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15 August 2012, Volume 31 Issue 4 Previous Issue    Next Issue

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Geometric Nonlinear Analysis for Prestressed Tendons on Bonded Prestressed Concrete Beam Deng Ji-hua ,Shao Xudong,Liu Haibo 2012, 31(4): 739-742.  DOI: 10.3969/j.issn.1674-0696.2012.04.01 Abstract ( )   PDF (252KB) ( )   In order to solve the problem of the references for the geometric nonlinear analysis of prestressed concrete plane beam element，based on the conventional nonlinear balance equation of beam，prestressing tendon is regarded as truss element with rigid arm and prestressing force is taken into account in local coordinate system ( co-rotational coordinate system) ． According to the characteristics of the motion and deformation of rigid arm，geometric nonlinear tangent stiffness matrix of truss element with rigid arm in global coordinate system is acquired，a more exact expression of tangent stiffness matrix for composite elements is also derived for prestressed concrete plane beam． A computer program is developed to analyze the geometrical nonlinear behavior of a prestressed concrete cantilever beam． The results demonstrate that the proposed innovative element and algorithm are efficient and accurate together with satisfied convergence． References | Related Articles | Metrics

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Deviation Reinforcement Analysis of Curved Steel Box Girder Bridge Deng Na, Jiang Chang-sen, Jiang Ling-qiao 2012, 31(4): 743-746.  DOI: 10.3969/j.issn.1674-0696.2012.04.02 Abstract ( )   PDF (185KB) ( )   The creep deformations of curved girder bridge often occur． This paper makes a deviation rectifying research on lateral and torsional distortion of simple-supported continuous curved steel box girder bridge． By using FEM software MIDAS， the combined construction scheme of vertical and lateral thrusting is determined to rectify the curved beam． The construction process is optimized according to the characteristic of curved beam． Respectively methods are presented to caculate the thrusting force． The construction scheme is proved to be reasonable and practical in the practice References | Related Articles | Metrics

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Study on Two-Dimensional Damage Identification of T-Beam Based on Gaussian Curvature Mode Difference Han Xi,Li Qing-da,Zhong Li,Yang Ke 2012, 31(4): 747-750.  DOI: 10.3969/j.issn.1674-0696.2012.04.03 Abstract ( )   PDF (276KB) ( )   Curvature mode is a sensitive indicator to identify damage． Most researches on damage identification based on curvature mode are limited to one-dimensional structure． Damage identification based on Gaussian curvature mode was presented to extend curvature mode into two-dimensional structure，considering the degree of bending about two-dimensional structure of acceleration mode shape in the vertical level and horizontal level and locating the position of damage by calculating the Gaussian curvature difference of acceleration mode of structural damage on before and after． Mode test of the combination of T-beam structure and its results analysis show the feasibility of the proposed method． References | Related Articles | Metrics

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Analysis of Stress on Cable-Beam Anchorage Zone for Cable-Stayed Bridge Wang Shao-huai,Xiang Zhong-fu,Xie Bing-min,Zhao Jun 2012, 31(4): 751-754.  DOI: 10.3969/j.issn.1674-0696.2012.04.04 Abstract ( )   PDF (312KB) ( )   By using the ANSYS，a 3-dimensional finite element model for the cable-beam anchorage zone of Fenfangwan Bridge was built to investigate the stress． The stress distribution was analysed and the bearing capacity was consequently evaluated． The following conclusions can be drawn: the stress on ear-plate is much greater than the other plates; the maximum Mises stress is located on the sides of pin hole; stress transfers fast and fluently though it is greater on some local regions; the structure could meet the requirements of bearing capacity． References | Related Articles | Metrics

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Effect of Cross Section Type of Tunnel Anchorage on Its Mechanical Behavior for Suspension Bridge Jiang Nan,Feng Jun 2012, 31(4): 755-759.  DOI: 10.3969/j.issn.1674-0696.2012.04.05 Abstract ( )   PDF (289KB) ( )   Comparison of the displacements and bearing capacity of these two cross section types were performed by using finite element method with ABAQUS． The surrounding rock and anchorage were simulated by 8-node 3D brick elements． Interface between the surrounding rock and anchorage was modeled by contact element． A extended Mohr-Coulomb model was adopted for the rock mass． Over-loading method was applied to calculate the ultimate bearing capacity of anchorage． The results show that for U-type cross section，stress concentration occurs at the arch，while the stress distribution around the circular cross section is uniform． In case of identical section area and cable force，the displacement of circular tunnel anchorage is less than U-type tunnel anchorage by 22%． The ultimate bearing capacity of circular anchorage is larger than U-type anchorage by 18%． References | Related Articles | Metrics

