Archive

15 August 2011, Volume 30 Issue 4 Previous Issue    Next Issue

---

For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Select

Calculation of Main Cable Zero-stress Length for Fuling Qingcaobei Yangtze River Bridge HU Na，ZHANG Yong-shui，CHENG Ning-bo 2011, 30(4): 709-711.  DOI: 10.3969/j.issn.1674-0696.2011.04.001 Abstract ( )   PDF (339KB) ( )   Calculation of zero-stress length of main cable is the effective guarantee for construction control of suspension bridge superstructure. Common software Midas /Civil was used to build finite element model for Fuling Qingcaobei Yangtze River Bridge to correct zero-stress length of cable strand for suspension bridge. The general methods of adopting common software to build model of suspension bridge and of calculating the zero-stress length of main cable were put forward to provide reference for this kind of calculation. References | Related Articles | Metrics

Select

Influence on Long-span Continuous Rigid Framed Bridge of Site Effect Based on Power Spectrum Method XIONG Huan，ZHANG Ben，WEI Lu-yao，WANG Zi-jian 2011, 30(4): 712-716.  DOI: 10.3969/j.issn.1674-0696.2011.04.002 Abstract ( )   PDF (472KB) ( )   A computing model of the entire bridge was established based on a prestressed concrete continuous rigid framed bridge，which was 346m. The bridge was to be excited under six working conditions respectively using the power spectrum generated from standard response spectrum. By compared multi-support excitation with uniform excitation，this essay analyses the influence of site effect on continuous rigid framed bridge. The research result indicates that for continuous rigid framed bridge of high piers and long span，site effect is mainly disadvantageous to the mid-span cross-section of girders， and can cause a abrupt change of internal force of the bottom of piers. References | Related Articles | Metrics

Select

Closed Solutions of Composite Steel-Concrete Beams Displacement Considering Shear Lag Effect CHEN Mian 2011, 30(4): 717-720.  DOI: 10.3969/j.issn.1674-0696.2011.04.003 Abstract ( )   PDF (195KB) ( )   In view of the primary beam theory，which assumes that the stress of reinforced composite steel-concrete beams was well-distributed along the width． But considering the shear lag effect，the stress of concrete slab and upper and lower beam alar plates were distributed approximately as a parabola． In order to estimate the stress condition of the reinforced composite steel － concrete beams precisely，different shear lag warping displacement functions were separately given to the concrete slab and beam alar plate． Meanwhile，the potential variational theory was adopted to derive the differential equation of reinforced composite steel-concrete beams considering shear lag effect，and obtain its closed form solution． Through the results comparison of example analysis and ANSYS analysis，it reveals that: the relative error of results by this method and ANSYS is only 4． 0%，thus the veracity and precision of this method are verified． References | Related Articles | Metrics

Select

Finite Element Models of Main Girder in Cable-stayed Bridge Stability Analysis HUANG Zhi-hua，DENG Ping-yue，ZHANG Da-wei，ZHANG Peng 2011, 30(4): 721-724.  DOI: 10.3969/j.issn.1674-0696.2011.04.004 Abstract ( )   PDF (241KB) ( )   The stability of a prestressed concrete cable-stayed bridge was analyzed with FEM while the construction of the longest double cantilever finished． The girder of this bridge was double main rib． Different kinds of finite element model of the girder were selected in the eigenvalue buckling analysis． According to the results，the characteristics of these finite element models in simulation of the girder rigidity are discussed． The disadvantages of the traditional single-girder and doublegirder models are pointed out． The method of using equivalent rigidity to simulate the lateral connection of double-girder model is also proposed． It is convenient． References | Related Articles | Metrics

Select

Finite Element Analysis of Stone Arch Bridge Considering Spandrel Construction Combined Action LI Zheng，XIANG Zhong-fu，LI Zi-qiang，PAN Zheng-hua 2011, 30(4): 725-728.  DOI: 10.3969/j.issn.1674-0696.2011.04.005 Abstract ( )   PDF (343KB) ( )   In order to make the result closer to the actual stress，spandrel construction combined action was considered when the finite element model of stone arch bridge was established． On this basis，transverse tie bar method and equipollent arch method were offered to improve calculation model． Then the feasibility and effectiveness of the methods could be demonstrated in project cases． The conclusions could provide guidance for bearing capacity estimation and reinforcement of stone arch bridge． References | Related Articles | Metrics

