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15 February 2015, Volume 34 Issue 1 Previous Issue    Next Issue

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Static, Dynamic and Fatigue Life Analysis of Straddle Type Joint Turnouts Beam Wang Zhixiang, Zhu Ming, Zhang Jixiang 2015, 34(1): 1-5.  DOI: 10.3969/j.issn.1674-0696.2015.01.01 Abstract ( )   PDF (1389KB) ( )   The static, modal and fatigue life analysis of the third segment of joint five-switch beam has been studied by the ANSYS Workbench. The analysis displayed that the maximum equivalent stress under static loads is 52.44MPa, less than the yield limit strength of the material. Maximum deformation is about 0.29mm in the upper beam. There is obvious stress concentration point occurred in the welding position. Frequency of the first modal is about 51Hz. The simulation result of switch beam’s fatigue life is 49.6 years. The results of analysis show that the static strength of the switch beam meets requirements. The deformation position of the first three modes in modal analysis coincides with the static strength deformation. The rigidity of this position needs to be strengthened. The fatigue life of switch beam satisfies the requirement of 25 years life of steel structure. References | Related Articles | Metrics

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Deflection Characteristics of Three-Pylon Suspension Bridge Based on Gravity Stiffness Method Wang Libin, Wu Yong, Jin Bohan 2015, 34(1): 6-11.  DOI: 10.3969/j.issn.1674-0696.2015.01.02 Abstract ( )   PDF (946KB) ( )   The dimensionless deflection expressions of main cable for three-pylon-four-span suspension bridges under concentrated load and distributed load were derived by gravity stiffness method. Then the influence rule of the number of spans, the ratio of side span to main span, dead load and live load intensity on the gravity stiffness deflection of three-pylon-four-span suspension bridge was analyzed respectively. And the new characteristics of three-pylon-four-span suspension bridge which were distinguished from the conventional three-pylon-four-span suspension bridge were also analyzed. These conclusion indicates that the mechanical characteristics of the multi-span main cable under dead and live load determine the basic characteristics of structure stiffness of three-pylon-four-span suspension bridges; the different behavior between one-span cable and multi-span cable causes the difference of mechanical characteristics between two-pylon suspension bridges and three-pylon suspension bridges; and the behavior characteristics of three-pylon suspension bridges based on the gravity stiffness deflection method keeps well consistent with the behavior characteristics based on finite elements method on overall structure. References | Related Articles | Metrics

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Analysis on Vessel Collision with Bridges Based on Nonlinear Finite Element and Study on Impact Force Gao Rongxiong 2015, 34(1): 12-15.  DOI: 10.3969/j.issn.1674-0696.2015.01.03 Abstract ( )   PDF (1724KB) ( )   Vessel collision with bridges, which is a complicated transient dynamic process, usually causes a great risk. The crashing action was applied on bridge structures in the form of equivalent static force in current specifications to calculate the impacting force. The impacting force and damage effect of collision was analyzed on the basis that an inland river bridge in construction was subjected to vessel collision, including geometric and material nonlinearity. The numerical analytical results at different initial velocity and the relation between equivalent static force and crashing velocity with different standards were investigated comparatively, and the impacting force of vessel collision with bridges was discussed. Further, the equivalent impacting force of vessel collision with bridges in inland rivers was also explored. The referential formula of impacting force for bridge design was recommended in the current specifications. References | Related Articles | Metrics

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Fatigue Life Evaluation of U-Rib Butt Weld of the Orthotropic Steel Bridge Ji Bohai, Zhu Wei, Fu Zhongqiu, Chen Xiongfei, Xu Hui 2015, 34(1): 16-21.  DOI: 10.3969/j.issn.1674-0696.2015.01.04 Abstract ( )   PDF (967KB) ( )   The fatigue life of U-rib butt weld of orthotropic steel bridge deck of Jiangyin Yangtze River Highway Bridge was researched, which was based on real-time monitoring of dynamic strain of U-rib butt weld on the Jiangyin Yangtze River Highway Bridge, with the consideration of the rain-flow counting method and BS5400 specification. The stress variation of U-rib butt weld with the load of moving vehicle was obtained by using the fatigue-loaded vehicle model and the traffic flow simulation. The fatigue damage degree was calculated, and the calculation results were compared with the measured ones in detail. The measured results show that the maximum stress amplitude of the slow traffic lane and the fast traffic lane both exceed the fatigue limit of U-rib, which is 70 and 110 MPa respectively, which may cause failure with the accumulation of the fatigue damage. The FEM result shows that although large stress amplitude is produced when the vehicle passes through the bridge, the damage accumulation is mainly in low cycle. The fatigue life of the U-rib which locates on the slow lane is lower than that of the designed bridge life. So it is important to pay attention to the U-ribs of the slow lane. References | Related Articles | Metrics