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Construction Control Program Development for Superstructure Suspension Bridge Based on Analytical Method Liu Jia-min,,Cui Ying-ming,Xiao Jun,Zhang Yong-shui 2012, 31(4): 760-763.  DOI: 10.3969/j.issn.1674-0696.2012.04.06 Abstract ( )   PDF (268KB) ( )   The calculation principle and process of the construction control special program for suspension bridge superstructure were introduced based on analytical method; the analysis program MKJS for the anchored span strand of suspension bridge was improved; the SBCC3． 0 was developed through the programming languages of Fortran and Visual Basic，which can meet the needs of the construction control calculation for suspension bridge superstructure． References | Related Articles | Metrics

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Contrast of Wave and Vibration Methods for Underground Structure Gao Feng,Sun Chang-xin,,Zhao Feng-bing 2012, 31(4): 764-768.  DOI: 10.3969/j.issn.1674-0696.2012.04.07 Abstract ( )   PDF (284KB) ( )   Calculation theories and methods are introduced respectively in this paper; artificial seismic wave was calculated by wave method and vibration method respectively and the difference of these two methods has been analyzed． The analytical results indicate that: the calculating values and changing rules of wave method and vibration method are almost accordant; the wave method can reflect the time effects for the transition of wave while the vibration method cannot; the vibration method has the following advantages: its calculating steps are simple; its calculating precision can meet the needs． Therefore，vibration method is suggested to be used for the dynamical analysis of underground structure． References | Related Articles | Metrics

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Analysis of Difference in Axial Force of Anchor in Loess Tunnel with Large Cross-Section Su Zhong-ming,Sun Zhi-jie,Wang Xiao-feng 2012, 31(4): 769-771.  DOI: 10.3969/j.issn.1674-0696.2012.04.08 Abstract ( )   PDF (159KB) ( )   Based on the Hejiazhuang tunnel on the Zhengzhou-Xi’an passenger dedicated railway， forcing cases of systematic anchor was studied in loess tunnel with large cross-section and forcing characteristics of systematic anchor at vault and sidewall parts were obtained; reasons why the forcing difference varies much were analyzed from the perspective of the law of radial displacement attenuation and distribution form of surrounding rock pressure; the related conclusions will offer reference value and guiding significance to the design and construction of such tunnels． References | Related Articles | Metrics

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Application of Pedestrian Simulation Software on the Emergency Evacuation at Light Rail Station Wu Xiao-kang,Zhou Li-feng 2012, 31(4): 772-776.  DOI: 10.3969/j.issn.1674-0696.2012.04.09 Abstract ( )   PDF (366KB) ( )   The microscopic pedestrian traffic simulation software Legion，which is based on the theory of social force model， can simulate emergency evacuation at the light rail station，and get the maximum emergency evacuation time required by the station staff． Therefore，we can visually and quantitatively analyze the ability of the light rail station to deal with emergency cases，which can help to guide and adjust to the planning and design，evaluate the design project，plan the organization scheme，and conduct the emergency evacuation pre-arranged planning，etc． ． It can help to assist the design，the operational decision-making and the organizational management of the light rail station． References | Related Articles | Metrics

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Test on Dynamic Response of Flexible Base Asphalt Pavement Li Qi-wei,Li Xiao,Liang Nai-xing 2012, 31(4): 777-780.  DOI: 10.3969/j.issn.1674-0696.2012.04.10 Abstract ( )   PDF (215KB) ( )   According to repeated load test of flexible base asphalt pavement，the structure is built in the indoor pit． The principle of choosing resistance strain gauges and the surface-sticking process of gauge was summarized; the survival rate of strain gauge based on the comparison of road roller’s compaction mode strong vibration or static pressure was discussed． The data of time-history curves was collected through the Wheatstone Bridge with the numerical calculation comparative study． The detection results show: the gate length of resistance strain gauge should not be less than 80mm，which is related to nominal maximum size of aggregate． Gauges’survival rate is affected by different compaction model，which is much lower under the strong vibration model． Also the response of strain in layer bottom under the dynamic load of moving vehicle is more complex than that in static situation． However，the current pavement structure design method needs transforming from static model to dynamic load model． References | Related Articles | Metrics

