Table of Content

30 November 2017, Volume 51 Issue 11 Previous Issue    Next Issue

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Corrosion Fatigue Crack Growth Behavior of Alloy 690 in PressurizedWater Reactor Environment CHEN Kai,DU Donghai,ZHANG Lefu 2017, 51 (11):  1281-1286.  doi: 10.16183/j.cnki.jsjtu.2017.11.001 Abstract ( 910 )   Save Corrosion fatigue crack growth rates of Alloy 690 have been measured in air and simulated pressurizedwater reactor (PWR) environment, and environmental acceleration of fatigue crack growth is observed. The effects of loading parameters including loading ratio R, frequency f and amplitude of stress intensity factors ΔK have been discussed and summarized by the timedomain method. Furthermore, the obtained experimental results are compared with FA (FordAndresen) model and ANL (Argonne National Lab) empirical curve, and they could fit fairly well. Fracture surface morphology reveals tansgranular crack in air fatigue and tansgranular with intergranular crack in hotwater environment, which accords well with the description of FA model. References | Related Articles | Metrics

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Numerical Simulation on Wind Pressure and Wind Field of Chinese Ancient Buildings with MultipleEave and DoublePitch Roof WANG Xun,ZHOU Dai,LI Yu,MAO Lulu,WANG Zitong,XIANG Sheng 2017, 51 (11):  1287-1296.  doi: 10.16183/j.cnki.jsjtu.2017.11.002 Abstract ( 1015 )   Save Taking Beijing Tiananmen as an object, wind pressure and wind field around ancient buildings of tower style with multipleeave and doublepitch roof are simulated numerically by using software ANSYS Fluent and Renormalizationgroup k-ε turbulence model. The laws of wind pressure and wind field of the buildings under different wind directions are investigated. Then the influences of key parameters are indicated, including the close or open platform as well as curvature slope or linear slope of roof. The results show that wind direction has a great influence on the wind pressure of roof and double eaves. In the case of open platform, the velocity of air flow around the building reduces while negative wind pressure on the roof and double eaves decreases. Linear slope can reduce the air flow velocity at roof and double eaves and it increases the air flow velocity between double eaves. After wind pressure on the building without surrounding barrier is analyzed, wind load shape coefficients for the windresistance design of this kind of the ancient buildings are recommended. References | Related Articles | Metrics

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Research on Mechanical Properties of Locking Cap Lap Welds and Partitioned Seam Weld Model JIN Xue,ZHU Ping,LI Han,WANG Qing 2017, 51 (11):  1297-1303.  doi: 10.16183/j.cnki.jsjtu.2017.11.003 Abstract ( 1006 )   Save Locking caps are widelyused components in large engineering projects such as nuclear reactors and mining machines. In order to improve the precision of weld FE model and fatigue life prediction, it is required to obtain accurate microstructure and mechanical properties of the weld zone. In this research,the microstructure performance was studied by metallography, combined with hardness test and empirical formula to obtain stressstrain parameters of small regional organizations of the weld. Based on this, a partitioned seam weld modeling method was developed. The method was verified by quasistatic tensile test and lays the foundation for further analysis of failure mechanism and fatigue life prediction of weld zone. References | Related Articles | Metrics

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Research on Design Method of Variable Thickness Blanks for Aluminum Alloy Head Spinning Forming SONG Jinlong，ZHAO Yixi，YU Zhongqi，KONG Qingshuai 2017, 51 (11):  1304-1311.  doi: 10.16183/j.cnki.jsjtu.2017.11.004 Abstract ( 1045 )   Save ： Based on numerical simulation model of multi-pass spinning, geometry mapping relationship between the blank and spinning component was studied, and two different design methods of variable thickness blank were proposed to improve forming quality. The results showed that the two kinds of variable thickness blanks which had reasonable material distribution along the radial direction, could obviously improve the wall thickness uniformity of the spinning parts, but the variable thickness blank could also give rise to larger spinning force. By using the design method for variable thickness blank, the spinning forming experiment of aluminum alloy spherical head was completed with the good forming quality. References | Related Articles | Metrics