Select

Stress Analysis of Fatigue Details of Deck of Orthotropic Bridges in High-Speed Railway TIAN Yang，LI Yun-sheng，ZHANG Yan-ling，DAI Yun-liang 2011, 30(4): 729-733.  DOI: 10.3969/j.issn.1674-0696.2011.04.006 Abstract ( )   PDF (732KB) ( )   Finite-element model was established by ANSYS for orthotropic steel bridge deck． Taking the standard ZK live load of PDL as the train load，the local stresses of the joint of rib and deck，the rib and crossbeam，and the cut-outs of the crossbeam were analyzed respectively． Analysis results showed that the stress of bridge deck mainly centered on intersecting part of the U-shaped rib，crossbeam，and bridge deck． Along the edge of the U-shaped rib there was obvious stress concentration． In the whole bridge deck，the local stress level of the cut-outs in crossbeam was almost the highest; the maximum stress at crossbeam cut-outs was mainly concentrated at the lower circular of the cut-outs，which was one of the positions prone to fatigue damage． References | Related Articles | Metrics

Select

Stress Analysis of Suspender Anchor Structure of Steel Box Arch LV Cheng-lin，AN Yong-ri，ZHENG Gang 2011, 30(4): 734-739.  DOI: 10.3969/j.issn.1674-0696.2011.04.007 Abstract ( )   PDF (849KB) ( )   Binzhou Road NO． 1 bridge in Jiangjin of Chongqing was taken as the research object． Four suspender anchor structure models of different tectonic forms were established and calculated by using large common software ANSYS． The analysis results show that the changes of the angle of the suspender and arch ribs centerline would affect limit ultimate bearing capacity and stiffness variation slightly while the connection form of pipe and arch ribs bottom would affect them largely． References | Related Articles | Metrics

Select

Study on Characteristics of Circumferential Motion of Cylinder Pile Cluster DENG Shao-yun， 2011, 30(4): 740-742.  DOI: 10.3969/j.issn.1674-0696.2011.04.008 Abstract ( )   PDF (232KB) ( )   By flume test on the effect degree of different cylinder pile cluster on the flow regime of uniform water flow，and contrastive analyzing the several series of experimental data，we have found the scientific law of cylinder pile cluster effect on the flow regime of uniform water flow，the nature and extent disparity of different cylinder pile cluster effect on the same uniform water flow，the scientific law of affected scope of the different cylinder pile cluster of the flow regime of uniform water flow，the scientific law of the flow resistivity，the density of cylinder pile lines and the length of cylinder pile cluster effect on the water flow and the scientific law of the effect of different uniform water flow with various velocity respond to cylinder pile cluster． Moreover，we concluded that the drag of cylinder pile cluster was one but not the only one factor which influenoed the water flow． The arranging formats and up-flow angles of cylinder pile cluster had different degree of effects on the flow regime of water flow． And the eflects of these two factors were larger than that of the drag． References | Related Articles | Metrics

Select

Widening Mountainous Highway with Half-bridge and Slope Base Composite Embankment Structures ZHOU Zhi-xiang，ZHENG Wen，YOU Tao 2011, 30(4): 743-746.  DOI: 10.3969/j.issn.1674-0696.2011.04.009 Abstract ( )   PDF (344KB) ( )   As the high standard of keeping mountainous highway smooth，a new method which is called“Widening the mountainous highway with half-bridge and slope base composite embankment structures”was put forward． This method aims at strengthening the original embankment with the reinforced concrete frame． On this basis，the highway could be broadened with cantilever construction． The biggest advantage of this method does not only eliminate high fill and deep cut but also keep a clear traffic in the process of construction． References | Related Articles | Metrics

Select

Key Technology Research on Stone Arch Bridge Strengthened by Composite Main Arch Circle Method ZHOU Lei，ZHOU Jian-ting，HUANG Can，ZHANG Li-wen，SUN Yi-sheng 2011, 30(4): 747-750.  DOI: 10.3969/j.issn.1674-0696.2011.04.010 Abstract ( )   PDF (419KB) ( )   A finite element analysis relying on actual project was conducted in view of the phenomenon that，the arch reinforcement of composite section bearing capacity calculated by converting section area and moment of inertia cannot reflect to the stress state of each part． The results shows the maximum compressive stress of original arch section have reduced after reinforcement，while the new reinforced layer is under the negative state of tensile stress． It illustrates the mechanical characteristics of the reinforcement technique． References | Related Articles | Metrics