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Relevance of Dynamic Shear Rheometry Parameter of Fiber Asphalt Binder and Temperature Yao Li-yang,,Yao Li-hong,Ma Qin 2012, 31(4): 781-784.  DOI: 10.3969/j.issn.1674-0696.2012.04.11 Abstract ( )   PDF (179KB) ( )   Dynamic shear rheometry test was used to analyze relevance of dynamic shear rheometry parameter of fiber asphalt binder and temperature，and temperature sensitivity of different parameter and different fiber asphalt binder． The result shows that the parameters including G* ，G'，G″，G* /sin δ and δ，have close connection with temperature． Temperature sensitivity of all parameters in lower temperature areas is higher than that in higher temperature areas． Temperature sensitivity of fiber asphalt binder is significantly decreased in comparison with normal asphalt; the heating stability of polyacrylonitrile fiber binder is better． Rut-resistance factor G* /sin δ of fiber asphalt binder increases greatly． This shows that anti-deforming capability of fiber asphalt binder is significantly enhanced． References | Related Articles | Metrics

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Study on Surface Texture of Exposed-Aggregate Cement Concrete Pavement Based on Digital Image Technique Song Yong-chao,Li Fu-chun,Liang Nai-xing 2012, 31(4): 785-787.  DOI: 10.3969/j.issn.1674-0696.2012.04.12 Abstract ( )   PDF (162KB) ( )   The exposed-aggregate surface of EACCP possesses some advantages，such as big stiffness，high slide，low noise， anti-glare，etc． By using basic method of digital image technique，the image pixel values of the exposed-aggregate surface are quantitatively calculated． The relational model between the average of pixel difference and surface texture depth is established． According to large numbers of digital images on the EACCP，the surface texture depth of corresponding sites is calculated． Finally， exposed-surface structure quality of EACCP can be evaluated． Application Example shows that method of digital image technique can quickly test surface texture depth of EACCP，and can be easy to achieve measurement of continuous work． References | Related Articles | Metrics

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Experimental Study on the Fracture Toughness KICof Soil Liao Pei-wei,Tang Hong-mei 2012, 31(4): 788-791.  DOI: 10.3969/j.issn.1674-0696.2012.04.13 Abstract ( )   PDF (320KB) ( )   Conventional three-point bending test， the loading direction and the gravity direction of the sample are in the same line． Because of the low tensile strength of soil，the sample will break only under the sample deadweight at the three-piont test of soil． Even if the sample is not broken，the deadweight will exert a great influence on the test results． According to the principle of three point bending test，the sample along the bottom edge to rotate 90°，by using horizontal loading way，the deadweight of sample is vertical to loading direction． In this way，the effect of gravity on the test results is avoided． The fracture toughness of soil is obtained by breaking assembly of soil which is independently developed． References | Related Articles | Metrics

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Large-Sized Triaxial Test on Reinforced Soil with Geogrids Zhou Bin,Zheng Zhi-neng,Ling Tian-qing,Yang Bo 2012, 31(4): 792-794.  DOI: 10.3969/j.issn.1674-0696.2012.04.14 Abstract ( )   PDF (268KB) ( )   A novel triaxial instrument was employed to test the characteristic of large-sized reinforced soil sample． The sample is 30 cm in diameter，60 cm in height，and two layers of geogrid were put into it． Stress-strain relationship，shear shrength and the influence of moisture content on physical properties of reinforced soils were achieved by the test established ahead． References | Related Articles | Metrics

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Research Progress on Determination of Resilient Modulus of Subgrade Soils in U．S． Zhang Xiao,Zhao Dui-jia,Liu Shao-wen,Shen Jun-min 2012, 31(4): 795-798.  DOI: 10.3969/j.issn.1674-0696.2012.04.15 Abstract ( )   PDF (158KB) ( )   Resilient modulus of subgrade soils，representing the mechanical parameters of subgrade soils strength，is the main design parameter for the pavement design． It plays an important role in pavement surface deflection pavement designed thickness． The research progress of the laboratory test methods of dynamic resilient modulus of subgrade soils，constitutive models and field experiment methods in U． S． has been reviewed． Comments on current research status and future research directions were presented． References | Related Articles | Metrics

