Volume 37,Issue 1,2014 Table of Contents

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  • 1  Analysis on tooth root stress and influencing factors of crossed beveloid gears with small shaft angle
    SONG Chaosheng FAN Rong LIU Libin
    2014, 37(1):1-6. DOI: 10.11835/j.issn.1000-582X.2014.01.001
    [Abstract](2033) [HTML](318) [PDF 6.19 M](1488)
    Abstract:
    In order to accurately calculate the tooth root stress of spatial crossed beveloid gears with small shaft angle, an exact geometry-based numerical computation method is proposed based on the spatial gearing theory and the finite element theory. Using the proposed method, the mathematical tooth surface model and the mesh model of a crossed beveloid gear pair with small shaft angle is created and the tooth root stress distribution is analyzed. Then the influences of the key design parameter which is the clearance coefficient, torque load, offset error, shaft angle error, pinion axial position error and gear axial position error on the tooth root stress are investigated. The results show that the increasing of the clearance coefficient can decrease the maximum tooth root stress. The root stresses distribute smoothly along the tooth width direction at a light torque load level. For heavy torque load level, the root stresses are parabolic in shape. Also, the existence of offset error and shaft angle error can increase the maximum value of the root stress obviously and the positive and negative value of the errors can change the position of the maximum root stress along opposite direction. For the pinion and gear axial position errors, they have less effect on root stress distribution.
    2  Powertrain parameter design for the electric vehicle considering driving cycle
    QIN Datong WANG Yuhan HU Minghui
    2014, 37(1):7-14. DOI: 10.11835/j.issn.1000-582X.2014.01.002
    [Abstract](2267) [HTML](960) [PDF 6.65 M](1658)
    Abstract:
    In allusion to the defects of traditional theory matching method, the authors propose a new power matching method which combines theoretic calculation and cycle working condition together for powertrain of pure electric automobiles. Based on dynamic constraint, the peak power of motor is determined. In order to make the motor work in high efficiency area, the power needed by vehicles in ten cycles is analyzed and the motor rated power is determined. Regular effect pattern of battery parameters on dynamic property and driving range of entire vehicle is analyzed. With defining a conception of acceleration time influence factor and continue driving range influence factor, motor parameters are amended. The transmission ratio is optimized with taking the power of the entire vehicle as constraint and the maximum driving range in constant speed condition as object, and the driving range is greatly improved. The output power of battery in different SOCs is simulated, and it’s found that when the SOC closes to lower limit, the output power of battery is able to satisfy the demand of the vehicle.
    3  Analysis on temperature field of pulse current discharge in metal component with double semicircle immerged crack
    FU Yuming WANG Ningning ZHENG Lijuan
    2014, 37(1):15-19. DOI: 10.11835/j.issn.1000-582X.2014.01.003
    [Abstract](1498) [HTML](293) [PDF 6.20 M](1141)
    Abstract:
    The application of crack prevention techniques is badly needed in various industries. There are many practical applications, such as in space flight and aviation, shipping, military affairs and machine manufacturing. The current density distribution, temperature field distribution of flow around the crack tip and the heat affected of two cracks are derived theoretically in view of the pulse discharge in metal component with double semicircle immerged crack. A three-dimensional finite element model with semicircular embedding crack is established by finite element software ANSYS to analyze the temperature filed. The distribution law of temperature field is consistent with the results of theoretical calculations and numerical results, and the maximum temperature error and relative error are 75.560 ℃ and 3.150% respectively. By pulse discharge experiments, the crack tip melts and passivated after pulse discharge.
    4  An analysis method of thermodynamic cycle for Stirling engine
    WANG Xinping DANG Jianjun LIU Xiaoqin
    2014, 37(1):20-25. DOI: 10.11835/j.issn.1000-582X.2014.01.004
    [Abstract](1781) [HTML](523) [PDF 5.19 M](1397)
    Abstract:
    The second-order analysis approach for the cycle of Stirling engine is amended on the basis of mechanical loss and the temperature check of heater and radiator. Stirling engine is taken as the object, the alternating flow and heat exchange process of GPU-3 Stirling engine is simulated, and the changing rules of its internal pressure, temperature, velocity, power and efficiency are obtained. The simulation results are identical to the test results of NASA. The amended second-order analysis approach is used to analyze the effect of engine’s rotating speed, working substance and average pressure on the engine’s output performance. The error of the amended approach is less than 20%. The approach may be useful for the optimization design and the characteristic analysis of Stirling engine.