Select

Support Mechanics Analysis of Enlarging Tunnel with Large Cross-section at Initial Construction Stage JIN Xue-hui，CHENG Chong-guo 2011, 30(4): 751-754.  DOI: 10.3969/j.issn.1674-0696.2011.04.011 Abstract ( )   PDF (562KB) ( )   The value of surface settlement and the value of the flexion and bolt axial force at the initial stage of tunnel lining were worked out by using the ANSYS FEM software to simulate the construction of the onsite expansion of Yuzhou Tunnel in Chongqing． The affected region of subsidence in expansion construction of shallow tunnels was worked out after comparing and analyzing the results of numerical simulation and the monitoring values． The result reflects that the redistribution of rock internal force has comparatively large effect at the initial construction stage of flexion and the bolt axial force in extension regi References | Related Articles | Metrics

Select

Influence of Asphalt Semi-rigid Base Modules on Pavement Structural Stress ZHANG Rui-zhuo，LING Tian-qing，YUAN Ming，NING Hua-yu 2011, 30(4): 755-758.  DOI: 10.3969/j.issn.1674-0696.2011.04.012 Abstract ( )   PDF (418KB) ( )   For different modulus of asphalt semi-rigid base，these factors，such as the vertical stress on surface，the tensile stress on the bottom layers of surface and base，the deflection on surface and surface shearing stress，were analyzed to find out the location of each maximum value of them，and the change trend with various semi-rigid modulus． The results show that too large modulus of asphalt semi-rigid base will lead to pavement rut，shear failure，base course crack and reduction of fatigue life of surface． But too little modulus will be lack of strength． By overall analysis，the modulus of asphalt semi-rigid base shall be selected from 1000 ～ 1600MPa． References | Related Articles | Metrics

Select

Impact of High Viscosity Modifier on Asphalt Properties CONG Zhuo-hong，WU Xi-rong，ZHENG Nan-xiang，LU Ming-hua 2011, 30(4): 759-762.  DOI: 10.3969/j.issn.1674-0696.2011.04.013 Abstract ( )   PDF (350KB) ( )   High viscosity asphalt properties of different asphalt grade and different kind mixed with TPS were analyzed． With the TPS dosage increasing，the asphalt properties are tending to be stable． The recommended high viscosity asphalt recipes are the base asphalt mixed with 12% dosage TPS，and the SBS I-D mixed with 8% dosage TPS． References | Related Articles | Metrics

Select

Indoor Molding Technology and Road Properties of Coarse Rubber Granule Asphalt Mixture WANG Xiu-yun，YU miao，WU Guo-xiong 2011, 30(4): 763-767.  DOI: 10.3969/j.issn.1674-0696.2011.04.014 Abstract ( )   PDF (288KB) ( )   Raw material and gradation were studied in order to search for a more reasonable molding process of coarse rubber asphalt mixture． By an orthogonal experiment，a combined method of vibration compaction and large Marshall second compaction were used to study how rubber dosage，vibration frequency and vibration time，compaction temperature and compaction times influenced on the compaction degree． Voidage was taken as the main guidepost to evaluate the compacting effect of the mixture． A more reasonable molding process for the coarse rubber asphalt mixture is put forward． The high-temperature behavior of the mixture with different rubber voidage was evaluated for recommending the reasonable rubber content． References | Related Articles | Metrics

Select

Performance of Cement and Fly Ash Base Course Binder with Chemical Activator LI Yi，WANG Lian-jun，CHEN Ming-zhe，LI Pei-jun 2011, 30(4): 768-772.  DOI: 10.3969/j.issn.1674-0696.2011.04.015 Abstract ( )   PDF (621KB) ( )   When the proportion of cement and fly is 1: 2，the external addition method and dosage of N-type activator and Utype expansion agent were studied by taking account of different indexes，such as unconfined compressive strength，cleavage strength，flexural tensile strength and flexural tensile modulus． The Structure and morphology of cement and fly ash binder were observed by means of SEM to analyze the hydration mechanism of the binder． The results show that N-type activator could significantly increase fly ash activity and U-type activator could improve crack resistance of mixture． The cement and fly ash stabilized base course binder with 2% N-type activator and 3% U-type activator have good mechanical properties and crack resistance． References | Related Articles | Metrics

