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• 2012 Volume 33 Issue 3
  Published: 10 May 2012

    

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  Suspension guidingmechanism model based on roll center

  Guan Xin, Tian Lei, Pang Shuyi, Zhan Jun

  2012, 33(3): 249-254. https://doi.org/10.3969/j.issn.1671-7775.2012.03.001

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  According to the function of guidingmechanism, a suspension guidingmechanism model was built based on the roll center theory to compute the force on body by roll center concept.A suspension K&C properties correction model was also built to compensate the pose and position of wheels. A 14 DOFs vehicle model simulation code was compiled to embed the suspension model into vehicle model. An AClass Car Model was simulated to be compared with the experiment data, and to verify the correctness of the model. The vehicle handling stability was simulated to investigate the effect of suspension guidingmechanism on vehicle with step steering wheel angle input simulation as an example. The results show that the K&C parameters have great influence on vehicle, and the change trend of vehicle motion can be achieved by the simulation.
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  Analysis and experiment of frequency response characteristics of two-stage series-connected ISD suspension

  Zhang Xiaoliang, Chen Long, Nie Jiamei, Wang Ruochen, Chen Yuexia

  2012, 33(3): 255-258.

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  Based on the real analogy between inerterspringdamper mechanical system and capacitorinductorresistor electrical system, an inerterspringdamper (ISD) vehicle suspension with two stages connected in series was developed according to the principle of cascaded filter. In the suspension, the first stage is a spring in parallel with a damper, and the second stage is a parallel springdamper augmented by an inerter in parallel. A quartercar vehicle model was built to simulate and analyze frequency response characteristics of the suspension system by mechanical impedance method. A rackandpinion inerter and a prototype suspension were designed to investigate the frequencydomain performance in the suspension by bench test. The experimental results indicate that compared with conventional suspension, the improved suspension has good lowfrequency response characteristics. The frequency of body resonance is reduced from 1.3 Hz to 0.8 Hz. Improvements of 52%, 50% and 15% are achieved for peak values of gains in body acceleration, dynamic tire load and suspension working space in lowerfrequency stage. The proposed suspension can effectively suppress body resonance with improved ride comfort.
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  Efficiency model test of electric vehicle driving motor system

  Huang Wanyou1,Cheng Yong1,Li Chuang2,Zhang Xiaowen2,Wang Hongdong3

  2012, 33(3): 259-263.

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  To optimize vehicle control process according to optimal efficiency of motor system, the relationship of motor efficiency versus motor speed and torque was established. The experimental research was curried out under the work conditions measured from a real vehicle, and efficiency characteristics of the motor were obtained through a bench test. The results show that the motor system efficiency over 80% can be achieved within the range of 77.1% testing area. Electric motor efficiency data were fitted by Ordinary Least Squares (OLS). A quartic function was selected to describe the efficiency of the motor system based on the accuracy of fitting results and calculation complexity. The simulation was validated by the measured results which were obtained at full load characteristics of electric motor. The maximum relative error of 3.9% indicates that the function or model is reasonable. The proposed model can provide basis for optimizing vehicle control strategy based on the best efficiency of motor system.
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  Soot emission prediction of diesel engine with EGR

  Wang Xianli1, Wang Zhong1, Ni Peiyong1, Yuan Yinnan2, Mao Gongping1

  2012, 33(3): 264-268.

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  The oxidation model by hydroxyl group was embedded into KIVA-3V to investigate the emission of DI diesel engine and to verify the model. The effects of EGR ratios of 5%, 10%, 15%, 20% and 25% on soot emission were discussed. The results show that the calculated soot emission is good consistent with measured result. The improved oxidation model can predict soot emission well. When the EGR ratio increases, soot emission increases slightly at low load, and increases much at middle or heavy load, especially increases much more for high EGR ratio. With the increasing of EGR ratio, soot oxidation mass decreases more than soot production mass with wide distribution of high soot mass concentration. The inhibition effect of EGR on hydroxyl group is obvious at the middle stage of combustion.  When the load increases, the concentration of hydroxyl group decreases markedly with the increasing of EGR ratio.
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  Finite element analysis of high temperature pump impeller stressbased on fluidsolid coupling

  Kong Fanyu1, Wang Ting2, Wang Wenting1,Zhou Shuiqing1

  2012, 33(3): 269-273.

