LI Jie , FENG Decheng , REN Xiaodan , WAN Zengyong
2017, 45(08):1099-1107. DOI: 10.11908/j.issn.0253-374x.2017.08.001
Abstract:The stochastic damage model for concrete is introduced in the paper. The fundamental parameters of the model are calibrated through the concrete constitutive model in the Chinese design code. In order to make the model convenient for engineering applications, some modifications are made to account for the complicated interaction effects between reinforcement steels and concrete in realistic structures. Then the model is implemented into the structural analysis software ABAQUS and OpenSees through user subroutines, and used to simulate different kinds of structural member experiments. The results indicate that the proposed model can reflect the mechanical behaviors of concrete and reinforced concrete members and structures, and it offers an effective way for nonlinear analysis of structures in engineering.
2017, 45(08):1108-1113. DOI: 10.11908/j.issn.0253-374x.2017.08.002
Abstract:Firstly, balance equation of composite beam element with interlayer slips under corotational coordinate system was deduced. Combining initial strain method,equivalent nodal force formulation of shrinkage and creep was obtained. Based on the corotational method, using the transformation matrices relating local and global quantities, a practical algorithm for analysis of composite beam with interlayer slips considering geometric nonlinearity, concrete shrinkage and creep synchronously was put forward. The advantage of this approach is that it leads to the separation of geometrical and material nonlinearities such as shrinkage and creep. The shrinkage and creep is only present at the level of the local element, whereas the geometrical nonlinearity is included in the transformation matrices. Finally, it was illustrated that the geometric nonlinearity is coupled with shrinkage and creep for composite beam with interlayer slip by an example.
YI Jiang , LIU Chuang , LI Jianzhong
2017, 45(08):1114-1122. DOI: 10.11908/j.issn.0253-374x.2017.08.003
Abstract:Based on a real singletower cablestayed bridge, both velocity pulses and real earthquake waves are used to study the influence of ground motion frequency characteristics on seismic behavior of singletower cablestayed bridges. The analysis results show that long duration velocity pulse contained by nearfault ground motions have significant effects on the seismic response of singletower cablestayed bridges. Especially, when the ratio of peak ground velocity (Vp) to peak ground acceleration (ap) is large, the period of velocity pulses gets close to the period of 1st vertical bending mode of the bridge, and thus the response of the tower, girder, cables and bearings increases significantly with possibility that cable relaxation and end span uplift might occur. The results show that cable relaxation and end span uplift have a significant influence on the response of the structure like deck displacement, cable axial force and bearing vertical reactions. The response of the deck displacement and cable axial force would possibly be underestimated if neglecting influence of cable relaxation and end span uplift.
YANG Chunyu , WANG Tongyue , CHEN Ting , MA Juntao
2017, 45(08):1123-1130. DOI: 10.11908/j.issn.0253-374x.2017.08.004
Abstract:Using the data of sunshine duration over Chinese 34 main cities from 1988 to 2012, the authors studied the changes in annual and seasonal trends of the sunshine duration by liner trend analysis and accumulative anomalies, from the angle of light climate division. It is found that the annual sunshine duration distributes obviously at different levels and reduces from the 2nd to the 5th light climate zone, except the 1st light climate zone. The characteristics of seasonal sunshine duration are similar with that in the whole year, but the increasing or decreasing amplitude is different between 5 light climate zones. This research provides a new theoretical method to understand the changes of light climate in our country and there will be of great significance to guide the architectural lighting design and energy conservation in corresponding areas.
ZHAO Hongduo , ZHU Xingyi , TU Huizhao , YANG Zhen
2017, 45(08):1131-1135. DOI: 10.11908/j.issn.0253-374x.2017.08.005
Abstract:The concept and framework of smart pavement are interpreted and proposed in this paper. The vision of transportation system is clarified as “zero casualties, zero delay, zero maintenance, zero emission and zero fail”. Towards the vision, the definition of smart pavement is given based on the elements of smart organism. Smart pavement is defined as an infrastructure that composed of advanced structure and material, monitoring network, data center, communication network and energy supply system, which has the ability of selfmonitoring, automatic analyzing, selfadaptation, information interacting and continue energy supplying. Based on the definition, the function characteristics including basic performance, smart ability, information service, sustainability are proposed. Then a 5 levels system is developed for the smart ability of smart pavement. This paper constructs the framework of Smart pavement from five aspects: physical elements, information direction, energy way, spatial location and P2X (pavement to X) service. The concept and framework can be used as the guide for smart pavement research and application.
WU Jiaorong , YU Miao , Zhu Qizheng
2017, 45(08):1136-1142. DOI: 10.11908/j.issn.0253-374x.2017.08.006
Abstract:Based on the commute survey data of 15 residential districts, this paper determined a reasonable budget value of single commute travel time was 30 minutes. Then 30minute accessible commute range of respectively using car, railway and bus based on secondarydeveloped electronic map API(application programming interface) and geographic information system(GIS) technology was depicted. From the traffic system configuration in 30minute accessible commute range, the reason for the difference of accessible commute range was analyzed. Correlation among density of various facilities providing working post, the proportion of respondent workplace and the ratio of using car for commute in 30minute accessible commute range was specially analyzed. Finally, traffic improvement strategy of classified residential districts was proposed.