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Research on Prediction of Flange Wrinkling in Conventional Spinning WAN Xumin，ZHAO Yixi，KONG Qingshuai，YU Zhongqi 2017, 51 (11):  1312-1319.  doi: 10.16183/j.cnki.jsjtu.2017.11.005 Abstract ( 1107 )   Save Wrinkling is a common failure when the sheet metal is formed in conventional spinning. Hence, a lot of work has been done to accurately forecast the flange wrinkling. In this paper, the finite element simulation and experiments are established to study the deformation characteristic of the aluminum-alloy hemispherical seal head in conventional spinning, the influence of elastic strain energy and elastic strain energy increment on flange wrinkling is found, and a theoretical flange wrinkling criterion of aluminum alloy is proposed. The results show that deforming forces causes the increases and fluctuation of flange’s elastic strain energy. Due to the increasing of elastic strain energy increment’s amplitude, the unstable range appears in fan shaped area surrounded by flange edge and active region of spinning roller, and then results in flange wrinkling. This research proposes a flange wrinkling criterion based on Drucker postulate and establishes calculation process. It is proved by the experiment that this criterion can accurately predict the flange wrinkling in spinning. References | Related Articles | Metrics

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Model of Properties Prediction for Boron Steel Hot Stamping Products and Its Validation in a U-Cap Part DING Yanan，TAN Shulin，HAN Xianhong，CUI Zhenshan 2017, 51 (11):  1320-1327.  doi: 10.16183/j.cnki.jsjtu.2017.11.006 Abstract ( 973 )   Save A microstructure evolution model containing both diffusional phase transformation and non-diffusional phase transformation has been established to describe the ultra-high strength hot stamping process. A series of analytical and empirical models also have been introduced and compared to predict the hardness, strength and elongation of the final hot stamping parts, respectively. The above models were integrated in the commercial finite element analysis codes LS-DYNA, through which a U-cap part for hot stamping process was simulated, and the phase fraction and final mechanical properties were obtained. Experimental measured results show that the simulated values are acceptable and the proposed model is reliable. References | Related Articles | Metrics

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A Parametric Toolpath Design in Muti-Pass Asymmetric Spinning HUANG Yan，LU Bin，CHEN Jun 2017, 51 (11):  1328-1333.  doi: 10.16183/j.cnki.jsjtu.2017.11.007 Abstract ( 862 )   Save This paper proposes a method of generating the roller path in multi-pass asymmetric spinning process for the hollow part with straight-edge round-corner cross-section. With the principle of volume invariance, the strain distribution of general hollow part with straight-edge round-corner cross-section is analyzed under the premise of plane strain condition in conventional spinning process. The point set for each pass is generated by rationally assigning the deformation of per pass. The non-axisymmetric spinning device with independent rotation between mandrel and wheel is used to process the hollow part with three straight-edge round-corner cross-section, and the thickness distribution and spring-back of the part are measured to verify the feasibility of this method. All of the results provide a new idea for digital non-axisymmetric spinning technology. References | Related Articles | Metrics

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A Comparison Study of Different Hardening Models in Springback Prediction for Stamping of the Third Generation Ultra High Strength Steel YAN Jiawei，HU Qi，WANG Zhenzhen，CHEN Jun 2017, 51 (11):  1334-1339.  doi: 10.16183/j.cnki.jsjtu.2017.11.008 Abstract ( 1032 )   Save Serious springback and inaccurate springback prediction can lead to problems of high expenses of both money and time during the adjustment of mold. Thus, several advanced hardening models such as Swift isotropic hardening model, NSK model, Y-U model and Chaboche model were used to estimate the springback prediction of QP980 steel stamping. Software LS-DYNA which contains the four models was used to simulate the prediction, and the simulation results were compared with the experiment results. It was found that Y-U model can provide a better prediction for the springback of QP steel stamping. Y-U model can be used in the adjustment of mold so that the adjusting time and cost can be reduced. References | Related Articles | Metrics