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Research on Dynamic Stress of Subgrade Soil under Vehicle Loads and Its Diffused Rule Liu Wei,Tang Lian-sheng,Zhang Qing-hua 2012, 31(4): 799-802.  DOI: 10.3969/j.issn.1674-0696.2012.04.16 Abstract ( )   PDF (241KB) ( )   It put forward a method to calculate vertical dynamic stress of the subgrade under vehicle loads． Vertical stress of the subgrade soil under moving loads is different from the stress under inmobile loads，which can be described by“speed coefficient” and its value is 0． 105． The dynamic stress on the top of the subgrade caused by the vehicle loads varies from 0 kPa to 16 kPa，and it will decrease as depth increases． When the depth of subgrade soil is more than 8m，the dynamic stress caused by vehicle loads is less than 10 percents of the stress on the top of the subgade soil． As the vehicle loads is bigger，the vertical dynamic stress diffuses slower． References | Related Articles | Metrics

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Wireless Remote Health Monitoring of Mountainous Highway Subgrade along Reservoir Bank Based on GPRS Yan Zong-ling,Yang Jing,Li Hai-tao,Jiang Zhong-ming 2012, 31(4): 803-806.  DOI: 10.3969/j.issn.1674-0696.2012.04.17 Abstract ( )   PDF (239KB) ( )   The key parameters are chosen since highway subgrade is linear engineering，and monitoring points are distributed widely and dispersively． A remote health monitoring system is set up based on GPRS technique which provides long distance wireless transmission of health monitoring data for mountainous highway subgrade along reservoir bank． Health of subgrade along reservoir bank is analyzed and potential disease is discovered timely which provide scientific basis for construction decision， safety operation and subgrade disease preneention and control． References | Related Articles | Metrics

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Study on Threshold of Work Zone Simulation Analysis Based on Orthogonal Experiment Zhang Hui-ling,Liu Wei,Zeng Hao 2012, 31(4): 807-810.  DOI: 10.3969/j.issn.1674-0696.2012.04.18 Abstract ( )   PDF (177KB) ( )   The paper studies the Four-lane’s traffic impacting analysis threshold when the road is working． Four factors and three levels are chosen based on the possible impacting factors． The orthogonal experiment is used to get the experiments’ combination; the VISSIM software is used to get the experiment scene． Based on the simulation model，the order of the factors impacting the traffic is closed lane number，the saturation，the bus ratio and the work zone length． For the interaction phenomenon of the closed lane number and the saturation，when there are two or three closed lanes，the simulation scene is made again and the saturation is increased gradually． Finally，the threshold is got． References | Related Articles | Metrics

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Application of Ground Penetrating Radar on Detecting Voids of Pavement Wang Wen-shan,Xiang Yang-kai,Xiong Chao-bo 2012, 31(4): 811-814.  DOI: 10.3969/j.issn.1674-0696.2012.04.19 Abstract ( )   PDF (233KB) ( )   The basic tenets of the ground penetrating radar detection method were introduced; based on the engineering practice， the ground penetrating radar detection method was used in the cavity detection of cement concrete slabs． Firstly the test points were selected and radar’s parameter was accommodated; then the radar’s detection data which was coped with software could directly judge the position of the road’s voids，read the length and height of cavity，and obtain the preliminary judgment of the cavity reason． The data shows that the radar’s cavity detection，compared with the falling weight deflectometer’s has higher reliability; with the help of drilling core，the data’s accuracy of cavity detection can reach more than 80%． References | Related Articles | Metrics

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Optimization and Precision Evaluation with GPS Elevation Fitting Method Based on Neural Network Qiang Ming,Guo Chun-xi,Zhou Hong-yu 2012, 31(4): 815-818.  DOI: 10.3969/j.issn.1674-0696.2012.04.20 Abstract ( )   PDF (202KB) ( )   According to current elevation fitting methods of networks，the genetic algorithms( GA) and particle swarm optimization( PSO) methods were employed to optimization of the weights and threshold of BP neural networks; with evenly distributed GPS data，GPS elevation fitting based on neural network is calculated． The fitting results show that optimization of the BP neutral network by PSO is better than that by GA and the error is relatively small． References | Related Articles | Metrics

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Differences between Activity-on-Arrow Network and Activity-on-Node Network Based on Dummy Activity Wei Daos-heng 2012, 31(4): 819-823.  DOI: 10.3969/j.issn.1674-0696.2012.04.21 Abstract ( )   PDF (256KB) ( )   The difference between activity-on-arrow network and activity-on-node network is the symbol exchange，which brings the variations on the time index calculation and critical path． These variations are caused by the dummy activity in activity- on-arrow network; hence，the main difference between activity-on-arrow network and activity-on-node network lies in whether the dummy activity exists in activity-on-arrow network． Taking an example，the differences are caused by the dummy activity． Dummy activity is important in the application of network planning． References | Related Articles | Metrics