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Effects of Angular Displacement of Skewback on Stability Performance of Circular Arch Deng Yisan, Xu Bin, Wang Yannan 2015, 34(1): 22-24.  DOI: 10.3969/j.issn.1674-0696.2015.01.05 Abstract ( )   PDF (505KB) ( )   According to the energy criterion of structure stability, the balance equation and the equilibrium stability equation were obtained. Next, the effects of angular displacement of skewback on buckling performance of circular arch were worked out by means of the simultaneous solution of balance equation and equilibrium stability equation. The following conclusions can be drawn from the above research: the angular displacement of skewback will lead to the decrease of buckling load of deep arch; the effects of angular displacement of skewback on buckling load are changed by opening angle of arch; the effects of angular displacement of skewback on buckling load are more evident with the decrease of slenderness ratio of arch; the dividing values of geometric parameter of arch are enlarged with the increase of angular displacement of skewback. References | Related Articles | Metrics

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Influencing Factors of Main Cable Wires Corrosion Rate of Suspension Bridge Chen Xiaoyu, Tang Maolin, Shen Ruili 2015, 34(1): 25-29.  DOI: 10.3969/j.issn.1674-0696.2015.01.06 Abstract ( )   PDF (1126KB) ( )   The factors which influenced the cable steel wires corrosion was classified into two main kinds,that is,external enviroment factors and the own state of steel wires.And other influence factors,such as humidity,temperature,atmospheric pollutants,wire tension,initial loss and the main cable bendine were elaborated in detail.Based on the obtained research results,the influence mechanism of above factors on the cable steel wires corrosion and the corrosion rate was analyzed in detail.And then the main factors influencing the cable steel wires corrosion were obtained.Therefore,the multi-wrre-group corrosion test corrosion test considering the interaction between various factors was proposed,which was more appropriate to simulate the actual main cable corrosion process. References | Related Articles | Metrics

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Reinforcement Boundary of Steel in the Reinforcing Layer of RC Beam under the Secondary Load Zhou Jianting, Li Zhigang, Liu Simeng 2015, 34(1): 30-33.  DOI: 10.3969/j.issn.1674-0696.2015.01.07 Abstract ( )   PDF (667KB) ( )   The ultimate failure of RC beams was analyzed with increasing section method at different initial load to study the effects of secondary load on the relatively height of ultimate compressive region and the maximum strengthening quantity, the calculation formulas of RC strengthened beam’s relatively height of ultimate compressive region and maximum strengthening quantity of steel in the reinforcing layer at different initial load were obtained when the beams strength occurred plastic failure. The Finite Element Analysis (FEA) software ABAQUS was used to do the calculation verification, and the calculation results agreed well with analysis ones. References | Related Articles | Metrics

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Deformation Law Analysis and Safety State Evaluation of Embankment on Broken Line Subgrade Wang Teng, Chen Liang, Zhu Hongzhou, Miao Cunque 2015, 34(1): 34-39.  DOI: 10.3969/j.issn.1674-0696.2015.01.08 Abstract ( )   PDF (1307KB) ( )   In order to study the deformation law of embankment on the broken line subgrade and find the monitoring sensitive point, and then evaluate its safety state based on deformation law, PLAXIS was used to simulate the deformation law of embankment on the broken line subgrade in the filling period, the normal operation period, and the case of rainfall infiltration. Results showed that the monitoring sensitive points of the filling period were mainly distributed in slope crest of each filling layer. In the operation period they were located in the tension fracture area of top and shear outlet of landslide of toe, which was likely due to an arc sliding result from the soil mechanics parameters attenuation. However, monitoring sensitive points would be distributed in the upper part of embankment in rainwater infiltration region when raining. That was because embankment slides locally would be occurred with the increase of rainfall depth. Finally, this paper identified the risk level of the embankment based on the size of the displacement in the process of deformation development of the embankment. References | Related Articles | Metrics