2017, 45(08):1143-1149. DOI: 10.11908/j.issn.0253-374x.2017.08.007
Abstract:The purpose of this study is to quantitatively analyze the impact of ride comfort and the vibration state of the vehicle during the operation of the bus.The smartphone as a data collection terminal, The multidimensional variables characterizing ride comfort are constructed by statistical analysis of velocity and latitude and longitude data, and obtains the smooth comfort index by the principal component analysis; on the other hand, applied Fourier transform with acceleration data to build vibration comfort index. This paper makes up for past researchs that ignored the running state on the impact of riding comfort. Using smartphonebased acquisition data to constructed comfort measurement indexs is operational. Applied Logit regression model with cruising data and Results indicated that the comfort indexes can objectivity reflect the passenger subjective perception of bus running status.
YU Zhuoping , LI Yishan , XIONG Lu
2017, 45(08):1150-1159. DOI: 10.11908/j.issn.0253-374x.2017.08.008
Abstract:The motion planning problem of unmanned autonomous vehicle (UAV) is reviewed. UAV operates in both structured road and unstructured field with differential constraints. The problem of trajectory generation can be simplified with the differential flatness of Ackerman steering vehicle. Compared to direct trajectory generation method, pathvelocity decomposition method is more popular. Clothoids, splines and polynomial spirals are used for path generation. The two major planning algorithms of great practical significance are rapidly random tree(RRT) in the name of samplingbased and A* in the name of searchbased methods.
WANG Ning , PAN Huizhong , LIU Xiang , TANG Linhao
2017, 45(08):1160-1166. DOI: 10.11908/j.issn.0253-374x.2017.08.009
Abstract:On the basis of the complex social network theory and consumer decisionmaking theory, a forecasting model of electric vehicle (EV) market acceptance was developed based on the small world network, and the adoption and diffusion process of EVs in social network was simulated through Netlogo software. The simulation results indicate that the EV market acceptance are decided by both the individual preferences and the social network utility and the local network utility show greater influence than the global network utility. Furthermore, selecting the opinion leaders as the initial adopters, increasing the proportion of initial adopters and reducing the purchase threshold of consumers can help to promote the adoption of EVs.
CUI Wenshi , YANG Zhigang , WANG Guojun
2017, 45(08):1167-1173. DOI: 10.11908/j.issn.0253-374x.2017.08.010
Abstract:Based on Largeeddy simulation, influences of driving frequency on aerodynamic drag of a threedimensional ground vehicle and flowcontrol mechanism was studied. The results of flow analysis indicate that when synthetic jet array is located at the junction of the roof and the slant, drag reduction is realized with different frequencies. When driving frequency is lower than 90Hz, the aerodynamic drag increases with the driving frequency raise. When the frequency is more than 90Hz, the aerodynamic drag decreases with the frequency increase. While the aerodynamic drag fail to decrease with the frequency 1500Hz. The difference in the recirculation zone and the distribution of Reynolds stress contributes to the variation trend of the aerodynamic drag with different driving frequency. Frequency spectrum analysis reveals that the dynamic attachment flow on the slant is controlled by synthetic jet array with different driving frequency, so that the peak frequency of power spectral density of velocity, surface pressure and aerodynamic drag is related to driving frequency.
GONG Dao , MA Menglin , DENG Hai , ZHOU Jinsong
2017, 45(08):1174-1182. DOI: 10.11908/j.issn.0253-374x.2017.08.011
Abstract:For the problem of the vibration on the floor structure in an electric multiple unit (EMU) train when running at a high speed, insitu tests are carried out. Vibration transmission analysis and ride comfort analysis show that the vibration transfers from the steel structure to the floor structure is amplified in the frequency range from 20 Hz to 50 Hz, which is the sensitive frequency range that covers the human legs. To study the floor vibration amplification mechanism, a finite element model of the railway vehicle car body which includes the floor structure is established and verified. The results of the finite element analysis show that due to the improper stiffness of the original elastic support components, the frequencies of the eigenmodes of the floor structure close to those of the steel structure, which leads to the resonance phenomenon between them, then the floor vibration energy is enlarged. Finally, the optimization of the elastic support stiffness parameters is studied and verified by the test. The test results show that the optimized design effectively solves the vibration problem of the floor structure.
2017, 45(08):1183-1190. DOI: 10.11908/j.issn.0253-374x.2017.08.012
Abstract:Through the detailed derivation, this paper proves that the separability is objective existence and gives the form unity conclusion in the condition of the faultseparation about serial linear system and serial nonlinear system when exist the process noise. This paper also combines the wheels bearing fault of 552732QT electric locomotive, Shao guan 8 electric locomotives, the locomotive SS4G0446 of the concrete practice of the fault isolation.