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Regional Traffic Modal Splitting Method Based on Improved MD Model An Wen-juan,Chen Feng 2012, 31(4): 824-827.  DOI: 10.3969/j.issn.1674-0696.2012.04.22 Abstract ( )   PDF (369KB) ( )   With analysis of the basic principles of the MD model and consideration of factors like travel time，cost，safety ， convenience，comfort on travel mode choice，this paper improved quantitative method of travel to sacrifice and joined the se- curity，comfort and convenience of quantitative indicators to quantitative methods． Then MD regional traffic mode split model based on improved forecasting methods was established，and a prediction model in the forecasting process and key variables algorithm was given． Thereafter the validity and practicability of the proposed method was demonstrated by the examples of traffic mode split of Shanghai-Nanjing corridor References | Related Articles | Metrics

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On K-nearest Neighbor Short-Term Traffic Flow Prediction Fang Qin,Li Yong-qian 2012, 31(4): 828-831.  DOI: 10.3969/j.issn.1674-0696.2012.04.23 Abstract ( )   PDF (197KB) ( )   Traffic flow prediction was analyzed from characteristics; the method of K-nearest neighbor was applied in the non-parametric regression for short-term forecast of road traffic flow; the road traffic-related data of Guiyang City was employed to validate the model． It proves that the K-nearest neighbor nonparametric regression model can predict the shortterm traffic flow more accurately and it also reveals that the feasibility of the methods is used in short-term traffic flow prediction． References | Related Articles | Metrics

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Short-Time Prediction of Traffic Flow on the Basis of PSO-SVM Wang Shu-yang,Huang Tian-min,Fang Xin 2012, 31(4): 832-835.  DOI: 10.3969/j.issn.1674-0696.2012.04.24 Abstract ( )   PDF (188KB) ( )   Parameter selection for SVM exerts influence on the predicting function of SVM prediction model in traffic flow． The present paper introduces PSO optimization mechanism to solve parameter selection of SVM． The way is to select SVM training parameters by PSO; then better PSO-SVM prediction model is obtained． Finally the paper compares PSO-SVM prediction model with neural network by means of simulation experiments and shows that PSO-SVM prediction model has advantages over neural network． References | Related Articles | Metrics

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Research on Minimum Bus Headways Calculating Model Based on Solving High-Frequency of Bus Operation Zhou Jia-nan,Luo Xia,Huang Qi-le,Wei Qiang 2012, 31(4): 836-841.  DOI: 10.3969/j.issn.1674-0696.2012.04.25 Abstract ( )   PDF (255KB) ( )   A method was provided for setting the minimum bus headways in order to solve the high-frequency of bus operation with the target of realizing the minimum operation costs and maximum benefits of passengers based on description of high-frequency of bus operation and analysis of the causes． This model has been applied to the No． 81 Route bus in Chengdu by surveying data and proved to be feasible and effective． References | Related Articles | Metrics

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Research on Chaos Particle Swarm Optimization Algorithm for Vehicle Routing Problem Li Yi,Lu Bai-chuan,Liu Chun-xu 2012, 31(4): 842-845.  DOI: 10.3969/j.issn.1674-0696.2012.04.26 Abstract ( )   PDF (164KB) ( )   According to characters of the vehicle routing problem，a novel chaos particle swarm optimization( CPSO) algorithm was proposed to solve the basic type of single depot and non-full load． After the chaos was introduced to the particle swarm optimization( PSO) ，the random，regularity and ergodicity were used to initialize particles in order to cover the solution space of the vehicle routing problem in large range，enhance the ability for optimal route searching，and prevent the suboptimal solution of the PSO in the way of exerting chaos disturbance at the place of suboptimal solution to help algorithm to abandon the current searching route． Illustration results showed the CPSO had the strong ability to search the global optimal in the vehicle routing problem． References | Related Articles | Metrics