    5  A calculation method of the stiffness of face gear tooth and analysis of its influence factors
    LI Zhengminqing HUANG Peng LI Xiaozhen
    2014, 37(1):26-30. DOI: 10.11835/j.issn.1000-582X.2014.01.005
    [Abstract](1604) [HTML](381) [PDF 5.23 M](1254)
    Abstract:
    Tooth stiffness of face gear is one of the components of meshing stiffness of face gear drives. Its resolve can build excellent base for calculation method of meshing stiffness and analysis of dynamic for face gear drives. Based on Buckingham’s standpoint, along the length direction of the tooth of face gear, any one of its sections can be considered as a section of rack with varying pressure angle. According to above theory, the tooth form of face gear is simulated successfully. The method of calculation of the tooth’s stiffness of face gear is obtained. Compared with conclusion of tooth’s stiffness by FEM in the same parameters, it is proofed to be correct. Through analysis of influence of tooth’s stiffness by main design parameters of face gear, the benefit conclusions are drawn. That is, the changing ratio of tooth’s stiffness decreases with the increase of module, and the tooth’s stiffness increases with the increase of pressure angle but the changing ratio almost remains constant. The tooth’s stiffness increases with the increase of tooth width and the influence of changing ratio from tooth root to tooth crest is bigger than that of pressure angle.
    6  Task decomposition and resources allocation of product collaboration innovative design
    YANG Yu LI Yunyun LI Fei XING Qingsong BAO Beifang
    2014, 37(1):31-38. DOI: 10.11835/j.issn.1000-582X.2014.01.006
    [Abstract](1457) [HTML](283) [PDF 7.17 M](1358)
    Abstract:
    To deal with the complexity problems of design tasks decomposition and allocation in the process of product collaborative innovation, a task decomposition model based on mapping level function, structure and task and fuzzy search and matching collaborative partners is proposed by considering the dependencies between the design tasks and the design capacity constraints of innovative subjects. Then on the basis of studying the classification and attributes of design resource, a design resources allocation model with resource use threshold is established to compensate the lack of resource allocation by the priority strategy for design tasks, and the simulation modeling for task-resource allocation based on the time colored Petri net is carried out. Finally, a product collaborative innovation design R & D case of a certain brand phone is imported to verify the effectiveness of the proposed model.
    7  Design of portable noninvasive detecting instrument for arteriosclerosis
    LI Songnong HE Wei YU Chuanxiang LIN Haitao LI Zheming
    2014, 37(1):39-45. DOI: 10.11835/j.issn.1000-582X.2014.01.007
    [Abstract](1737) [HTML](316) [PDF 6.61 M](1329)
    Abstract:
    The existing detecting instruments for arteriosclerosis are usually expensive and bulky. To overcome their disadvantages, a novel portable noninvasive detecting instrument for arteriosclerosis based on advanced RISC machines (ARM) and WinCE is developed and its clinical assessment experiment is carried out. Its hardware platform is an embedded system. The pulse wave signals of radial artery and brachial artery are acquired by signal measurement circuit and transmitted to ARM processor. On the basis of arterial Windkessel model and oscillometric theory, pulse wave signals analysis is performed by custom-designed software based on LabVIEW for WinCE platform, and 11 arterial stiffness assess factors are calculated. Subject’s degree of arteriosclerosis is evaluated automatically by this instrument according to these factors. The results of clinical experiment show that the instrument can accurately evaluate degree of arteriosclerosis and keep good stability and reliability. The maximum relative error of stability is 4.37%, and the correlation coefficient with the consulted instrument is higher than 0.85 (P<0.001).