Select

Study on Working Performance of Adhesives for CFRP LING Cai-zhu，NING Jin-cheng ，PENG Bo 2011, 30(4): 773-777.  DOI: 10.3969/j.issn.1674-0696.2011.04.016 Abstract ( )   PDF (428KB) ( )   The rheological behaviors of three different thixotropic agents in epoxy adhesives system were studied． These agents are hydrophilic silicon dioxide gas，hydrophobic silicon dioxide gas and organic bentonite． The results show that these three thixotropic agents could thicken the density of impregnated resin． The influences of storage time，coupling agent and curing agent on the thickening effects are distinct． References | Related Articles | Metrics

Select

Application of Reliability Analysis in Grey Cluster Slope YANG Xiao，LI Peng，XIAO Sheng-xie 2011, 30(4): 778-781.  DOI: 10.3969/j.issn.1674-0696.2011.04.017 Abstract ( )   PDF (221KB) ( )   The process rainfall and the greatest magnitude were selected as the essential decisive factors of reliability analysis． The reliabilities of these two factors were introduced to the traditional BP neural network to forecast the grey cluster problems of slope． Two typical samples of the five typical slope，were analyzed while the other three were selected as prediction samples． By analysis，the reliability of slope when the two decisive factors acted on the slope separately and the accurate forecast results which are subjected to the nine selected factors can be provided as references for the slope engineering． References | Related Articles | Metrics

Select

Actual Measurement and Numerical Analysis of Instability Destruction of Fill Embankments on Slope Foundations in K28 Section in Meihe Highway XIANG Chong ，FEI Wei-shui ，ZHANG Yu-fang ，WEI Shao-wei 2011, 30(4): 782-785.  DOI: 10.3969/j.issn.1674-0696.2011.04.018 Abstract ( )   PDF (691KB) ( )   Numerical analysis and actual measurement were performed to study the failure mode and process of the fill embankments on slope foundations taken K28 + 360 ～ + 860 section in Guandong Meihe highway as the study object． Based on the analysis，the following conclusions were obtained: the destroy pattern of the sliding surface of fill embankments on slope foundations of K28 + 360 ～ + 860 section was the slop embankment sliding caused by the interface soften of the original surface of the slope and fill embankment． The constructions of the highway blocked the groundwater discharge and reduced the strength of the original surface of the slope，which was the main reason of the slide of the fill embankments on slope foundations． References | Related Articles | Metrics

Select

EPS Cushion of Forepoling Pile and Its Optimization by Numerical Simulation SUN Hong-li，LIU Yuan-xue，YE Si-qiao，RAN Shi-ping 2011, 30(4): 786-789.  DOI: 10.3969/j.issn.1674-0696.2011.04.019 Abstract ( )   PDF (555KB) ( )   Aiming at reducing the loads on forepoling piles and optimizing its design，a polystyrene foam ( EPS) cushion was proposed to set up behind the forepoling pile． The sensitivity analysis was implemented under the conditions of different cushion thickness，different types of EPS by numerical simulation． The research results show that: After setting EPS cushion， the soil pressure，maximum moment and maximum shear force on forepoling pile and pile top displacement are significantly reduced． And in the range 0 － 0． 8m cushion，the thicker the cushion is，the more significant the reduction is． For example，the earth pressure on forepoling pile decreases by 20% to 45%． For different types of EPS materials，the load effect on pile decreases with EPS material density decreasing． References | Related Articles | Metrics

Select

Application of Wave Detection Technology in Compaction Quality Inspection for Stone-filled Embankment Used Large Sized Particles LI Xia，ZHU Gen-qiao 2011, 30(4): 790-793.  DOI: 10.3969/j.issn.1674-0696.2011.04.020 Abstract ( )   PDF (519KB) ( )   The wave signals of the rock-filled embankment were gathered by RSM － 24FD，and then the wave velocity of every testing point was analyzed based on cross-spectral analysis theory． And the dry density and porosity of the points were gained by the method of digging holes and filling water． The fitted formulas between the wave velocity and the dry density and porosity were established，and the results indicate there are well correspondences between the wave velocity and the dry density and porosity， References | Related Articles | Metrics