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Analysis of Traffic Safety Evaluation Model for Expressway Zhao Yuan,Yao Hong-yun,Yan Dong-mei,Long Dong-hua 2012, 31(4): 846-851.  DOI: 10.3969/j.issn.1674-0696.2012.04.27 Abstract ( )   PDF (168KB) ( )   Highway traffic safety score model is established to more effectively carry out a real-time traffic warning． A new definition of the speed dispersion is introduced to analyze the relationship between the new definition of speed dispersion and conventional dispersion-standard deviation of speed，which indicates a function relationship between the two． Factors such as speed dispersion，driver，road，vehicle and climate，constitute six major indicators of the driver-vehicle-road-the road alignment- climate-vehicle status; the sub-indicators of the major indicators are selected; a corresponding evaluation index system is established． The weight of each parameter is calculated to build the model by AHP． After being verified by example，it is indicated that the model is in line with objective reality，therefore it has certain feasibility． References | Related Articles | Metrics

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Collection and Analysis about Background Factors of Road Traffic Accidents Index Deng Ming-yang,Fu Rui,Chen Guang-jiao 2012, 31(4): 852-856.  DOI: 10.3969/j.issn.1674-0696.2012.04.28 Abstract ( )   PDF (320KB) ( )   This paper proposed the concept of accident background factors，established index system of background factors and collected data． Therefore，it constructed the complete database design scheme of the background factors，as well as established the statistical analysis system of background data fitting in with our country analysis model of road traffic accidents background． In order to grasp the overall road safety situation and development trend，the main background reason which caused accidents was found out; safety countermeasures were extracted，which provided the scientific basis for adoptting scientific and effective road traffic safety measures． References | Related Articles | Metrics

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Finite Element Numerical Simulation of Deformable Barrier in RCAR Test Wang Li-zhen,Chen Kun-shan,Hong Liang 2012, 31(4): 857-861.  DOI: 10.3969/j.issn.1674-0696.2012.04.29 Abstract ( )   PDF (345KB) ( )   According to the latest RCAR Bumper Test，a three-dimensional geometric model of the barrier was built． The 3- D model was meshed in HYPERMESH and then imported to ANSYS． The performance quasi-static test of the model under perpendicular loading and eccentric loading was simulated in ANSYS． The results show that the model deforms reasonablely under both loading conditions，and the forces and deflections fall within the corridors required in the regulation． The built finite element model can meet the requirements in the test， and can be used in the following research of bumper virtual experimental platform． References | Related Articles | Metrics

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Uncertainty Measurement of an Electrical Measuring System Based on Vehicle Crash Test Chen Shuang,,Sun Hao,Ren Pei 2012, 31(4): 862-865.  DOI: 10.3969/j.issn.1674-0696.2012.04.30 Abstract ( )   PDF (214KB) ( )   The data and error transfer paths of electrical measuring systems in vehicle crash test were analyzed; the uncertainty measurement of an electrical measuring system constituted by a PR accelerometer and a multi-channels data acquisition system was studied． Influences of subsystem on the overall system uncertainty were analyzed; the measurement uncertainty of electrical measuring system was evaluated according to regulations． The study could provide practical references for the measurement uncertainty evaluation of data channel in GB11551． References | Related Articles | Metrics

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Crashworthiness Numerical Simulation of Material Properties on Vehicle Steering Mast Song Xiao-hua,Li Wei 2012, 31(4): 866-868.  DOI: 10.3969/j.issn.1674-0696.2012.04.31 Abstract ( )   PDF (269KB) ( )   Due to the fact that drivers are usually hurt by vehicle steering mast in a frontal collision，a vehicle steering mast is studied based on the explicit dynamics finite element method． The finite element model of steering mast is developed． According to the request of collision，the steering mast with different materials including mild steel，alloy steel and high strength steel is investigated． The deformation pattern，displacement，velocity and energy absorption are discussed． The results show that the deformation pattern，deflection，crash time and energy absorption of the alloy steel and high strength steel are better than those of the mild steel． The vehicle steering mast with different material exerts influence on collision performance． References | Related Articles | Metrics

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Analysis of Damage Degree of Vehicle Based on Assemble Model Yang Ya-yi,Zhang Fu-ren 2012, 31(4): 869-872.  DOI: 10.3969/j.issn.1674-0696.2012.04.32 Abstract ( )   PDF (168KB) ( )   Based on used vehicle technology assessment，the paper aims to give reference for customer． The synthetic evaluation system of second-hand car depends on static check，dynamic check and instrument check，including five elements: appearance，engine，inner and electric equipment，performance． Entropy method was employed to determine the weight of indexes; an evaluation model of the damaged degree of used vehicle was built based on Grey relation degree theory． The results show that the theory of evaluation model is succinct，convinient and operable． Therefore it is valuable and could provide references for revising the standard of scrapped car． References | Related Articles | Metrics