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  According to 2-D map of high temperature pump, the main parts of high temperature pump were modeled by Pro/E software. The fluid field of high temperature pump was numerically simulated by CFX program to obtain the pressure change at different work conditions. Based on fluid-solid coupling, stress-strain was analyzed by Ansys program at static load to investigate the deformation and stress distribution of impeller. The results show that the deformation and the distribution of stress-strain become uniform due to the symmetry of first stage. The obvious stress concentration can be found at the blade root, and diffuses to the blade outside with the increase of blade radius. The minimum stress is near to the outer margin of blade. The position of stress concentration is close to the intersection of secondary blade and hub. The maximum static stress on impeller decreases with the increase of shaft power, but with poor linear relationship.
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  Process analysis of double droplets hitting wall vertically

  Liu Hong, Wang Shuchun, Jie Maozhao, Jia Xiaojuan, Wang Yongli

  2012, 33(3): 274-277. https://doi.org/10.3969/j.issn.1671-7775.2012.03.006

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  Based on VOF method, the vertical collision process on a wall of two heptane droplets in porous media was simulated.The effects of Weber number, Reynold number, wall size and center distance of two droplets on the collision process were investigated. The dynamic characteristics of droplets collision, fusion, spreading and breaking were analyzed. Height changes of crown space film and wall membrane were obtained by changing parameters. The results show that the number of secondary droplets and the height of crown space film increase with the increasing of Weber number, Reynold number and d0/H, and also increase with the decreasing of d0/s. The height of wall membrane can be affected to some extent by changing parameters.
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  Modeling and simulation of systemic circulation system

  Qian Kunxi1, Liu Lingling1, Li Lan2, Wang Fangqun2

  2012, 33(3): 278-282. https://doi.org/10.3969/j.issn.1671-7775.2012.03.007

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  According to the equivalent relations of fluid network, electrical network, current, resistors, capacitors and inductors were respectively represented by blood flow, hydraulic viscous resistance, compliance and inertance. The left ventricle was modeled by a timevarying capacitance and myocardial impedance to establish fifthorder lumped parameter systemic circulation electric circuit model. Based on the real physiological conditions and clinical data of human being, the model parameters were determined. The hemodynamics of normal heart and failure heart caused by different part diseases were simulated to investigate the bionic control mechanism of heart failure, and to verify the feasibility of the proposed model. According to basic circuit analysis methods, the state equations were deduced and simulated by MATLAB. The results show that the modified left ventricle can comprehensively reflect the working mechanism and function of heart, and can simulate the hemodynamics of normal heart. The hemodynamics of the heart failure caused by left ventricle elastance, systemic vascular resistance or myocardial impedance can be simulated by changing model parameters.
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  Fatigue life analysis of root cutting machine blade

  Gao Dongming, Wang Decheng, Wang Guanghui, Ma Xiaogang, Yuan Hongfang

  2012, 33(3): 283-287. https://doi.org/10.3969/j.issn.1671-7775.2012.03.008

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  As a key part of root cutting machine, fatigue life of blade directly influences reliability and performance of overall machine. According to finite element method, spatial model of a rotary tiller blade was established to obtain modal and static stress analysis by Ansys Workbench. Based on the identification of the dangerous section， the stress time history of blade was determined by experiment. By the rain flow cycle counting algorithm, the stress load time history and applied stress cycle numbers were obtained. According to linear damage theory, cumulative fatigue damage was calculated by Ansys Workbench to give the distribution of blade fatigue life and dangerous section life. The method was verified  by comparison of the predicted fatigue life with experimental results.
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  SVM classification method of meat freshness based on PSO