Select

Analysis of Earth Pressure on Oil Pipe ZHOU Zheng-feng，LING Jian-ming，LIANG Bin 2011, 30(4): 794-797.  DOI: 10.3969/j.issn.1674-0696.2011.04.021 Abstract ( )   PDF (320KB) ( )   Based on ABAQUS，normal and shear actions between contact surfaces of oil pipe and its surrounding soil were simulated by Coulomb friction model，and finite element model was established to analyze the structural response of pipe and soil． The earth pressure distribution，value and pipe-soil relative stiffness were obtained by finite element analysis． The results indicate that the interaction between pipe and soil has a significant effect on earth pressure distribution and value． The earth pressure distribution along the horizontal and vertical direction appears to be parabola curve within the pipe diameter． And changes appear abruptly at the interfaces of pipe subgrade and backfill soil with different stiffness． The vertical earth pressure coefficient obtained by FEM is less than those calculated by Marston theory etc． ，while horizontal earth pressure coefficient obtained by FEM is greater than those calculated by Marston theory etc． ． Furthermore，the pipe-soil relative stiffness is much greater than that calculated by present theory method，and interaction between pipe and soil should be considered in mechanical behavior analysis of oil pipe． References | Related Articles | Metrics

Select

Safety Mechanism Analysis of Bucket Foundation Penetration in Silts QI Jian-feng，LEI Ting，LI Yuan，LI An-long 2011, 30(4): 798-802.  DOI: 10.3969/j.issn.1674-0696.2011.04.022 Abstract ( )   PDF (509KB) ( )   Based on the model tests and FEM，a comprehensive analysis of the hydraulic gradient and soil slug in the process of suction penetration of bucket foundation in the silts was carried out to deeply study the suction penetration mechanism． The results indicate that the seepages inside and outside of the bucket foundation are the direct reasons for the formation of soil slugs． The seepage changes not only the permeability of the soil body but also the physical and mechanical properties， and enhances the rheological property and time effect，and there are high hydraulic gradient and the safety mechanism preventing soil flow failure for the silts in the bucket foundation． Thus，the soil slug failure is not seepage failure，or unloading expansion yet，but is a complex deformation failure mode under the protection of safety mechanism of bucket foundation． References | Related Articles | Metrics

Select

EPS Cushion of Forepoling Pile and Its Optimization by Numerical Simulation SUN Hong-li，LIU Yuan-xue，YE Si-qiao，RAN Shi-ping 2011, 30(4): 803-806.  DOI: 10.3969/j.issn.1674-0696.2011.04.023 Abstract ( )   PDF (310KB) ( )   Aiming at reducing the loads on forepoling piles and optimizing its design，a polystyrene foam ( EPS) cushion was proposed to set up behind the forepoling pile． The sensitivity analysis was implemented under the conditions of different cushion thickness，different types of EPS by numerical simulation． The research results show that: After setting EPS cushion， the soil pressure，maximum moment and maximum shear force on forepoling pile and pile top displacement are significantly reduced． And in the range 0 － 0． 8m cushion，the thicker the cushion is，the more significant the reduction is． For example，the earth pressure on forepoling pile decreases by 20% to 45%． For different types of EPS materials，the load effect on pile decreases with EPS material density decreasing． References | Related Articles | Metrics

Select

Trafic Flow Prediction Based on Wavelet Analysis and Nonparametric Regression DOU Hui-1i，WU Zhi-zhou 2011, 30(4): 807-811.  DOI: 10.3969/j.issn.1674-0696.2011.04.024 Abstract ( )   PDF (366KB) ( )   According to the complexity of the field traffic system and the uncertainty of the traffic flow，a traffic flow predic- tion model which combined an algorithm of wavelet analysis with nonparametric regression was established based on the thoughts of pattern recognition．First，theory of wavelet analysis was applied to eliminate the effect of noise Oil the real-time traffic data，which can reflect the essenee of traffic flow．Then with the worked traffic data，K-nearest neighbor nonparamet- tic regression was used to predict traffic flows of the next time period．Finally，according to the proposed algorithm，the prediction analysis was carried out．The results indicate that the model has a finer precision and can be used for the real- time dynamic traffic flow prediction． References | Related Articles | Metrics

