves to be effective with great accuracy and is well suited for reentry trajectory optimal profile design.
Experiment on thermal storage performance of barium hydroxide octahydrate phase change material
Sheng Qiang, Xing Yuming, Luo Heng
2014, 40(5): 635-638. doi: 10.13700/j.bh.1001-5965.2013.0385
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Thermal cycling tests were performed to determine the phase change temperature shift of pure barium hydroxide octahydrate (Ba(OH)2·8H2O) phase change material (PCM) with respect to 150 accelerated thermal cycles. The results show a slightly phase change temperature shift and a severe supercooling phenomenon with the increasing number of thermal cycles. The compatibility of Ba(OH)2·8H2O with the PCM containing materials like aluminum alloy and copper was also studied by using scanning electron microscope (SEM) after 50 thermal cycles. Ba(OH)2·8H2O was a stable PCM with good compatibility with copper as a containing material. An experimental setup was built to study the heat transfer performances of Ba(OH)2·8H2O with/without copper foams. The contrast experiments conclude that high porosity metal foams not only significantly enhance the heat transfer rate of PCMs, but also effectively reduce the supercooling degree of Ba(OH)2·8H2O.
Full compensation combined control for heater with high heating rate
Li Wanguo, Fu Yongling, Qi Xiaoye
2014, 40(5): 639-643. doi: 10.13700/j.bh.1001-5965.2013.0573
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Contact-type conduction electric heater was developed for testing high-temperature material under both heat and pressure. For this heater, temperature control under high heating rate was studied. The specificity of the mathematical mode of general heaters under high heating rate was analyzed, therefore approximately full compensation feedforward-feedback combined control (FCCC) was presented. Corresponding experiments prove the deduced mathematical model. Moreover, comparative experiments of classical PID control and the FCCC were performed. The results show that the FCCC has better tracking performance for temperature curve, better stability and higher ability to restrain head-region of the heating electric power supply. The FCCC is applicable to general heaters, because the deduced mathematical model is suitable for high heating rate operation of general heaters.
Agile satellite attitude maneuver strategy study based on directed acyclic graph
Tang Zhongxing, Han Chao
2014, 40(5): 644-650. doi: 10.13700/j.bh.1001-5965.2013.0347
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Compared to the traditional Earth observation satellites, the agile satellites have more degrees of freedom for attitude maneuver and complex observation modes. An agile satellite attitude strategy based on time-ordered directed acyclic graph was proposed for the one-orbit strips-jointed and multi-spots observation modes for the agile satellites in its one pass time window. Firstly, the area target and the spot targets were divided into a certain number of strips. And then, the observation time windows of these strips were discretized into a series of time points with their strips information. With these time points, a time-ordered directed acyclic graph was constructed. After that, the attitude maneuver problem for the agile Earth observation satellites was described as the optimal path problem based on the time-ordered directed acyclic graph theory. The simulation examples prove the availability of the attitude maneuver strategy for the agile satellites in one-orbit strips-jointed and multi-spots observation modes based on time-ordered directed acyclic graph. And that the strategy, maximizing observation coverage and minimizing maneuver time cost would be got at the same time, was obtained by this method.
Adaptive tracking algorithm for reentry vehicle based on stochastic model approximation
Zhou Zheng, Liu Jinmang, Guo Xiangke
2014, 40(5): 651-657. doi: 10.13700/j.bh.1001-5965.2013.0359
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For the problem of reentry vehicle (RV) tracking, adaptive piecewise constant Jerk model and tracking algorithm were proposed based on kinetics acceleration model and stochastic model approximation. Recursive model of target acceleration was induced by introducing kinetics Jerk model and assumption of piecewise constant Jerk. A new definition and adaption method of process noise was proposed according to the idea of stochastic model approximation. The real-time RV tracking was achieved by divided difference filter based on the augmented state model. Simulation results show that the proposed algorithm has the similar tracking accuracy on stable state as the tracking algorithm based on the piecewise constant acceleration model, but it has better performance on tracking state mutation than the latter.
Probabilistic sensitivity for failure of multiple site damage in aircraft structures
Du Yongen, Wang Shengnan
2014, 40(5): 658-661. doi: 10.13700/j.bh.1001-5965.2013.0374
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Different structure crack initiation position may affect the performance of the structural safety in structures containing multiple site damage. Considering that, a method to analyze the sensitivity of failure probability with respect to the stress and crack initiation life on each site was proposed to quantify their impact on the structural safety performance. A probabilistic sensitivity analysis model for failure of multiple site damage in aircraft structures was put forward using a kernel function. The Monte-Carlo simulation results in probability analysis were used to obtain the probabilistic sensitivity with a slight increase in the amount of calculation. This method was applied in analysis of a collinear porous plate, and the site with greatest impact on structural safety was identified using the probabilistic sensitivity.