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Changes of Annual Runoff Distribution in Upper Streams of Yangtze River Basin Wang Miao-lin,Hou Bao-jian 2012, 31(4): 873-876.  DOI: 10.3969/j.issn.1674-0696.2012.04.33 Abstract ( )   PDF (146KB) ( )   In this paper，indexes of concentration，concentration period，unevenness and variation have been defined and calculated according to gauge records of runoff at the main station in the upper streams of the Yangtze River Basin． The main stations include the Pingshan Station on the Jinsha River，the Gaochang Station on the Minjiang River，the Beibei Station on the Jialing River，the Cuntan Station on the upper Yangtze River and the Wulong Station on the Wujiang River． And then the changes of annual runoff distribution in the upper streams of the Yangtze River Basin have been discussed． The results show that the unevenness of Beibei Station is greater than the other stations; the concentration unevenness of Beibei Station is the greatest and Wulong Station is the smallest． The concentration period of Wulong Station is in late June and in the other station is in July or August． The relative variation rate of Beibei Station is the greatest and Pinshan Station is the smallest． The inter-annual changes of annual runoff distribution were further analysed by the Kendall＇s rank correlation method． The results show that the unevenness，concentration and relative variation rate decreased obviously． The conclusions are meaningful for water resources management in the upper streams of the Yangtze River Basin． References | Related Articles | Metrics

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Study on the Navigable Hydraulic Parameter of 3000-ton Ships at the Rapids of Three Gorges Reservoir Area Zhang Peng,Hu Jiang 2012, 31(4): 877-880.  DOI: 10.3969/j.issn.1674-0696.2012.04.34 Abstract ( )   PDF (225KB) ( )   In the impoundment stage of Three Gorges reservoir，the improved conditions of navigation have played an important role in promoting the economic development of the upstream region． In the flood period，however，the rapids contained the promotion of reservoir navigation capacity due to the rapid flow． The 3000-ton ships are mainly navigation ships of Three Gorges Reservoir Area． However，there is no research about it． Therefore，this article was based on the actual measurement when the 3000-ton ships traveled the rapids of Three Gorges Reservoir Area and the theoretical calculation formula to determine the navigable hydraulic parameter of 3000-ton ships． The results of research contribute to the channel rectification project， the navigation period of the Reservoir Area and the Three Gorges shipping returns． References | Related Articles | Metrics

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Optimum Design Model Test of the Inlet-Middle Pier Forms for Zhongzuipo Hydropower Spillway Liu Teng,Yang Sheng-fa,Li Li-qiang,Xie Long 2012, 31(4): 881-884.  DOI: 10.3969/j.issn.1674-0696.2012.04.35 Abstract ( )   PDF (226KB) ( )   To improve the flow forms and the discharge capacity of the diversion canal for the spillways of the Zhongzuipo hydropower project，experiments are arranged to optimize the design of the middle pier of in-flow of the canal． A changed width oblique tail submerged pier optimum design is proposed; the flow pattern and discharge capacity of this design is verified to achieve satisfactory result． References | Related Articles | Metrics

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Research on Security-Risk Assessment System of Coastal Caisson Wharf Construction Wang Xue-jun,Zhang Zhi-min 2012, 31(4): 885-889.  DOI: 10.3969/j.issn.1674-0696.2012.04.36 Abstract ( )   PDF (186KB) ( )   Caisson wharf is commonly used in China’s coastal ports as well as in the construction of deep-water berths． Due to the increasingly serious engieering safety problem in port construction，an assessment index systerm is proposed and an evaluation model is established to guide security-risk assessment of caisson wharf construction． References | Related Articles | Metrics

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Study on Liner Operators’Controlling of Empty Containers’In-Transit Inventory Song Ruo-chen,Zhao Yi-fei 2012, 31(4): 890-894.  DOI: 10.3969/j.issn.1674-0696.2012.04.37 Abstract ( )   PDF (201KB) ( )   To solve the issue of container management，based on rational analysis concerning the cost composition of empty containers’in-transit inventory，an optimization model which aims to minimize the overall cost of empty containers’in-transit inventory is devised． Besides，a specific case is also taken into consideration，so as to provide the best distribution program for liner operators as well as verify the feasibility and efficiency of this model． References | Related Articles | Metrics