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Experimental Study on the Influence of the Admixture for the Double Grout Guo Qiwu,Yin Xiaobo,Chen Yuanjiang,Wan Xiufeng 2015, 34(1): 40-43.  DOI: 10.3969/j.issn.1674-0696.2015.01.09 Abstract ( )   PDF (644KB) ( )   Contrast tests were carried out on the base of chemical reaction mechanism analysis on the cement-sodium silicate slurry, to research the influence of two different kinds of admixtures including Aluminum chloride solution and Disodium hydrogen phosphate on the solidification characteristics of slurry. The gelation time test, stone rate test, compressive strength test and durability test were included. Therefore, the influence law of the two admixtures on the solidification characteristics of cement-sodium silicate slurry was obtained preliminarily. References | Related Articles | Metrics

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Comparison for Two Methods of Measurement of Foamed Asphalt Viscosity Xu Dawei, Zhang Shuai 2015, 34(1): 44-47.  DOI: 10.3969/j.issn.1674-0696.2015.01.10 Abstract ( )   PDF (648KB) ( )   Brookfield viscometer and improvement of Brookfield viscometer were used to measure foamed asphalt, and 70# conventional asphalt and SBS modified asphalt were selected to produce foamed asphalt. Compared with two kinds of foamed asphalt viscosity measurement method, the results are as follows: asphalt bubbles influencing shear stress should be taken into consideration. Bubbles of 70# conventional asphalt influences viscosity a lot, and improvement of rotation viscosity is less than 70# conventional asphalt, but rotation viscosity is larger than 70# conventional asphalt. Because of larger viscosity of SBS modified asphalt, inerratic bubbles of asphalt have little effect on measurement of viscosity. Improvement of rotation viscosity and rotation viscosity are less than that of SBS modified asphalt. In order to measure the viscosity of foamed asphalt more accurately, it is suggested that the caliber of sample tube should be increased to avoid the influence of asphalt bulbbles on the shear stress. References | Related Articles | Metrics

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Influence of Processing and Storage Temperature on SBS Modified Asphalt Performance Han Sen , Niu Dongyu, Chen Kai, Gao Jingwei, Li Jun 2015, 34(1): 48-53.  DOI: 10.3969/j.issn.1674-0696.2015.01.11 Abstract ( )   PDF (788KB) ( )   Four kinds of the processing temperatures (160,170,180,190 ℃) and three kinds of the storage temperatures（90, 120,150 ℃）, which were in different range, were selected to process and store the different SBS modified asphalt (E+S-YS, E+S-YY, S+S-YY). The temperature sensitivity, high temperature performance and low temperature performance were analyzed by asphalt experimentation and repeat creep test. The results show that the different processing and storage temperatures affect the performances of three kinds of SBS modified asphalt differently. When the processing temperature is 180 ℃ and the storage temperature is 150 ℃, the various performances of S-YY modified asphalt achieve the optimal effect; while the processing temperature is 170 ℃ and the storage temperature is 120 ℃, the various performances of S-YS modified asphalt achieve the optimal effect. The recommended value of the processing and storage temperature for enhancing the performance of different SBS modified asphalt was proposed. References | Related Articles | Metrics

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Water Damage Mechanism of Epoxy-Asphalt Concrete Zhou Wei , Zhao Hui, Wen Jun , Cai Fangchang , Jiang Tao 2015, 34(1): 54-59.  DOI: 10.3969/j.issn.1674-0696.2015.01.12 Abstract ( )   PDF (1276KB) ( )   Combining with the photomicrographs of epoxy-asphalt concrete and fluorescence photomicrographs of the section of epoxy-asphalt concrete, the mechanical strength, water absorption, pH value and DMA analysis of epoxy-asphalt was used before and after freeze-thaw cycles, to investigate the damage mechanism of mechanical properties of epoxy asphalt under freeze-thaw cycles. The results show that: the causes of the damage of epoxy-asphalt concrete under freeze-thaw cycles were that the dispersion of epoxy-asphalt-aggregates was destroyed in the physical aspects and the curing structural of epoxy were bracken in the chemistry aspects. At the initial stage of freeze-thaw cycles, the water molecules into the epoxy asphalt system cause epoxy hydrolyzed, which destroys the molecular structure of the cross-linked epoxy resin curing; at the late stage of freeze-thaw cycles, asphalt gradually separates out of the curing system, which causes the curing system structure damaged, the tensile strength of the system reduced by about 32.42 % from 5.12 MPa to 3.51 MPa, and the adhesive strength reduced by 3.25 % from 47.87 MPa to 46.31 MPa. References | Related Articles | Metrics