  Liu Jing1, Guan Xiao2

  2012, 33(3): 288-292. https://doi.org/10.3969/j.issn.1671-7775.2012.03.009

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  TVB-N content, total bacterial count, pH value and sensory scores of four meat samples of pork, beef, mutton and shrimp were determined. According to support vector machine (SVM) method， the experimental data were trained to optimize the model parameters by particle swarm optimization (PSO). Based on the proposed method, the rapid and correct classification of meat freshness was realized. The experimental results show that it is difficult to obtain ideal classification accuracy by any single physicochemical or sensory property. The SVM model with RBF kernel function and default parameters can improve classification accuracy to some extent. The SVM model optimized by PSO can improve classification accuracy of meat freshness to 100% with high stability.
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  Initial rotor orientation strategy of bearingless permanent magnet synchronous motor

  Pan Wei, Zuo Wenquan, Zhu Huangqiu, Wei Jinfu

  2012, 33(3): 293-299. https://doi.org/10.3969/j.issn.1671-7775.2012.03.010

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  To realize rapid steady starting of bearingless permanent magnet synchronous motor（BPMSM）, a new initial rotor orientation method was proposed based on command current control. The suspension principle of BPMSM was given to analyze the necessary and sufficient conditions of achieving accurate position. The step angle and the positioning phase sequencer in initial orientation were optimized to identify 120° to 240° and to 0° initial orientation phase sequence. The experiments of three steps initial orientation without load were completed on BPMSM digital test rig to achieve the test wares. The results show that the orientation accuracy is controlled at the range of -1° to 1° with minimum location resolution angle of 0.2° and with motor radial displacement under 200 μm. The initial rotor orientation of BPMSM can be realized by the proposed strategy with rapid steady starting.
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  Soft sensor modeling of fermentation process based on PSO-ANN inversion

  Huang Li1,Sun Yukun2,Huang Yonghong1,Ji Xiaofu1, Wang Bo1

  2012, 33(3): 300-304. https://doi.org/10.3969/j.issn.1671-7775.2012.03.011

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  To solve the difficulty of measuring the key biological parameters on line by conventional instruments, a soft sensor modeling method was proposed based on PSO-ANN inversion to realize optimal control in biological fermentation. The mathematical model of assumed subsystem for penicillin fermentation was established to give the inverse model of fermentation. To solve the complex operation of inversion, the soft sensor method based on PSO-ANN inversion was proposed. The PSO-ANN inverse model was finally established to complete simulation and experiments. The results show that the prior knowledge and empirical data can be entirely used by the soft sensor modeling method to measure the key parameters. The proposed model shows high precision and good performance with training error of 0.037 2 and testing error of 0.046 1.
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  Parameter optimization of polymer materials degradation model based on improved PSO algorithm

  Zhang Taohong1,Zhang Ying1,2,Chen Bing3

  2012, 33(3): 305-309. https://doi.org/10.3969/j.issn.1671-7775.2012.03.012

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  To improve simulation accuracy of biodegradable polymer materials degradation model, a mathematical optimization model based on the actual principles in degradation of polymer materials and various factors was proposed. The particle swarm optimization (PSO) was used to optimize model parameters. To solve the weakness of standard particle swarm optimization algorithm, an improved algorithm was proposed to achieve optimization values. Dynamic adaptive inertia weight and asynchronous timevarying learning factors were introduced into the improved algorithm. The improved PSO algorithm was tested by five standard test functions to optimize the model parameters. The test and experiment results show that the proposed algorithm can effectively avoid being trapped in local minimum with increased accuracy and convergence rate. The simulation accuracy of biodegradable polymer materials degradation model can be significantly improved by optimized parameters. The algorithm is suitable to demonstrate the degradation mechanization and to guide the design and product of medical devices.
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  Dominancebased multigranulation rough fuzzy sets and acquisition of decision rules

  Zhai Yongjian1,2, Zhang Hong1

  2012, 33(3): 310-315. https://doi.org/10.3969/j.issn.1671-7775.2012.03.013

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   To further generalize the multigranulation rough sets approach into fuzzy information system, the basic idea of multigranulation was introduced into the dominancebased rough fuzzy set to propose dominancebased optimistic and pessimistic multigranulation rough fuzzy sets. In the two multigranulation rough fuzzy sets, a family instead of a single dominance relation was used to approximate fuzzy other than crisp target. Not only the basic properties about the proposed rough fuzzy sets were discussed, but also the problem of “OR” rules induction was investigated. A fuzzy information system was analyzed to illustrate the new proposed rough set model and acquisition of decision rules. The results show that the multigranulation rough set approach can be further expanded to deal with fuzzy data by dominance relations, and results in expanding the application of multigranulation concept.
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  Extended alarm system of marine engine room based on CAN bus