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The Loading Path Optimization for T-Shape Tube Hydroforming Using Adaptive Radial Basis Function SONG Xuewei，MA Lingling，HUANG Tianlun，LIU Min 2017, 51 (11):  1340-1347.  doi: 10.16183/j.cnki.jsjtu.2017.11.009 Abstract ( 865 )   Save The study of surrogate model optimization of the loading path of a T-shape tube hydroforming is carried out in this paper. The adaptive optimization algorithm is introduced to radial basis function(RBF). In order to improve approximate accuracy in the concerned local regions, the paper proposes to add sample points gradually into the sample database, and to obtain the globally optimal efficiency and accuracy. The effectiveness of the method in global optimization is demonstrated by a numerical example firstly, then, adaptive radial basis function model for the T-shape tube hydroforming loading path optimization is constructed，and optimization design is carried out. The contact areas of the tube and the counter punch are selected to be the optimization target, the constraints are that the maximum thinning ratio is less than the experimental value, and the protrusion height is higher than the experimental value. The Latin hypercube design is used to obtain sample points, and the actual values of finite element analysis model of T-shape hydroforming are calculated. The loading path optimization design results are compared with the experimental values, and the result shows that the contact areas of T-shape tube and counter punch have improved by 71.912% under the condition that the minimum thickness and the protrusion height are maintained. References | Related Articles | Metrics

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Microstructure and Local Corrosion Behavior of Friction Stud Welding of 16Mn Steel GU Yanhong1,MA Huijuan1,GAO Hui1,CHE Juntie1,JIAO Xiangdong1,TIAN Lu1,2 2017, 51 (11):  1348-1354.  doi: 10.16183/j.cnki.jsjtu.2017.11.010 Abstract ( 851 )   Save In order to have a good understanding of the local corrosion behavior of 16Mn steel welded joint by friction stud welding technology, scanning vibrating electrode technique (SVET) and local electrochemical impedance spectroscopy (LEIS) were performed to investigate the corrosion current density and the impedance distribution of the welded 16Mn steel joint along stud, heat affected zone (HAZ), welded zone (WZ), another HAZ and base metal (BM). Metallographic microscope and scanning electron microscope (SEM) were used to observe the microstructure of welded joints. Residual stress in the different zones of the welded sample was measured by an X-ray stress tester. The results show that the weld zone has finer crystalline grains and denser microstructure than other zones. The residual stresses of the welded sample are shown as compressive stress, and the compressive stress in the weld zone is the smallest (-96MPa).The SVET and LEIS data indicate that the weld zone has the lowest current density (0.3霢/cm2) and the largest impedance (169k?), which may be due to the presence of the densest microstructure and the smaller residual stress in the weld zone, and shows the best corrosion resistance. References | Related Articles | Metrics

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Experimental Study on Heat Transfer Performance of Heat Pipe Grinding Wheel in High Efficiency Grinding HE Qingshan1,FU Yucan2,CUI Zhongming1,CHEN Jiajia2 2017, 51 (11):  1355-1360.  doi: 10.16183/j.cnki.jsjtu.2017.11.011 Abstract ( 1009 )   Save According to the problems of low machining efficiency and thermal damage caused by high grinding temperature for difficult-to-cut materials with high strength and toughness, a new method of improving heat transfer capacity of grinding wheel by virtue of heat pipe technology was proposed to enhance heat exchange at the contact zone and avoid high grinding temperature. On the basis of the structure of heat pipe grinding wheel and its heat transfer principle, experimental device and test method were designed and set up to investigate the heat transfer performance of heat pipe grinding wheel. Moreover, the effects of wheel speed, working fluid property, heat flux input at the evaporator, cooling condition at the condenser and liquid film thickness on heat transfer capacity and starting characteristic of heat pipe grinding wheel were analyzed. The results show that heat pipe grinding wheel can significantly increase heat exchange at the contact zone. Besides, the test method for heat pipe grinding wheel can accurately evaluate the effects of various factors on its heat transfer performance and is suitable for prediction of its heat transfer capacity. References | Related Articles | Metrics