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Water Stability of Warm Recycled Asphalt Mixture Cheng Peifeng, Han Yongqiang 2015, 34(1): 60-63.  DOI: 10.3969/j.issn.1674-0696.2015.01.13 Abstract ( )   PDF (714KB) ( )   Using freeze-thaw splitting test method, research the water stability change rule of warm recycled asphalt mixture with different RAP（reclaimed asphalt pavement materials）content, short-term aging of warm recycled asphalt mixture and different molding temperature. Study results show that: the water stability of warm recycled asphalt mixture waken with the increase of RAP content, getting stronger after short-term aging. In order to ensure the road performance, molding temperature of warm recycled asphalt mixture can reduce 25 ℃~30 ℃ at most when RAP content is within 40%, 10 ℃ when the content is 50%. References | Related Articles | Metrics

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Application Research on Technology of Scrap Tire Rubber Asphalt Regenerating Old Asphalt Pavement u Chunying,, Yu Mingming,, Liu Kaiqiong 2015, 34(1): 64-67.  DOI: 10.3969/j.issn.1674-0696.2015.01.14 Abstract ( )   PDF (776KB) ( )   Based on large and medium-made project S305 line in Guizhou province, the technology of scrap tire rubber asphalt regenerating old asphalt pavement was researched. The method to determine “rubber asphalt & regenerated asphalt" miscible proportion was put forward. The performance of asphalt rubber regeneration binder, the mix design method and its road performance were verified. The results show that when the proportion of the rubber asphalt is not less than 70%, all the indexes of asphalt rubber regeneration binder meet the technical standards of asphalt rubber; the road performance of asphalt rubber regeneration mixes AC13 reaches the effect of modified asphalt mixture, and with an excellent comprehensive performance. References | Related Articles | Metrics

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Shear Strength of Gravel Soil Landslide in the Three Gorges Reservoir Zone Guo Xifeng , Yan Echuan, Liu Yang 2015, 34(1): 68-71.  DOI: 10.3969/j.issn.1674-0696.2015.01.15 Abstract ( )   PDF (859KB) ( )   According to the in-situ shear test for three typical landslides in Fengjie County, the shear strength of gravel soil before and after immersion in water was analyzed, and its relationship with the grain distribution was also analyzed. The shear strength parameters of gravel soil were obtained and its relationship with the gravel content and water content was also obtained. The analysis provides experimental basis and mechanical parameters for the analysis of similar landslide treatment and stability, which guides the design and construction. References | Related Articles | Metrics

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Study on One-Dimensional Mathematical Model of Slope Erosion Li Wenjie, Wang Jie, Zhang Shuaishuai 2015, 34(1): 72-77.  DOI: 10.3969/j.issn.1674-0696.2015.01.16 Abstract ( )   PDF (1195KB) ( )   A one dimensional model of slope erosion and sediment yield was established by combining the hydrological module and soil erosion and sediment yield module, according to the dynamical mechanism of hydrological and soil erosion processes. The processes of interception, evapotranspiration, infiltration, groundwater and overland flow were simulated in the hydrology module, and the sediment module simulated the raindrop splash detachment, overland flow erosion and sediment transport processes. The whole model was verified by the measured data of runoff plot and sediment. The simulation results indicate that the hydrological module is relatively precise and the soil erosion and sediment yield module simulates the sediment yield reasonably, so the overall effect is better. References | Related Articles | Metrics