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Analysis on Reliability of Logistic Service Supply Chain Based on Markov Process Li Yang-zhen,,Zhang Xi-zheng 2012, 31(4): 895-899.  DOI: 10.3969/j.issn.1674-0696.2012.04.38 Abstract ( )   PDF (221KB) ( )   The relationship between logistic capacity and demand is analyzed; structure of two-echelon logistics service supply chain is established． Reliability model based on Markov process is proposed; stable probability of each state is obtained by solving state transition equation． The conclusion is drawn that the structure of LSSC can influence service reliability; the reliability of series-parallel connection is prior to series connection; changes of failure rates or maintenance rates of nodecompany will affect the reliability of the system． References | Related Articles | Metrics

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Free Bending of Ship Plate of Different Thickness on High-Frequency Induction Zhang Ji-xiang,An Guo-yin,Li Zheng-jun,Wang Zhi-xiang 2012, 31(4): 900-904.  DOI: 10.3969/j.issn.1674-0696.2012.04.39 Abstract ( )   PDF (438KB) ( )   In this paper，a FEM model of high-frequency induction free bending is established; the heated temperature， stress，deformation，residual stress and bending angle after cooling，etc are studied on different thickness ship plate． The results show that the steel plate can be heated to 860℃ above the austenitic temperature． Bending angle of ship plates of different thickness in one-sided is 10-2 degree in the case of the absence of constraints and ignoring ship plate weight． The stresses are to the yield stress and promote plastic deformation of different thickness after the high-frequency heating． When the plate is cooled，the residual stress will mainly be concentrated at the bottom of the coil． Heating temperature is gradually decreased with some fluctuations in the slab area． The maximum bending angle first increases and then decreases; the maximum stress first decreases and then increases as the thickness increases． Under the conditions of a given frequency and power， the best result of deformation thickness of plate is 14mm in high-frequency induction heating． References | Related Articles | Metrics

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Study on Fleets’Building Strategy for Large-Scale Iron and Steel Enterprises Zhang Lei,Hu Hao,Jia Da-shan 2012, 31(4): 905-909.  DOI: 10.3969/j.issn.1674-0696.2012.04.40 Abstract ( )   PDF (193KB) ( )   The necessity for iron and steel enterprises to build their own fleet is discussed with the consideration of the current condition of iron ore shipping market． Two modes of building shipper-owned-fleet are then proposed; the integer programming method is used to determine the scale of the fleet． The appropriate scale of the fleet will fulfill the transport demand at a low cost，extend profit margins of the company and strengthen iron and steel enterprises’control over the whole industry chain． A fleet planning example from 2011 to 2015 of an iron and steel enterprise is used to illustrate the established method． The preliminary results show that the method is effective． References | Related Articles | Metrics

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A Blind Symbol Timing Offset Estimation Scheme for OFDM Systems Xu Wei-yang 2012, 31(4): 910-913.  DOI: 10.3969/j.issn.1674-0696.2012.04.41 Abstract ( )   PDF (216KB) ( )   In the light of limitation of relying on constant modulus constellation in the existing method，a blind symbol timing synchronization technique applicable for arbitrary constellations is proposed． Through maximizing the non-Gaussianity of the signal in the receiver end，this scheme could lock the start point of the DFT window into the safe region，thus the synchronization is obtained． With the exploitation of sliding window，the estimation accuracy can be further improved． The simulation result proves the efficiency of the proposed method． References | Related Articles | Metrics

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Design and Implementation of Teaching Evaluation System Based on B/S Huang Kun,Wang Jia-wei,Luo Xian,Wang Ren-hong 2012, 31(4): 914-917.  DOI: 10.3969/j.issn.1674-0696.2012.04.42 Abstract ( )   PDF (609KB) ( )   A universal framework for implementing the undergraduate teaching evaluation system based on the B/S three-tier structure mode is introduced． Firstly，the system of evaluation is introduced in brief，and then the practical realization methods of the stored procedure in the statistical analysis module are particularly introduced． Furthermore，the implementing process of exporting data to excel is implemented，which is based on C# and WebDataWindowControl of DataWindow． NET． By using this framework，the collected and simulative data is treated and statistically analyzed with the evaluation system． In addition，all data also confirm to those got by hand，which validates the feasibility of framework． References | Related Articles | Metrics