Select

Estimation on Non-motor Vehicle Parking Lot Scale at Suburban Stations of Shanghai Metro Line 9 CHEN Ying-xue，WU Bing，LIU Zhi-gang，LI Lin-bo 2011, 30(4): 812-817.  DOI: 10.3969/j.issn.1674-0696.2011.04.025 Abstract ( )   PDF (858KB) ( )   A survey was made on non-motor vehicle parking lot scale of line TX in Tokyo． The influence factors like station passenger flow，distance between station，land development around station，distance from city-center were analyzed and a fuzzy logic model was built among the four influence factors and parking lot scale． At last，reasonable non-motor vehicle parking lot scale of suburban station of Shanghai Metro Line 9 was estimated based on the fuzzy logic model and the survey data of influence factors of Metro Line 9． References | Related Articles | Metrics

Select

Optimization for BRT Ticket Price under Condition of Low-carbon Traffic JIANG Jin-liang，SONG Rui，LIU Jie 2011, 30(4): 818-822.  DOI: 10.3969/j.issn.1674-0696.2011.04.026 Abstract ( )   PDF (169KB) ( )   According to the special requirements of public transport，the system of low-carbon traffic was put forward． Firstly the content of low-carbon traffic was introduced; secondly the cooperative and competitive game between normal bus and BRT was analyzed，and described mathematically by Logit model; then the ticket price was used as a decision variable to establish BRT ticket price optimization model based on maximizing the benefit value of low-carbon traffic; finally a case was given to verify the model below，and the result demonstrated the model’s feasibility． References | Related Articles | Metrics

Select

Optimum Selecting Method in Determination Object of Expressway Maintenance Budget Quota CONG Zhuo-hong，WU Zheng-ying，ZHENG Nan-xiang，LI Xiao-dong 2011, 30(4): 823-827.  DOI: 10.3969/j.issn.1674-0696.2011.04.027 Abstract ( )   PDF (177KB) ( )   Fuzzy comprehensive evaluation method was adopted based on analytic hierarchy in selecting the determination object of expressway maintenance quota． The principle and application of fuzzy comprehensive evaluation method based on analytic hierarchy were introduced and a simulate calculation on the real situation of some construction teams was made，in which the selected result satisfied the average advanced principle of quota preparation． The results show that it is reasonable and feasible to use fuzzy comprehensive evaluation method based on analytic hierarchy as the optimization in the object determination of expressway maintenance quota． References | Related Articles | Metrics

Select

Flood Risk Assessment of Highway Network in Wanzhou，Chongqing ZHONG Ming-yin，TANG Hong-mei，CHEN Hong-kai 2011, 30(4): 828-832.  DOI: 10.3969/j.issn.1674-0696.2011.04.028 Abstract ( )   PDF (421KB) ( )   In Wanzhou area of Chongqing，the town was taken as the administrative unit． With the consideration of the geological hazards，hazards inducing environment，highway type，highway network technical grade and highway network density indexes，the zoning map of highway network flood risk in Wanzhou area of Chongqing based on GIS software and AHP integration method was obtained． Combining with the comprehensive evaluation indexes，the highway network flood risk grade was divided into two grades，namely moderate risk and high risk． The proportions of these two risk level areas were 68． 55 percent and 31． 45 percent separately． References | Related Articles | Metrics

Select

Calculation of Dynamics Parameters of Sanyanyu Gully in Zhouqu，Gansu DENG Hu，CHEN Ning-sheng，HU Gui-sheng，LU Yang， 2011, 30(4): 833-838.  DOI: 10.3969/j.issn.1674-0696.2011.04.029 Abstract ( )   PDF (770KB) ( )   By the site investigation of the debris flow disaster Sanyanyu gully，the first － hand data of the disaster was obtained． The mud － rock flow velocity，flow，impact of Sanyanyu gully ( Dayu gully and Xiaoyu gully) were analyzed and calculated based on these collected data． The calculation results show that mud － rock flow velocity and flow reach the scale of super debris flow，and the impact is much greater than protection engineering design of the gully． At last，the specific suggestions on disaster prevention are given based on these studies． References | Related Articles | Metrics

Select

Hydraulic Model Test of Liujiagou Hydropower Plant YAN Xue-li，YANG Sheng-fa，SUN Lian-chao 2011, 30(4): 839-842.  DOI: 10.3969/j.issn.1674-0696.2011.04.030 Abstract ( )   PDF (415KB) ( )   For solving the problem of discharge flow regime，by the means of optimizing test of hydraulic model of Liujiagou hydropower station，two arcs and straight segment structure form of the right spillway guide wall were used． For achieving satisfactory effect of energy dissipation，the joint energy dissipation structure，which included T pier on discharge groove export platform and through shore-slope dispersing flow and crashing shot out flux via platform，was adopted． References | Related Articles | Metrics