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Field Tests on Horizontal Ultimate Bearing Capacity of Small Diameter Steel Pipe Rowed Piles Xiang Bo , Zhuang Weilin, He Yunyong, Zhou Lirong 2015, 34(1): 78-83.  DOI: 10.3969/j.issn.1674-0696.2015.01.17 Abstract ( )   PDF (918KB) ( )   According to the preloading destructive test on small diameter steel pipe rowed piles, with a landslide worksite as the pile load test area, the horizontal load-displacement curve of different combinations of the structures was obtained. During the preloading test, when the load was increased to a limited value, the infection point of deformation curve appeared; when the load reached the ultimate value, large deformation of pile tops and partial outflow of the soil between piles appeared. However, the whole collapse or buckling failure of the steel pipe pile did not occur. According to the slow loading method, the ultimate horizontal bearing capacity of two rows of piles and three rows of piles was determined with different pile spacing and row spacing. The conclusions are drown by the tests that a composite bearing system is built through interaction of the steel pipe piles and soil between piles, and it greatly increases the bearing capacity of the small diameter steel pipe piles compared with the system without considering the action of soil between piles. Such factors as the bent structure strength, rows of steel pipe piles and reasonable row spacing affect its bearing capacity. References | Related Articles | Metrics

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Impact of Guardrail Height Variation on Anti-collision Capability Cui Hongjun, Cui Shan, Xing Xiaogao, Liang Guofeng 2015, 34(1): 84-86.  DOI: 10.3969/j.issn.1674-0696.2015.01.18 Abstract ( )   PDF (720KB) ( )   Because of pavement overlaying, the guardrail height lowered, which influenced the safety performance of guardrail significantly. LS-DYNA, a kind of finite element (FE) analysis software, was used to carry out the simulated collision test with different heights of waved guardrails. The relationship between guardrail height lowering and security capabilities was analyzed quantitatively. The height threshold value of guardrail crash performance which met the requirement of specifications was determined. Reforming project on the original guardrail of highway along the sea was proposed, and the reforming project was proved to meet the requirement of specifications by computer simulation. References | Related Articles | Metrics

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Assessment Method for Roadside Risk Grade of Freeway in Mountainous Areas Liu Yan , Chen Jianlei , Liu Zhigang, Zou Fei, Hu Shijing 2015, 34(1): 87-90.  DOI: 10.3969/j.issn.1674-0696.2015.01.19 Abstract ( )   PDF (614KB) ( )   Firstly, it was stated that the research on safety assessment for roadside accident of freeway in mountainous areas was significant for reducing traffic accidents. Roadside risk indicators were introduced as intermediate variables to indirectly show the relation between the roadside accident risk and the condition of road, traffic as well as the environment. In addition, based on the subordinate function in fuzzy mathematics, the method to quantitatively assess the roadside accident risk grade of freeway in mountainous areas was established. Finally, the reasonableness and effectiveness of the proposed method was verified through the application on four freeways in mountainous areas in Guizhou province. References | Related Articles | Metrics

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Statistical Relationship Between Death Population of Road Traffic Accidents and Sunspot Activity Feng Wen, Li Kejun 2015, 34(1): 91-94.  DOI: 10.3969/j.issn.1674-0696.2015.01.20 Abstract ( )   PDF (831KB) ( )   The relationship between death population of road traffic accidents and solar activity was investigated through ensemble empirical mode decomposition analysis, cross-correlation analysis, cross-wavelet analysis, and etc., which was based on the information of yearly mean sunspot number and annual death population (DP) of road traffic accident events in China from 1951 to 2009. The results obtained show that DP is statistically positively correlated with the 11-year-cycle solar activity. DP is not only closely related with human activities, but also affected by solar activity indeed. References | Related Articles | Metrics

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Research of Vehicle Conversion Coefficients on Urban Expressway Ramp at Merging Area Xue Xingjian 2015, 34(1): 95-99.  DOI: 10.3969/j.issn.1674-0696.2015.01.21 Abstract ( )   PDF (867KB) ( )   The passenger-car equivalents theory and methodology of urban expressway merging area afflux car was discussed. Based on measured data of Shanghai expressway and from the analysis of process of ramp vehicles merging mainline, considering varies influencing factors about vehicles merging mainline, such as length of car bodies, vehicle performance and time headway distribution of vehicles of outer lane in mainline of various models, afflux car passenger-car equivalents models were established and the suggested values of afflux car PCE in two afflux modes were provided, according to ramp merging capacity of various models of vehicles, sufficiently accelerated afflux mode and parking afflux mode. The conclusion indicates that afflux car PCE have much to do with afflux modes of ramp vehicles and vehicles volume of outer lane in mainline, PCE and the main line outside lane traffic is correlated; at the same rate of outside lane, the PCE of sufficiently accelerated afflux mode is less than parking afflux mode. In calculating, the ramp merge area capacity should not simply take a certain value of PCE to afflux car References | Related Articles | Metrics