  Zhong Weibo, Ding Xiufang

  2012, 33(3): 316-321. https://doi.org/10.3969/j.issn.1671-7775.2012.03.014

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  To monitor the devices running status and improve the marine engine room environment reliability and stability in real time, an auto extended alarm system was designed based on NXP LPC1766 with CAN bus. The distributed control and double master control with hot backup and redundance structure were adopted with good manmachine interface. Based on modules, the software was designed to realize the functions of main control unit auto/manualswitching, selfmonitoring system running status, setting and acoustooptic alarm system parameters in various mode. The structures of the system hardware and software were designed to be used in several vessels successfully after functional testing, reliability testing and environmental suitability testing. The results show that the multiplex realtime alarm system can respond sound and light signals according to the predetermined rules. The system can satisfy the requirements of stability, reliability, expansibility and connectivity for modern marine engine room automation and extended alarm.
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  Optimization design for polygon blank shape based on adaptive response surface method

  Liu Yulin1,2, Chen Wenliang1, Bao Yidong1, Wang Xiaoping1

  2012, 33(3): 322-327. https://doi.org/10.3969/j.issn.1671-7775.2012.03.015

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  To mitigate the heavy simulation work of error test for blank shape, the polygon blank shape with high practical value in sheet metal forming process was optimized for design. Intelligent experiment design, moving least-square and adaptive updating method were used to establish response surface surrogate model and to optimize polygon blank shape. The corresponding optimization programs were also developed. An actual automobile side wall inner-top panel was taken as polygon blank shape for intelligent design. The optimization forming effect was compared with that without optimization. The results show that the risk of rupture and wrinkling is obviously decreased by optimization with good forming shape. The proposed method can improve efficiency and precision of optimization design with increased intelligent degree, and can speed up die design process with decreased production cost.
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  Preparation and adsorption thermodynamics of aminated-hypercrosslinked polymeric adsorbents

  Yuan Xinhua, Xu Junwei, Lei Yan, Jiang Xiao, Hu Jie, Sheng Weichen

  2012, 33(3): 328-332. https://doi.org/10.3969/j.issn.1671-7775.2012.03.016

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  Three types of aminatedhypercrosslinked polymeric adsorbents were successfully prepared. The static adsorption and thermodynamics of the adsorption for phenol and aniline onto the homemade adsorbents from aqueous solution were investigated. The results show that the adsorption capacities of phenol and aniline are both decreased with the increasing of amido content, while the decreased rate of aniline is bigger than that of phenol. The correlation coefficients are all over 099, which shows that both Langmuir and Freundlich models can well illuminate the adsorption process. The adsorption of phenol is pushed by physical and chemical interaction, while the adsorption of aniline is mainly pushed by physical interaction. Indexes of n in Freundlich regression equations are all over 1, which means that the adsorptions for both phenol and aniline are favorable adsorption. Thermodynamics data indicate that the adsorptions of phenol and aniline are exothermic and spontaneous process. The absolute value of adsorption entropy change increases with the increasing of amido content, which means that strong interaction between adsorbate and adsorbent is formed by amido.
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  Application of modified phenolic resin by nano-Al2O3 in friction materials for automotive brake

  Yao Guanxin, Hou Mingshen, Gao Dong, Liu Xingbao

  2012, 33(3): 333-337. https://doi.org/10.3969/j.issn.1671-7775.2012.03.017

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  To improve the adhesion and dispersion of nano-Al2O3 within phenolic resin and its dispersion, KH570 was used to modify nano-Al2O3. According to the analysis of transmission electron microscopy(TEM), nano-Al2O3 is uniformly dispersed in phenolic resin with optimal nano-Al2O3 content of 6 percent of phenolic resin. The effect of modified phenolic resin by blending nano-Al2O3 in friction materials was investigated with the nano-Al2O3 content of 2%, 4%, 6%, 8% and 10%. The results show that the surface-modified nano-Al2O3 uniformly disperses in phenolic resin and can significantly improve the heat-resistance of resin with nano-Al2O3 of 6%. The heat-resistance of modified phenolic resin is increased by 41 ℃ with decreased weight loss. Friction materials modified by nano-Al2O3 have stable friction coefficient and low wear rate.
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  Cavitation erosion of Cr-Ni-Mo-Cu cladding layer and 304 stainless steel