    8  An asymmetric fault ride-through control method forPMSG wind turbine based onsuper-capacitors
    DU Xiong PENG Guoxiu DAI Pengcen ZHOU Luowei
    2014, 37(1):46-53. DOI: 10.11835/j.issn.1000-582X.2014.01.008
    [Abstract](1654) [HTML](306) [PDF 6.75 M](936)
    Abstract:
    With the rapid increasing interaction between wind turbines and power systems, wind turbines have to have the fault ride-through (FRT) capability to ensure the safe operation of power grid. In order to improve the asymmetric FRT capability of permanent magnet synchronous generator (PMSG) wind turbine, a novel control FRT method based on super-capacitors is proposed. In this method, super-capacitors are connected to the DC bus of AC-DC-AC converter via a bi-directional DC-DC converter, and the power processed by the super-capacitors is controlled to limit the increasing of the DC bus voltage of the AC-DC-AC converter in grid failure condition, and to reduce the 2nd order voltage ripple in the DC bus. Meanwhile, the proposed control method employs the grid voltage feed-forward approach to reduce the negative sequence current component in the grid side converter. According to the low voltage ride through (LVRT) standard, the selection of the super-capacitor capacity is also discussed, and then a mathematical model of the super-capacitor with the bi-directional DC-DC converter is established for designing the controller. Simulation results for a 1MW PMSG wind turbine by MATLAB show that the proposed control method reduces both the negative sequence current component in grid side converter and the 2nd order voltage ripple in DC link at the same time. The results also demonstrate that the asymmetric FRT capability of PMSG wind turbine is improved, which verifies the effectiveness of the proposed control method in this paper.
    9  Calculation of lumped parameter of two-port network forvolume conduction energy transfer
    TANG Zhide CHEN Xiufa LIU Hailong
    2014, 37(1):54-60. DOI: 10.11835/j.issn.1000-582X.2014.01.009
    [Abstract](1455) [HTML](763) [PDF 5.86 M](1160)
    Abstract:
    Skin electrode unit is a channel through which energy can be transferred to the implanted device by volume conduction. The unit can be equivalent to lumped circuit, but so far there are no appropriate calculation methods of these circuit parameters, so variable load method based on field-circuit coupled is proposed. A skin electrode unit field circuit coupled model is established to obtain the relationship of the network parameters between voltage and current at electrode port, and the amplitude and phase of the power signal is extracted by the use of all phase FFT spectrum analysis. On this basis, equivalent circuit impedance parameters of the skin electrode unit under various conditions are obtained by the application of variable load method and the validity of the method is verified. As a result, the equivalent circuit impedance parameters obtained in this way can be used for the circuit analysis and optimization of the volume conduction energy transfer system.
    10  Optimization of regularization parameters for electricalimpedance tomography
    CHEN Minyou HUANG Yichen LI Bing HE Wei
    2014, 37(1):61-67. DOI: 10.11835/j.issn.1000-582X.2014.01.010
    [Abstract](1461) [HTML](343) [PDF 7.44 M](1070)
    Abstract:
    The image quality and computation speed are bounded up with regularization parameters. To improve the ill-posed property of the inverse problem of electrical impedance tomography (EIT), a novel approach, which is based on the product of the residual norm and the solution norm(PRS), is presented to optimize the Tikhonov regularization parameters of EIT. To verify the feasibility and effectiveness of the proposed method, five simulations of image reconstruction, together with a tank experiment, have been carried out with considering different sizes, locations, conductivity distributions and numbers of the target areas as well as the scenarios of the data with noises. The encouraging results demonstrate that the proposed optimization approach can identify the relatively optimal regularization parameter quickly and has better noise immunity, and it also enhances the quality of the reconstructed images significantly compared with the conventional L-curve method.
    11  State of charge estimation of lithium iron phosphate batteriesbased on adaptive Kalman filters
    LIU Heping XU Qiaoqiao HU Yinquan YUAN Shanshan
    2014, 37(1):68-74. DOI: 10.11835/j.issn.1000-582X.2014.01.011
    [Abstract](2005) [HTML](482) [PDF 6.99 M](1578)
    Abstract:
    The Kalman filter algorithm can be used to estimate the state of charge (SOC) of power batteries, however, it easily causes divergence due to uncertain of system noise and its estimation performance is affected by model. An adaptive Kalman filter algorithm is adopted to dynamically estimate SOC of lithium iron phosphate batteries for application in electric vehicles. At first, an equivalent circuit model, appropriate for SOC estimation is built after studying battery models. Then some charging and discharging experiments are carried out for parameter identification and the results are verified. At last, the adaptive Kalman filter algorithm is used on this model for on-line SOC estimation under unknown interfering noise. Simulation results show that adaptive Kalman filter method can correct SOC estimation error caused by tiny model error online, and the estimate accuracy is higher than Kalman filter method. Adaptive Kalman filter algorithm can also correct the initial error. Full-cycle test in electric vehicles proves that the algorithm is appropriate for SOC estimation of lithium iron phosphate battery.