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Pedestrian Swarming Classification Method Based on Forward Searching and K-Means Clustering Algorithm at Signalized Intersection Yu Quan, Wang Meng, Deng Xiaohui 2015, 34(1): 100-104.  DOI: 10.3969/j.issn.1674-0696.2015.01.22 Abstract ( )   PDF (782KB) ( )   Pedestrian groups at signalized intersection were the researched object, the achievements of living things were used for reference, and the conception of pedestrian swarming was given. At the same time the conception of pedestrian swarming circus was defined. Also a method based on forward searching was provided. K- means clustering algorithm was used to analyze 737 pedestrian swarming samplings of 60 hours video data at the signalized intersection, and the values of feature parameters of different pedestrian swarming were obtained. The research result shows that pedestrian swarming circus can evaluate the level of service of pedestrian crossing at signalized intersection in China, and can make good foundation for control algorithm and model of pedestrian crossing. References | Related Articles | Metrics

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Comprehensive Evaluation Study on Seismic Adaptability of Mountainous City Road Network Song Yongchao，Yang Yongqian 2015, 34(1): 105-109.  DOI: 10.3969/j.issn.1674-0696.2015.01.23 Abstract ( )   PDF (639KB) ( )   In order to research the earthquake environmental adaptability of mountainous city road network, and analyze the characteristics and earthquake damage environment, the mountainous city earthquake adaptability evaluation index system was established based on the principle and methods of selecting evaluation. The weight of each factor was determined by using Analytic Hierarchy Process. The seismic adaptability comprehensive evaluation model of urban road network of mountainous city was constructed using the fuzzy comprehensive evaluation. A local area road network seismic adaptability of Chongqing was evaluated. References | Related Articles | Metrics

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Vulnerability Analysis of Urban Road Network Based on Complex Network Theory Huang Darong , Shen Libing, Zhao Ling 2015, 34(1): 110-115.  DOI: 10.3969/j.issn.1674-0696.2015.01.24 Abstract ( )   PDF (1373KB) ( )   Firstly, the statistic characteristics of complex network were introduced, and Xinxiang urban road network was taken as a case study, which calculated the statistical characteristics of complex network, including degree, betweenness, clustering coefficient and etc. Then, according to the topology characteristics of city road network, the model of road network vulnerability research was established by the statistic features of complex network theory. Taking the road network in Xinxiang city as an example, the vulnerability of the road network of Xinxiang city in two attack strategies which were randomly attacked and maximum degree attack were demonstrated. Finally, the vulnerability of every node in the network was calculated when they were attacked by assaulting the network rodes one by one, and the key sections of road network were found out by this algorithm. It is of important and practical significance for the network protection which takes the maintenance as the main body in post traffic times. References | Related Articles | Metrics

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Chaotic Characteristics and Application of Traffic Noise of Urban Road Zhang Wenhui, Luo Wenwen, Li Zhuo, Xu Huizhi 2015, 34(1): 116-120.  DOI: 10.3969/j.issn.1674-0696.2015.01.25 Abstract ( )   PDF (744KB) ( )   Traffic noise was composed of time series, which was collected at certain section in urban road. Autocorrelation function was used to calculate the delay time. When the autocorrelation coefficient attenuated to 0.4, the delay time to reconstruct phase space was 12. The training set included two groups of noise samples was employed to calculate the correlation dimension. When embedding dimension was 6, the correlation dimension kept invariant. Therefore, the embedding dimension of system was 3 and traffic noise samples were of chaotic characteristics. Based on the reconstructed phase space, state points and near points, the fitting parameters were calculated. The two groups of traffic noise samples were predicted respectively by chaotic models and then compared the results with those got by the training set. The results show that chaotic models are suitable to predict the traffic noise of urban road in a short time. The average relative errors of two groups of noise samples were 8.56% and 9.33% individually. References | Related Articles | Metrics