  Xu Guifang, Qin Minming, Lei Yucheng, Chen Xizhang, Li Tao

  2012, 33(3): 338-341. https://doi.org/10.3969/j.issn.1671-7775.2012.03.018

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  The Cr-Ni-Mo-Cu alloy was used as build-up welding material to investigate cavitation corrosion by TIG surface welding and to compare with that of 304 stainless steel. Cavitation erosion test of Cr-Ni-Mo-Cu material as cladding layer was conducted on an ultrasonic vibratory apparatus under artificial sea water environment. The cavitation erosion rate was measured, and the surface morphology of cladding layer was observed by scanning electron microscopy(SEM). The results show that the cavitation resistant ability of Cr-Ni-Mo-Cu alloy is better than that of 304 stainless steel. The crack initiation tends to appear at grain boundaries of alloy during cavitation，and propagate before materials spalling. The work-hardening of alloy is achieved by  the cavitation impact energy，and improves cavitation corrosion resistant ability of the cladding layer.
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  Effect of 400 ℃ annealing on strength and dislocation strengthening of Q235 steel processed by equal-channel angular pressing

  Fan Shutian, Xu Xiaojing

  2012, 33(3): 342-344. https://doi.org/10.3969/j.issn.1671-7775.2012.03.019

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  Q235 steel was quenched and subjected to equal-channel angular pressing(ECAP) processing. The effect of 400 ℃ annealing on strength and dislocation strengthening of the ECAP processed Q235 steel was investigated by tensile testing, X-ray diffractometer analysis and Taylor equation of strength-dislocation density relationship. Tensile testing indicates that the yield strength of the ECAPed Q235 steel is decreased from 825 MPa to 725 Mpa by 400 ℃ annealing, while the strain hardening capacity and ductility are obviously improved. The theoretical calculation based on X-ray diffractometer analysis and Taylor equation indicates that 400 ℃ annealing has slight influence on the dislocation strengthening. The decreasing of strength is not due to the dislocation strengthening decrease, but may due to grain boundary or subgrain boundary strengthening.
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  Experiment of initial relative density effects on sand strength

  Xu Riqing, Wang Xingchen, Zhu Feng, Zhang Jun

  2012, 33(3): 345-349. https://doi.org/10.3969/j.issn.1671-7775.2012.03.020

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  Conventional triaxial experiments of two kinds of Fujian standard sands with different gradation were performed at different confining pressure. The effects of initial relative density on shear behaviors of sand were investigated. The experimental results indicate that the initial structure has a considerable effect on shear-strength of sand. At the same confining  pressure, the initial tangent modulus and the peak deviator stress increase with the increasing of initial relative density. For the same relative density, the initial tangent modulus has a significant growth with the increasing of confining pressure, while  the peak deviator stress increases gradually. The internal friction angle of the sample shows a  linear  growth with the increase of the initial relative density. Combined with the test results, the relationship of shear strength parameter and initial relative density was established to modify Mohr-Coulomb criterion with considering initial relative density.
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  Numerical simulation on impact resistance of steel fiber reinforced high strength concrete

  Jiao Chujie, Jiang Guoping, Gao Le

  2012, 33(3): 350-353. https://doi.org/10.3969/j.issn.1671-7775.2012.03.021

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  By explicit dynamic finite element software of LS-DYNA, the split hopkinson pressure bar(SHPB) impact experiment of steel fiber reinforced high strength concrete(SFRHSC) were numerically simulated. Elastic-plastic hydrodynamic model and Hooke′s law were adopted to describe the constitutive relations of concrete and SHPB, respectively. The reinforcing and toughening effects of steel fiber on concrete were characterized by strength and failure strain of SFRHSC, respectively. The results show that internal stress of specimens oscillate initially before reaching stress equilibrium. Failure process of specimens are slightly delayed to their peak stress. The fracture of specimens matrix are more severe than that of SFRHSC specimens at any time. At the same impacting velocity, the cracks propagate in SFRHSC specimen with overall unchanged shape, while the specimens matrix are broken into many pieces. The numerical simulation results exhibite good consistency with those of experiment, and can basically reflect the characteristic of dynamic load and specimens failure during SHPB impact experiment.
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  Fracture predicting for semi-elliptic surface crack on 22NiMoCr3-7 steel plate