Select

Concentration and Pollution Character of Heavy Metals in Sediments from Meijiang River in Xiushan Manganese Mine Area ZENG Qing，YANG Qing-wei，LIU Xue-lian，LI Jin-fu，XU Yuan 2011, 30(4): 843-847.  DOI: 10.3969/j.issn.1674-0696.2011.04.031 Abstract ( )   PDF (345KB) ( )   Two evaluation methods，including the Pollution Load Index ( IPx ) and the Potential Ecological Risk ( RI ) ，were adopted to analyze surface and profile distributions and pollution character of heavy metals ( Mn、Pb、Cu、Zn、Cr and Cd) in sediments in Xiushan section of Meijiang river． The results show that the concentrations of these six metals in the surface sediments decrease in order of Mn ＞ ＞ Zn ＞ Pb ＞ Cu ＞ Cr ＞ Cd． Only the contents of two metal elements，Zn and Cu，decrease along with increasing depth，while other metals display no regularity． The values of IPx ( 2． 7) and RI ( ＞ 600) indicate this region was heavily contaminated by these six heavy metals，and there are serious ecological risks for local organism． Key words References | Related Articles | Metrics

Select

Simulation for External Flow Field around Automobiles Based on Models of Different Parametric Shape DU Zi-xue，ZHANG Jie 2011, 30(4): 848-851.  DOI: 10.3969/j.issn.1674-0696.2011.04.032 Abstract ( )   PDF (492KB) ( )   The CAD model of a certain type automobile was created with three － dimensional modeling software． Based on knowledge engineering module，a set of aerodynamic parameters of vehicles was set up ． These parameters were angle of front windscreens ( FWW) ，angle of rear windscreens ( BWW) ， approach angle( AFA) ，departure angle( DRA) ． Eight different car models were obtained by changing these parameters． Then parametric model will be analyzed for aerodynamic by using of computational fluid dynamics ( CFD) software，Star － ccm + ． Under different parametric models，the drag coefficient and lift coefficient could be simulated． Moreover，analysis of affection for aerodynamic performance could also be carried on． References | Related Articles | Metrics

Select

Design and Simulation of Assist Characteristic Curve of Electro-hydraulic Power Assist Steering System ZHU Pei，ZHANG Zhen-yu 2011, 30(4): 852-855.  DOI: 10.3969/j.issn.1674-0696.2011.04.033 Abstract ( )   PDF (473KB) ( )   The assist characteristic curve of EHPS was analyzed and the function of the curve was given． For designing the assist characteristic curve of EHPS，the relationship of the steering assist power， torque on steering wheel and steering resistance torque from ground was analyzed，and the model of steering resistance torque from ground was built． By building all parts of models of EHPS，motor rotating speed was deduced and the 3 － D assist characteristic curve map of motor speed， steering wheel angular velocity and vehicle speed was plotted． For applying the assist characteristic curve to practice，BP neural network was used to optimize the assist characteristic curve，and then the assist characteristic curve under any vehicle speed was obtained． Simulation of the EHPS verified this assist characteristic curve having a good performance． References | Related Articles | Metrics

Select

Testing Method of Engine Matching Based on New Test System QU Da-yong，YANG Xin-gang，WU Yu-chen，LIANG Cheng-qi 2011, 30(4): 856-859.  DOI: 10.3969/j.issn.1674-0696.2011.04.034 Abstract ( )   PDF (280KB) ( )   Based on the characteristics of the new test equipment that measurement of multi-module synchronization，trigger start and so on，the influence of the performance of air filter，intercooler，silencer，and radiator on engine performance in economic and power was analyzed． Some useful methods of matching test to the vehicle on road were summarized． And then the application of the new testing equipment in matching test with some examples was introduced． References | Related Articles | Metrics

Select

Sliding Mode Control of Permanent Magnet Synchronous Motor Position Servo System HUANG Fei 2011, 30(4): 860-863.  DOI: 10.3969/j.issn.1674-0696.2011.04.035 Abstract ( )   PDF (304KB) ( )   A sliding mode control ( SMC) approach，which is based on exponential reaching law，was introduced． PI controller of velocity loop was introduced to reduce system steady-state error and to increase system response speed，the sliding mode controller of positional loop was applied to restrain effects of parameter uncertainties and external disturbance． The simulation results show that the controller is of good response speed and able to track the given position quickly and accurately． References | Related Articles | Metrics