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Congestion Charging Effect Considering State-Financed Travel Wang Yu 2015, 34(1): 121-126.  DOI: 10.3969/j.issn.1674-0696.2015.01.26 Abstract ( )   PDF (831KB) ( )   According to the differences of state-financed travel and non-state-financed travel, the impact of state-financed travel on congestion charging was analyzed, and the measures on the internalization of external costs on state-financed travel were put forward. Furthermore, the congestion charging models before and after the internalization were set up.Through comparing the examples, it is concluded that the congestion charging effect after the internalization is always better than before with the optimal charge strategy, considering the total network cost, social welfare, the total amount of travel, and the sharing of the public transportation. The difference before and after internalization decreases with the increase of time value parameters and increases with the boost of the proportion of stated-financed travel; and it increases with the increase of sensitivity parameters of elastic demand. It is indicated that the measures of the internalization of external costs on state-financed travel can better improve the effect of congestion charging with smaller time value, greater proportion of stated-financed travel, and greater sensitivity parameters of elastic demand. References | Related Articles | Metrics

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Quantitative Study of Site Construction Labor Demand for Building Engineering in Chongqing Zhao Bin, Lin Shitong 2015, 34(1): 127-130.  DOI: 10.3969/j.issn.1674-0696.2015.01.27 Abstract ( )   PDF (508KB) ( )   The problems of site construction labor demand for building engineering in Chongqing were put forward and discussed to optimize the allocation of skilled workers, facilitate human resources planning and budgeting, improve systemization and standardization of construction management, enhance the capability in overall management and construction and ensure the engineering quality and safety. The trades of skilled workers in site construction and essential factors which influenced the allocation of skilled workers were determined, and the project category was classified. On the basis of field research, questionnaires and experts interview, the labor demand forecasting model for the allocation of skilled workers in building engineering at project level was developed, with the site construction experience into consideration. Finally, the model was tested and validated through five completed building engineering projects. It is concluded that the model can serve as a practical and advanced tool for predicting the labor demand for the skilled workers. References | Related Articles | Metrics

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Noise Control of Offshore Platform Based on Statistical Energy Method Jiao Ziquan, Sun Yonggan, Liu Wenjing 2015, 34(1): 131-134.  DOI: 10.3969/j.issn.1674-0696.2015.01.28 Abstract ( )   PDF (628KB) ( )   The acoustic vibration VA ONE software was applied to establish statistical energy analysis model in order to analyze the cabin noise prediction and study the noise value of living compartments. According to the principle of noise control, three types of noise reduction measures had been made for the typical cabin, including the noise source, transmission and accepted cabin. By comparing the noise reduction measures, draw two kinds of measures are that the main souree of noise is isolated and reducing noise for cabin. description of these two measures would not only be significant noise reduction effect, but in the actual construction process has a strong feasibility and economy advantages. References | Related Articles | Metrics

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Optimization of the Power Train Mount System of Electric Vehicle Li Yaoyao, Wang Hui 2015, 34(1): 135-139.  DOI: 10.3969/j.issn.1674-0696.2015.01.29 Abstract ( )   PDF (874KB) ( )   The power train mount system of electric vehicle with six degrees of freedom mathematical model and ADAMS simulation model were established. By analyzing the mode and vibration response of the mount system, the characteristics of mount system vibration was researched. Firstly, that the dynamic reaction force at the supporting of power train mount reached the minimum value was chosen as the optimal objective; secondly, the axial static stiffness of each mount was chosen as design variables; thirdly, the reasonable distribution of power train inherent frequency, mount and power train displacement were chosen as constraint conditions; finally, the optimization on mount parameters were conducted with ADAMS/Insight. The results show that the driver’s average sound pressure level at ear point is significantly reduced by 13%, and it was even reduced by 21% on the higher sound pressure level. The optimization well achieves the purpose of the noise reduction of vibration isolation. References | Related Articles | Metrics

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3-D Simulation Analysis on Backfire Conditions of HCNG Engine with High Compression Ratio He Yituan, Zhou Lei, Yuan Junyong, Shao Yiming, Deng Biao 2015, 34(1): 140-143.  DOI: 10.3969/j.issn.1674-0696.2015.01.30 Abstract ( )   PDF (992KB) ( )   In order to research the backfire mechanism of one HCNG engine with high compression ratio, an experiment of backfire conditions was carried out. On the basis of the engine specifications and experimental data, a 3-D model of HCNG engine was established by AVL-Fire software, which made the simulation calculation of backfire conditions. The test and simulation results show that, the engine is easier to backfire at the condition of higher compression ratios; if other conditions keep unchanged, backfire is likely to happen when the ignition advanced angle is closer to top dead center (TDC); large valve overlap and high compression ratio cause the waste gas with high temperature back flow to the intake ports, which is one of the causes of backfire; the invalid ignition close to the TDC of exhaust stroke increases the gas temperature near the intake valve, which raises the backfire trend. References | Related Articles | Metrics