    12  Capacity analysis of steelmaking-continuous casting sectionbased on different products mixes
    LIU Qing WANG Gang WANG Bin WANG Bao XIE Feiming LI Hongwei NIE Xiaowu LU Xinchun
    2014, 37(1):75-83. DOI: 10.11835/j.issn.1000-582X.2014.01.012
    [Abstract](1169) [HTML](581) [PDF 9.07 M](1158)
    Abstract:
    Capacity is an important technical and economic indicator to evaluate the production and operating state of steel plants. Aiming at the problems about the capacity of steelmaking-continuous casting section, firstly, the operation time of steelmaking, refining and continuous casting process for different steel grades is found out by resolving the production process of a BOF special steel plant. Then, the bottleneck process under different production mixes is found by discussing the relation among the productive capacity of steelmaking-continuous casting system, the capacity of different processes and the products mixes.Finally,the improvement measures for promoting the capacity are proposed aiming at breaking through the restriction of bottleneck process. A general method to research on the capacity of steelmaking-continuous casting section is developed, which helps to determine reasonable index of products mix and give full play to the capacity of steelmaking-continuous casting section.
    13  Structure design and optimization of dual gradientnozzle used in coal mine
    LU Yiyu ZHANG Lei GE Zhaolong TANG Jiren JIA Yajie ZHANG Wenfeng
    2014, 37(1):84-90. DOI: 10.11835/j.issn.1000-582X.2014.01.013
    [Abstract](1378) [HTML](297) [PDF 8.39 M](1048)
    Abstract:
    To enhance the ability of slotted device used in coal mines, a method of re-designing and optimizing the structure of slotted device is proposed. The objective of the research is dual gradient nozzle which is installed on a 63 slotted device. Based on orthogonal experiments, the realizable k-ε turbulence model is established to simulate the output flow distribution of the dual gradient nozzle with different parameters. The results show that when the L1=6 mm, θ1=18°, θ2=35°, L=6 mm and d=2.5 mm, the axial velocity reaches its peak at 150 mm from the target and then drops slowly. Based on the simulations, experiments of ability of nozzles are made on 3DPIV in the laboratory. The results show that when the parameters are L1=6 mm, θ1=18°, θ2=35°, L=6 mm and d=2.5 mm, the average velocity of the output flow distribution has its maximum value and the velocity distribution is reasonable. The average velocity of the dual gradient nozzle at 150 mm from the target is 1.4 times of that of ordinary nozzles.
    14  The effect of original moisture content in coal beds on coal and gas outburst risk level
    JIANG Changbao YIN Guangzhi XU Jiang PENG Shoujian LI Wenpu
    2014, 37(1):91-95. DOI: 10.11835/j.issn.1000-582X.2014.01.014
    [Abstract](1875) [HTML](405) [PDF 4.33 M](1137)
    Abstract:
    By using self-made “Coal Containing Gas Thermal-Hydrological-Mechanical (THM) Coupling Experimental Equipment”, an experimental study is carried out to investigate the gas seepage law of containing-gas coal during the complete stress-strain process with different original water contents. Under the conditions of constant gas pressure and confining pressure, and the experimental results are compared with the field test of the gas emission variation of coal seams before and after being infused. The research results show that the triaxial compressive strength and the elastic ratio of coal decrease with the increase of original water content in coal, but the axial strain of coal increases and the absolute value of transverse strain and volume strain of coal increases at the triaxial compressive strength; the methane effective permeability of coal decreases throughout the complete stress-strain process. Outburst prevention by coal seam infusion attributed is analyzed from two aspects: the mechanics of coal and the gas flow in the coal seams. The higher original water content in coal seams is, the smaller the risk of coal and gas outburst becomes. So the original water content in coal seam can be treated as a significant criterion for the judgments of coal and gas outburst criticality.
    15  Elasto-plastic analysis on surrounding rock of roadways based on seepage, strain softening and dilatancy
    GAO Zhaoning MENG Xiangrui FU Zhiliang
    2014, 37(1):96-101. DOI: 10.11835/j.issn.1000-582X.2014.01.015
    [Abstract](1537) [HTML](305) [PDF 5.40 M](1301)
    Abstract:
    According to seepage body force, strain softening and rupture expansion of rock mass, elastic-plastic mechanics theory, distribution laws of stress and displacement of surrounding rock in seepage field are derived, and relationships between different zonation range of the surrounding rocks, pore water pressure, strain softening and rupture expansion are established. The results show that the pore water pressure and rupture expansion rock mass have a more obvious impact on the surrounding rock rupture area than the plastic zone. Both the plastic zone and the rupture area are larger when the seepage field is considered. The impact of strain softening on both the plastic zone and the rupture zone of surrounding rock is very significant, and both seepage and strain softening rupture expansion affect deformation of surrounding rock of roadways obviously. It provides certain reference values for the roadway support engineering in seepage field.