Select

Half Shaft ＆ Full Floating Power Reserved Drive Axle for Micro-automobile WU Xian-you，LIU Ren 2011, 30(4): 864-867.  DOI: 10.3969/j.issn.1674-0696.2011.04.036 Abstract ( )   PDF (247KB) ( )   Home-made micro automobile is equipped with the transmission including three forward gears and1 reverse gear． A“power-reserved transmission”，which had two forward gears and one direct gear，was added to the differential drive axle． Therefore，the micro automobile can have six forward gears to enlarge output torque of driving wheels and widen the range of speed，thus the vehicle performance and fuel economy could be improved． References | Related Articles | Metrics

Select

Comparison of Passenger Vehicle Fuel Consumption Standards in USA，EU and Japan YAO Yong，DI Min-yan 2011, 30(4): 868-872.  DOI: 10.3969/j.issn.1674-0696.2011.04.037 Abstract ( )   PDF (441KB) ( )   As the warming of world climate，the governments around the world have been controlling strictly to emissions of greenhouse effect gases． They have made some rules to passenger vehicles． As these countries and areas using different controlling targets and measuring methods to decrease the emission of greenhouse effect gases，these targets were compared after changing them of America and Japan into one same condition of NEDC． The results show that among the rules around the world， those of EU and Japan are the strictest，and that of U． S． is lenient which encourages the development of diesel vehicles． References | Related Articles | Metrics

Select

Dynamics Analysis of Fuel Tax Impacting on Chinese Logistics Industry LI Yu-min 2011, 30(4): 873-879.  DOI: 10.3969/j.issn.1674-0696.2011.04.038 Abstract ( )   PDF (354KB) ( )   The system dynamics method was used to establish a causal relationship model of fuel tax impacting on logistics industry． A cause and effect cycle analysis of logistics cost，industry profits was made． Industry revenues，fuel cost，logistics cost of 20 investigated enterprises were sampled to establish a dynamic model of fuel cost per month of single vehicle in a typical logistics enterprise． A sensitivity analysis of fuel tax levies，fuel saving technology coefficient and energy altering coefficient impacting on fuel costs was made． The results show that: logistics cost keeps increasing since the implementation of fuel tax two years ago，while the profits of the whole industry decrease． With fuel prices keeping rising，the profit margin of whole may continue decreasing． Combining with system dynamics analysis，some countermeasures and suggestions are given for adjusting fuel tax from three aspects: logistics enterprises，logistics industry，and the government． References | Related Articles | Metrics

Select

Fatigue Crack Behavior of Welded Structure of Duplex Stainless Steel 2205 WANG Zhi-xiang，ZHANG Xin，ZHANG Ji-xiang 2011, 30(4): 880-884.  DOI: 10.3969/j.issn.1674-0696.2011.04.039 Abstract ( )   PDF (487KB) ( )   Take standard SE( B) as a sample，the fatigue crack growth behavior of weld metal ( WM) ，heat affected zone ( HAZ) and base metal( BM) of Duplex Stainless Steel 2205 were tested on PLG-200 fatigue testing machine under different stress ratios． Through regression analysis of experimental data，the regression equation and the curve of the propagation rate da /dN and the stress intensity factor ΔK were obtained． The results show that the fatigue crack growth rate of WM is the slowest and the ability to resist fatigue crack growth is the highest in the three parts while BM is just the opposite． Secondly， as for the sensitivity to the stress change，WM is the highest，then HAZ，and BM is the lowest． References | Related Articles | Metrics

Select

Study on Reasons and Identification of False Waste Products in Machining CHEN Si-yi 2011, 30(4): 885-888.  DOI: 10.3969/j.issn.1674-0696.2011.040 Abstract ( )   PDF (205KB) ( )   Combined with machining，falsely-wasted products were defined from the discordance of measuring and design base，location and design base． Main reasons were studied． Process size conversion using Extremum Method and compensation law among the errors of composition rings were helpful when technology base discord with design base． Based upon the theory of Process Dimension Chain，the distribution areas of qualified products，false waste products and waste products were determined，and identification methods for false waste products were raised． References | Related Articles | Metrics