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Research on Immunofluorescent Detection Method by Flow Cytometry Based on Bead-on-Bead Structured Particles WU Zhimin,XU Hong,GU Hongchen 2017, 51 (11):  1361-1366.  doi: 10.16183/j.cnki.jsjtu.2017.11.012 Abstract ( 962 )   Save A new type host-guest structured bead-on-bead (BOB) particle was designed and synthesized via covalent assembling guest nano silica particles onto host magnetic polymer particles. Using BOB particles as biocarrier, anti-human chorionic gonadotrophin (hCG) antibody was covalently immobilized on the surface of BOB particles. Then, the immunofluorescent detection capability in recognition hCG antigen on flow cytometry was studied and compared with traditional enzyme-linked immuno sorbent assay (ELISA). The result showed that BOB particles presented remarkable immunofluorescent detection capability on flow cytometry. BOB particles also showed excellent linear detection than traditional ELISA detection in extremely low particles amount. Further more, the limit of blank (LOB) of immunofluorescent detection on flow cytometry was nearly 1/7 to traditional ELISA detection. References | Related Articles | Metrics

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Integrated Optimization of Storage Space Allocation and Multiple Yard Cranes Scheduling in a Container Terminal Yard FAN Houming,MA Mengzhi,Yao Xi,GUO Zhenfeng 2017, 51 (11):  1367-1373.  doi: 10.16183/j.cnki.jsjtu.2017.11.013 Abstract ( 1504 )   Save In order to improve the operational efficiency and reduce the operational cost of container terminal yard, this paper studies the integrated optimization of storage space allocation and multiple yard cranes scheduling in a container terminal yard. The regional workload balance planning method is adopted to make yard working plan, and an integrated optimization model of storage space allocation and multiple yard cranes scheduling is established. It reduces the idle cost and moving cost of yard cranes considering the safety distance and workload balance between yard cranes. The simulated annealing operation is introduced to improve the global search ability of genetic algorithm. A simulated annealing genetic algorithm is designed to solve the model. The effectiveness of the adopted algorithm is verified by numerical experiments and the results show that the regional workload balance planning method can better solve the integrated optimization of storage space allocation and multiple yard cranes scheduling. References | Related Articles | Metrics

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Evaluation Approach to Rank Module Partition Schemes of Complex Products Based on Hybrid Fuzzy Multi-Attribute Decision Making LI Yupeng1,LIAN Xiaozhen1,LU Cheng1,CHU Xuening2 2017, 51 (11):  1374-1382.  doi: 10.16183/j.cnki.jsjtu.2017.11.014 Abstract ( 960 )   Save Modular development can effectively deal with the complex coupling problems of function and structure in complex products. The basis of modularization makes it difficult to obtain the single module partition scheme for complex products. To solve this problem, a module partition scheme evaluation method for complex products is put forward based on the multi-attributes decision making approach under hybrid fuzzy environment. According to the properties of the indices, by means of the interval number, intuitionistic fuzzy number, triangular fuzzy number and interval intuitionistic fuzzy number, the indices are given reasonable value assignment, respectively. The weights of the indices are determined by fuzzy analytic hierarchy process(FAHP). Distance between alternatives to the positive or negative ideal solution is calculated on the basis of the framework of technique for order preference by similarity to ideal solution (TOPSIS), and the ranking order is obtained according to the comprehensive relative closeness degree. Finally, a case study of automobile engine module partition scheme evaluation is implemented to varify the effectiveness and efficiency of the proposed approach. References | Related Articles | Metrics