Modeling and dynamic characteristics experiment of novel linear oscillating motor
Liang Huisheng, Wang Tianyi, Jiao Zongxia, Yan Liang, Wang Xutian, He Ping
2014, 40(5): 662-667. doi: 10.13700/j.bh.1001-5965.2013.0659
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According to the proposed new principle of directly-driven hydraulic serve pump, a novel short stroke permanent magnet linear oscillating motor (LOM) was designed. The LOM working principle based on minimum reluctance rule was elaborated, and a special hollow mover design structure employing Halbach PMs array was adopted to improve the motor dynamic response ability and facilitate the installment of resonant springs. The lumped parameter mathematical model and transform function of LOM was established by Matlab/Simulink. Through sinusoidal voltage frequency sweep excitation, the LOM frequency characteristics of current with no load and of efficiency with constant load was acquired. According to the motor model, a dual-loop control structure with current loop and position loop was designed to improve the current frequency response and position tracking performance. Finally, the LOM experiments for unloaded resonance and dual-loop control strategy were carried out. The experimental results are coincided with the simulation results basically and verify the effectiveness of LOM model and control structure.
Automatic modeling technique for tightly correlative structure in aircraft manufacturing tooling
Cao Wei, Zheng Guolei, Qiu Yi
2014, 40(5): 668-674. doi: 10.13700/j.bh.1001-5965.2013.0668
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Tightly correlative structures are widely used in aircraft manufacturing tooling, elements which constitute them have rigorous correlations in the spatial orientation and structural dimensions, but sometimes they do not constitute a complete assembly as independent part of the overall structure attached to the tooling. Tedious manual operations are needed to model these structures by existing techniques. In order to realize automatic modeling for these structures, a technique of virtual assembly parts was proposed, based on associated relation in structure. Firstly, concept of virtual assembly parts was introduced on the basis of the dependencies of elements which constitute tightly correlative structures, and applied to formally define and represent tightly correlative structure. Secondly, the principle of automatic modeling of these structures was established, and the key algorithms involved such as semantic model interpretation, document creation and sub-parts mounting were elaborated. Finally, V-block assembly structure example was given to illustrate the validity and effectiveness of the approach.
Receptivity of hypersonic flow over blunt wedge under finite-amplitude disturbance wave
Tang Xiaojun, Wang Zhenqing, Meng Xiangnan, Lü Hongqing
2014, 40(5): 675-684. doi: 10.13700/j.bh.1001-5965.2013.0330
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To investigate the receptivity characteristic of hypersonic flow under the action of free stream pulse wave, a high-order finite difference method was used to do numerical simulation of hypersonic unsteady flow over a blunt wedge with slow acoustic wave in free stream. The evolution of disturbance wave modes in boundary layer was analyzed by Fourier frequency spectral analysis. Results show that different frequency disturbance modes present different changes along streamline in boundary layer under freestream pulse disturbance. Disturbance waves in the boundary layer are mainly a fundamental mode. Ranging from the nose to the non-nose, the dominant mode shifts to high frequency rapidly; while in the region far from the nose, the shift to high frequency is very slow. In general, along the flow direction the low frequency component decreases quickly; the high frequency, especially the second harmonic mode component increases. Keen competition is accompanied by energy transformation exists among different modes in boundary layer. The dominant mode has an inhibitory action on the other modes.
SIFT matching method based on support description
Zheng Hong, Liu Zhenqiang, Wen Tianxiao
2014, 40(5): 685-689. doi: 10.13700/j.bh.1001-5965.2013.0382
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To reduce the image matching errors caused by local structure similarity and other factors, a matching judgment method based on support description was proposed. An initial matching set was obtained by scale invariant feature transform(SIFT) algorithm, from which the more stable feature points were extracted to build a support feature set. According to the distribution of support feature points, a support description on the remaining feature points of the initial matching set was performed. And similarity degree between the generated descriptors was used to determine whether the feature points match correctly. After judgment the correct matching feature points were added to the support feature set, so that the support feature set expanded dynamically and distribution density of the support feature points and accuracy of the support description would be guaranteed. Experimental results show that the proposed method can preserve the correct matches while eliminating more than 90% mismatches and improve the correct matching rate effectively.
Component map correction of aero-engine based on genetic algorithm
Pan Pengfei, Li Qiuhong, Ren Bingtao, Jiang Dianwen
2014, 40(5): 690-694. doi: 10.13700/j.bh.1001-5965.2013.0333
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The components characteristic modification technology was studied. A model optimization algorithm based on changed fitness function was proposed to reduce the modeling error and improve the model accuracy. Based on the static model, characteristic correction coefficients of every component, air-entraining correction coefficients and pressure recovery correction coefficients were optimized to achieve high matching accuracy of engine model outputs to test data. The improved genetic algorithm with adaptive crossover rate and mutation rate was adopted, and the weighting coefficient in fitness function was adjusted according to the error. Then the trapping in local optimal solution was avoided and the maximum modeling error was reduced. Simulation results show that the average error of test parameters decrease from 2.420 8% to 0.321 7% after modification, and the model meets the requirements that the static error should be less than 2%.