  Wang Zhongxian, Zhang Ruifeng, Wu Chundu

  2012, 33(3): 354-358. https://doi.org/10.3969/j.issn.1671-7775.2012.03.022

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  Based on three-dimensional elastic-plastic finite element analysis, the semi-elliptic surface cracks on 22NiMoCr3-7 pressure vessel steel plate were numerically calculated by ABAQUS software. The crack driving force of J and the crack tip constraint parameter of A2 were calculated from FEA results in the ductile-brittle transition range to describe the near crack tip stress fields. Based on J-A2 and RKR fracture theories, the ductile-brittle transition reference temperature of T0 and the crack propagation initiating spots were predicted. The results show that the maximum of J is at the deepest crack front of elliptic crack for the shallow semi-elliptic surface cracks, while that is near the crack edge for the semi-circle surface cracks. J and A2 are increased when temperature raises. The temperature effect on crack driving force of J is greater than that on crack tip constraint parameter of A2. Based on J-A2 approach and RKR fracture model, the predicting formula can well transfer the fracture toughness parameter from standard three-point bend samples to cracked structures for structural integrity assessment.
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  Influence of chloride cation type on threshold level of steel reinforcement corrosion

  Jiang Linhua1,2, Mo Lili1, Xu Jinxia1, Chu Hongqiang1, Zhang Yan1

  2012, 33(3): 359-363. https://doi.org/10.3969/j.issn.1671-7775.2012.03.023

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  To investigate the influence of chloride cation type on the threshold level for the corrosion of steel reinforcement in concrete, saturated Ca(OH)2 solution and cement extract were used as simulated concrete pore solutions. Four chloride salts of KCl, NaCl, CaCl2 and MgCl2 were used to corrode steel reinforcement. Combined the open-circuit potential with corrosion current, the initiation of pitting corrosion was detected by electrochemical impedance spectra. The results show that the chloride cation type has marked influence on the threshold level. The threshold level in saturated Ca(OH)2 solution  is decreased by Mg2+ and Ca2+ , but increased in cement extract. The threshold levels for the chloride salts with equal valent cation are the same in the two types of solution.
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  Dynamic model and stability control  of heterogeneous decisions in two-teams Cournot game

  Yao Hongxing1, Zhang Fang2

  2012, 33(3): 364-368. https://doi.org/10.3969/j.issn.1671-7775.2012.03.024

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  A two-team Cournot game consisting of two bounded rationality players and one self-adaptive player were established for adjusting the real world. The system equilibrium was calculated and analyzed by nonlinear dynamical system theory. The system dynamical behavior deduced by the change of main parameters was analyzed by the numerical simulation method. A delayed feedback control method was introduced into the system. The results show that fast changing of selfadaptive parameter can make the chaos occur in advance. It is good for the system stability if profit assignment is properly adjusted. The chaotic behavior of model can be stabilized by the delayed feedback control method
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  M／M／c queue with multiple working vacation

  Zhu Yijuan, Xu Jian, Zhou Zonghao

  2012, 33(3): 369-372. https://doi.org/10.3969/j.issn.1671-7775.2012.03.025

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  Based on the researched multi-server vacation queue， the M/M/c queue with multiple working vacation was proposed with consideration of the server wakes from energy saving mechanism to normal state in wireless communication network. All servers work at a low rate rather than complete stop during a vacation period, which means a synchronous N policy multiple working vacation. Another vacation policy of vacation interruption was introduced. Based on quasi birth and death process and matrix geometric solution method, the steady state distribution for queue length was obtained. The conditional stochastic decomposition structure of queue length was achieved under the condition that all servers were busy.