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Reaction Kinetic Simulation of NOx Emission Performance for a Heavy Duty Gas Turbine LIU Aiguo1,ZHU Yue1,CHEN Baodong1,ZENG Wen1,WENG Yiwu2,LIU Kai1,WANG Chengjun1 2017, 51 (11):  1383-1390.  doi: 10.16183/j.cnki.jsjtu.2017.11.015 Abstract ( 928 )   Save The combustion process of single chamber flame tube of a heavy duty gas turbine combustor is studied by coupling of CH4 reaction kinetics model and computational fluid dynamics (CFD) software. Analysis of the causes of excessive NOx emissions is completed. The fuel distribution in different combustion zones is adjusted to study the effect of fuel distribution on NOx formation. Results show that high NOx emissions are due to high temperature caused by the fuel/air mixing ununiformity in annular and uniform zones and the fuel flow is too high in the main combustion zone. Adjusting the fuel flow of pilot zone and uniform zone respectively to 4% and 30% can increase the NOx emission from 141.7mg/m3 to 175.5mg/m3. Adjusting the fuel flow of pilot zone and annular zone respectively to 2% and 26% can decrease the NOx emission to 119.5mg/m3, in which 66.3mg/m3 is from the annular region. The requirement of NOx emissions cannot be met only by adjusting the fuel distribution, but also by adjusting the structure of the annular and uniform zones to increase mixing uniformity. References | Related Articles | Metrics

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An Online Condition Prediction Algorithm Based on Cumulative Coherence Measurement ZHANG Wei，XU Aiqiang，GAO Mingzhe 2017, 51 (11):  1391-1398.  doi: 10.16183/j.cnki.jsjtu.2017.11.016 Abstract ( 950 )   Save It is difficult for extreme learning machine with kernel (KELM) to curb kernel matrix expansion and track the system dynamic changes effectively when it is applied to solve online learning tasks. So the sliding time window method is regarded as the basic modeling strategy, and a new online sparsification learning algorithm for KELM is proposed in this paper. In the process of forward sparsification and backward sparsification, a sparse dictionary with predefined size can be selected by online minimization of its cumulative coherence based on our proposed constructive and pruning strategy. In the process of incremental learning and decremental learning, the model parameters can be directly updated by elementary transformation of matrices and block matrix inversion formula based on the selected dictionary. The performance of the proposed algorithm is compared with several well-known online sequential ELM algorithms. The simulation results show that the proposed algorithm can achieve higher prediction accuracy and better stability, meanwhile, it costs the similar testing time. References | Related Articles | Metrics

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Research on the Effects of Silt Mean Diameters and Silt Concentrations on the Cavitation Flow in a Nozzle ZHAO Weiguo1, 2,HAN Xiangdong1, 2,SHENG Jianping3,PAN Xuwei1, 2 2017, 51 (11):  1399-1404.  doi: 10.16183/j.cnki.jsjtu.2017.11.017 Abstract ( 936 )   Save The aim of this research is to study effects of silt mean diameters and silt concentrations on the evolution of cavitation. Cavitation occurring in the pure water was simulated and results were compared with experimental results to verify the algorithm employed. Silt-laden cavitation flows were simulated and laws were revealed. Results indicated that cavitation bubble with volume fraction being 0.9 is larger than pure water, when silt particles promote the evolution of cavitation. When silt particles suppress the evolution of cavitation, the cavitation bubble is smaller than pure water. With silt mean diameters being larger, scope of silt concentration promoting the evolution of cavitation shrank gradually and scope of silt concentration inhibiting the evolution of cavitation increased gradually. Results showed that silt concentrations and silt mean diameters jointly play important roles in the effects on the evolution of cavitation. Cavitation nuclei, slip velocity, viscosity and roughness have a close relation with the effects of silt particles on the evolution of cavitation. References | Related Articles | Metrics

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The Distribution for Some Certain Factorizations of the Natural Number in Arithmetic Progressions FENG Bin1,2，LIU Shuang3 2017, 51 (11):  1405-1408.  doi: 10.16183/j.cnki.jsjtu.2017.11.018 Abstract ( 756 )   Save The distribution for some certain factorizations of the natural number in arithmetic progressions was studied and an asymptotic formula was obtained by Selberg-Delange method and Perron’s formula. The formula is unconditional. References | Related Articles | Metrics