    16  A method of production data analysis for multi-fractured horizontal well in shale gas reservoir
    WANG Junlei WEI Yunsheng CHENG Minhua LUO Wanjing
    2014, 37(1):102-109. DOI: 10.11835/j.issn.1000-582X.2014.01.016
    [Abstract](2196) [HTML](385) [PDF 6.58 M](1293)
    Abstract:
    Production data analysis is an effective method of evaluating gas in place, parameters of reservoir and hydraulic fractures. Current model of production data analysis fails to make sense because of the existence of absorption, multi-fracturing, and stimulated reservoir volume (SRV). Considering the effect of desorption, fracture interacting and closed boundary, the authors calculate the productivity of multi-fractured horizontal well in shale gas by Laplace transform and pressure superposition principle. Then theoretical charts of Agarwal-Gardner production decline curves are presented by employing new definition of dimensionless material balance time and dimensionless production, which is based on asymptotic approximations. The result shows that Agarwal-Gardner curves can be divided into two parts where they are scattered in early transient period, and where their shape was influenced by parameters relevant to adsorption, position of each fracture and reservoir geometry, and then drawn to Arps harmonious decline in pseudo steady state period. Reservoir parameters, hydraulic fracture characteristics and gas in place are evaluated by using the type curve matching with actual production data.
    17  Determination of cationic degree in cationic polyacrylamide P(AM-DAC)
    ZHENG Huaili MIAO Shuxiang ZHU Junren ZHU Chuanjun JI Fangying LIU Liwei MA Jiangya SUN Yongjun LI Peiwen
    2014, 37(1):110-116. DOI: 10.11835/j.issn.1000-582X.2014.01.017
    [Abstract](1867) [HTML](751) [PDF 5.66 M](1529)
    Abstract:
    The precipitation titration method and colloid titration method are respectively used to determine the cationic degree of cationic polyacrylamides P (AM-DAC) samples that are self-prepared in the laboratory. And mathematical method is used to comparatively analyze the two methods. It is found that both precipitation titration and colloid titration can accurately measure cationic degree, but the colloid titration method is more stable and accurate than precipitation titration method. The influence of different factors on the colloid titration are also analyzed in experiments, and the experimental results show that the measured value of cationic degree is the closest to the theoretical value when the pH value is within the range of 1.75 to 2.2, the titration rate in the range of 0.01 mL/s to 0.05 mL/s, and the titrimetric solution concentration in the range of 1×10 -4 g/mL to 2×10 -4 g/mL.
    18  The chloride mask in COD determination of pickled mustard wastewater with high salt
    GUO Jingsong LIN Jiaqi FANG Fang ZHU Youli BAO Zhenguo
    2014, 37(1):117-122. DOI: 10.11835/j.issn.1000-582X.2014.01.018
    [Abstract](2036) [HTML](560) [PDF 4.80 M](1143)
    Abstract:
    Chlorides in the wastewater with high salt seriously interrupts the determination of chemical oxygen demand(COD). Therefore, chloride mask in wastewater has been an important and difficult issue in recent years. In the present work, experiment design is used for more accurate and precise COD determination method of pickled mustard wastewater. Two methods for masking chloride are adopted: HgSO4 masking method and AgNO3 masking method. After masking chloride, use the traditional reflux digestion method to test COD in the experimental sample. The results show that when the ratio of HgSO4 to Cl - is 40, the chloride mask results in a minimum error of 1.43%, and the minimum error is 0.21% when AgNO3 is used. Obviously, AgNO3 masking method is superior to HgSO4 masking method. However, when these two methods are used in pickled mustard wastewater, there is a COD value difference of 20 mg/L and HgSO4 masking method is more accurate. By considering the characteristics of the two methods above, a combined method is proposed, which AgNO3 is added equivalently according to the concentration of Cl - first, and then a few amounts of HgSO4 are added to prevent the free Cl - in wastewater. The facts show that combined method is more reliable.

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