Control characteristics analysis of drag yawing control devices of flying wing configuration
Li Zhongjian, Ma Dongli
2014, 40(5): 695-700. doi: 10.13700/j.bh.1001-5965.2013.0340
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Flying wing configuration eliminates conventional vertical tail and rudder, thus existing severe problem on yawing control. To make the configuration into practical use, it is necessary to gain an extensive understanding on the collocation features and control characteristics of yawing control devices. The current research and mechanical features of the two different kinds of yawing control devices, split drag rudder and upper surface spoiler, which are most commonly used on flying wing configuration, were introduced. Using numerical calculation, the yawing control characteristics, three-axis control coupling effect, and influencing regularities on aerodynamic and stability were analyzed. Meanwhile, the common points and differentials on aspect of control characteristics were compared. The conclusions can help to solve the yawing control problem for the flying wing configuration, and help to provide basis on engineering application for the drag yawing control devices.
Heat transfer in two-pass smooth square channel under large rotation numbers
Deng Hongwu, Cheng Junhua, Chen Hao, Tian Shuqing
2014, 40(5): 701-706. doi: 10.13700/j.bh.1001-5965.2013.0354
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The rotation number range was expanded significantly through increasing the absolute pressure of the channel to about 5 atm. Experiments were carried out to investigate heat transfers in a smooth square two-pass channel under large rotation numbers. In current study, Reynolds and rotation number range from 10 000 to 70 000 and zero to 2.08 respectively, which covered the real engine parameters. It is found that when the rotation number is large enough, the effect of rotation dominates the heat transfer at the inlet and the turn portion, instead of the entrance effect and the turn effect. As the channel rotated, the Nusselt number of the first pass was found to increase monotonically on the trailing wall, however to increase on the middle and downstream of leading wall exceeding certain critical rotation numbers. And a new phenomena is found in the downstream of the second pass, which is that the heat transfer on trailing surface exceeds the leading surface at high rotation numbers.
Performance optimization of lunar lander based on response surface methodology
Wang Jiajun, Wang Chunjie, Song Shunguang
2014, 40(5): 707-711. doi: 10.13700/j.bh.1001-5965.2013.0364
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The parametric model of the lunar lander based on multi-body dynamics was established for improving landing performances of the lunar lander. With the model, an optimal Latin hypercube experimental design for a typical failure case was carried out to find out the key factors. The sample points were acquired by using parametric model and the design of experiments to construct the response surface model, and the response surface fitting accuracy was tested. The calculated response surface results were taken as the objective functions and constraint conditions, and response surface parameters were optimized to improve the comprehensive landing performances. The optimized model was then obtained by substituting the result of the multi-objective optimization into the parametric model. Compared with the previous model, the optimized model has more excellent performance on the typical case. So that the feasibility of optimization method was verified, which can be used for the future simulation experiments.
Weld appearance of 2219- T 87 high strength aluminum alloy produced by HPVP-GTAW process
Li Yulong, Cong Baoqiang, Yang Mingxuan, Qi Bojin
2014, 40(5): 712-716. doi: 10.13700/j.bh.1001-5965.2013.0380
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Based on hybrid ultrahigh frequency pulse variable polarity gas tungsten arc welding (HPVP-GTAW) surfacing process for 2219-T87 high strength aluminum alloy, the effect of pulse current parameters on weld appearance was analyzed. Experimental results show that the weld penetration and weld depth to width was improved significantly by HPVP-GTAW process, compared with the conventional VP-GTAW process. The weld appearance was changed obviously when the pulse current parameters were adjusted. With constant average current at positive polarity duration, the weld penetration and weld depth to width was overall improved with the increase of the pulse frequency, and weld depth to width increased by 60% when the pulse frequency reached up to 60 kHz. Weld depth to width was improved with the increasing of the ratio of the pulse peak current and base current. Weld depth to width was the highest with 20% duty cycle and improved most significantly with the increase pulse current ratio compared with the duty cycle of 50% and 80%.
Grain boundary penetration behavior analysis of OFC brazed with AgCu28 brazing filler
Lian Xin, Qu Wenqing, Li Haitao, Wang Guojian
2014, 40(5): 717-720. doi: 10.13700/j.bh.1001-5965.2013.0379
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Repeated use of eutectic AgCu28 solder can cause performance degradation in the base material due to grain boundary penetration. To gain further understanding of this phenomenon, thus providing comprehensive data and technical guidance for greater reliability during production of vacuum devices, the microstructure and composition of oxygen-free copper (OFC)-Nickel-plated steel, OFC-Monel, and OFC-OFC brazed joints using AgCu28 brazing filler was observed through SEM and optical microscopy. Results show that the brazing filler in the OFC-OFC brazed joints is securely soldered to the joints' microstructure, and the microstructure is very condensed. However, the filler in the brazed joints of OFC-Nickel-plated steel and OFC-Monel diffuses along the OFC boundary, showing very apparent grain boundary penetration in the brazed joints. Ingredient analysis show that during soldering, the Ni element in Ni-containing base metal dissolves into the brazing filler rapidly. It is surmised that the dissolving of Ni element in the brazing filler is the main reason leading to grain boundary penetration.

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