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Calculation Method of Eddy Current Conversion Coefficients of Eddy Current Retarder Hu Donghai, He Ren, Tang Bao 2015, 34(1): 144-148.  DOI: 10.3969/j.issn.1674-0696.2015.01.31 Abstract ( )   PDF (936KB) ( )   The impact of eddy current conversion coefficient on theoretical calculation of eddy current retarder braking torque was analyzed. Through the analysis of experimental data of braking torque of two different eddy current retarders, differential equation of eddy current conversion coefficient was established. The initial conditions of differential equation were obtained by direct search toolbox of MATLAB, and then the numerical solution of eddy current conversion coefficient was gained by Runge-Kutta method. The braking torque of an eddy current brake was calculated by the derived calculation method. The calculation data accords with the experimental data, and it is indicated that the proposed calculation method is available and can solve the difficult problems of eddy current retarder in modified optimization and new product design. References | Related Articles | Metrics

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Experimental Study on Tire Pressure’s Influence on Steering Tie Rod Han Jiapeng, Zhang Ruijing, Zhang Yaxin, Tan Derong 2015, 34(1): 149-151.  DOI: 10.3969/j.issn.1674-0696.2015.01.32 Abstract ( )   PDF (478KB) ( )   The test principle and method of the tire pressure influencing on the tie rod force was introduced; the real vehicle road test was designed, and the relationship among tire pressure, vehicle speed and steering tie rod force was obtained. The test results show that with the same tire pressure, the impact of the vehicle speed on steering tie rod is relatively small; with the same vehicle speed, the tie rod force changes obviously with the reduce of the tire pressure. References | Related Articles | Metrics

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Main Structure of 400 t Deck Erection Gantry of Walking Type Xue Zhiwu, Li Bazhou, Dang Yanfeng 2015, 34(1): 152-156.  DOI: 10.3969/j.issn.1674-0696.2015.01.33 Abstract ( )   PDF (1400KB) ( )   ANSYS shell 63 unit and beam188 unit were applied to establishing the finite element model of the whole crane, to simulating the static loading test of crane and determining the accuracy of the model and the stress state of the overall structure. The model modal analysis and harmonic response analysis of the crane was carried out in order to obtain the inherent frequency characteristics, which provided the theoretic basis for later improvement and optimization. At last, the dynamic response of the structure in the lifting and swing shift process was further researched, which ensured the safety of structure. References | Related Articles | Metrics

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Recovery Characteristics and Energy Flow of Electric Vehicle Regenerative Braking System Analysis Zhang Shupei, Huang Xuan, Jing Zhecheng 2015, 34(1): 157-161.  DOI: 10.3969/j.issn.1674-0696.2015.01.34 Abstract ( )   PDF (1018KB) ( )   Electric vehicle and hybrid electric vehicle equipped with regenerative braking system can recycle the energy originally consumed by the braking system to reduce energy consumption and improve the vehicle’s economy. Through analyzing the energy flow relationship of regenerative braking system braking and referring to the existing evaluation methods, a set of evaluation index which can targetedly and comprehensively response regenerative braking system recovery characteristics was put forward. Taking a electric car for example, through experiments the relationship of recovery characteristics and the regenerative braking energy flow was made clear, and the reference for the research and development of the regenerative braking system was provided. References | Related Articles | Metrics

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Study on Tolerances Analysis of Body-in-White and Optimize the System Li Jun, Liu Zhao, Hong Yintao, Mao Xiaowen 2015, 34(1): 162-166.  DOI: 10.3969/j.issn.1674-0696.2015.01.35 Abstract ( )   PDF (1010KB) ( )   A system that could assign and analyze the tolerance of sheet-metal automatically in the design period was proposed. The proposed system used non-cooperative game to optimize tolerance allocation and used Monte-Carlo method to detect whether the gap and flush was appropriate or not. Furthermore, the super slip was predicted. According to the different super slips, different improved plans of product and procedure were provided. Finally, production rule and relationship data base were used to enlarge the optimization data base. The proposed system can save the time of designing cycle and costs, and improve the level of tolerance management and quality. References | Related Articles | Metrics