LI Aiping , ZHANG Yanhong , GUO Haitao , Xu Liyun
2017, 45(08):1191-1197. DOI: 10.11908/j.issn.0253-374x.2017.08.013
Abstract:In this study, an optimization method is proposed based on JIT, to divide station group and arrange the distribution vehicles. In order to eliminate case that assembly line production process was shut down due to material shortage, with the capacity of distribution vehicles and distribution timewindow as the constraint, a model is developed, taking the full load ratio of distribution vehicles and station material requirement urgency as the optimization goal. Genetic algorithm is used to solve the model to optimize the total number of daily deliveries, which consequently give the plan of distribution of work station groups and vehicle scheduling. At last, the feasibility and effectiveness of this method was proved by the verification of example. Key words: mixedflow assembly line; material distribution; Justintime(JIT); station groups division; full load ratio; genetic algorithm
2017, 45(08):1198-1203. DOI: 10.11908/j.issn.0253-374x.2017.08.014
Abstract:This paper illustrated a source identification method in air duct system, aiming at detecting contaminant source within a short period of time after a bioterrorist attack. The method was based on genetic algorithm (GA) with minimal difference between calculated concentration and measured concentration as fitness function. We established a database of calculated concentration of sensors considering different releasing scenarios. Then we discussed the impact of the number of sensors, the location and measurement time of sensors, the capability of sensors, and the distance between nodes on the overall average relative error of inversion results (ξ). Results of a case study showed that the ξ decreased as more sensors were set in the ventilation system. The optimized number of sensors in this case was supposed three, considering both the decrement provided by each sensor and the high cost of each sensor. Meanwhile, the convergence generations were few while the convergence time was short. Then, the impact of sensor location and detection time on the ξ was coupled. The inversed source location x0 is sensitive to the time interval of feedback data but nonsensitive to the detecting error of sensors. Finally, there existed an appropriate number of nodes distance in air duct system, which gave consideration to lower calculated load and global optimization.
SU Xing , LI Hang , ZHANG Xu , SONG Bo
2017, 45(08):1204-1208. DOI: 10.11908/j.issn.0253-374x.2017.08.015
Abstract:A life cycle inventory analysis model for all life stages of solarassisted straw biogas system is developed, including raw materials acquisition, construction, straw transportation, operation and maintenance, biogas using and eventually waste management. Based on onsite investigation and measurement of a solarassisted straw biogas project, the life cycle fossil energy consumption and carbon emissions are calculated. The results show that the fossil energy consumption of the solar assisted biogas system is 0.173 MJ?MJ-1, and the carbon emission is 0.121kgCO2eq?MJ-1. When compared to natural gas, the fossil energy consumption of straw biogas is only 15.6% of the natural gas, the carbon emissions is 55% higher than that of the natural gas. The life cycle carbon emissions of solar assisted biogas system is 59.7% lower than straw burning.
2017, 45(08):1209-1217. DOI: 10.11908/j.issn.0253-374x.2017.08.016
Abstract:This paper investigates a compasslike passive dynamic walking model. Horizontal and vertical DOFs (degrees of freedom) are designed at the stance foot to calculate the normal and friction forces, and describe the pushoff and heelstrike processes. The passive dynamic walking gaits are calculated, and the local and global stabilities are analyzed. The results show that the walking gait is stable when the maximal absolute eigenvalue of the Jacobian is within the unit circle and the initial conditions of the walking gait is within the basin of attraction. These studies can not only provide guidance for understanding the motion mechanism of biped walking, but also help us for designing stable and efficient biped robot. For example, mechanical parameters improvement and efficient control strategy design.
CHEN Naijin , FENG Zhiyong , JIANG Jianhui , HE Ruixiang , WANG Zhen
2017, 45(08):1218-1226. DOI: 10.11908/j.issn.0253-374x.2017.08.017
Abstract:As for the problem of coarsegrained cell array pipeline mapping, this paper designed three row pipeline architecture array, analyzed their execution step, and presented a universal pipeline mapping(PM) algorithm for row pipeline array. This algorithm had comprehensive considered multilevel iteration initiation interval, communication costs between blocks, block reconfigurable costs and etc. The experimental results of a set of benchmark programs show the rationality of the algorithm. Comparing with multiobjective optimization map(MOM), the average execution total cycles of PM saved by 4.0%(reconfigurable cell array, RCA4×4) and 4.3%(reconfigurable cell array, RCA8×8). Comparing with epimorphism map (EPIMap) algorithm, the average execution total cycles of PM saved by 52.1%(RCA4×4) and 56.2%(RCA8×8).
WANG Junli , LIU Xianhui , GUAN Min
2017, 45(08):1227-1232. DOI: 10.11908/j.issn.0253-374x.2017.08.018
Abstract:When Social Network helps people build various social networking applications, a large number of user information and sensitive data will be collected in the mean time, and through the analysis of these data, some potential privacy information may be disclosed. At present, differential privacy protection model provides a rigorous and quantitative representation of the risk of privacy disclosure, which greatly guarantees the availability of data. In this paper, a generation model of social network publication graph is designed to meet the differential privacy protection. First the social network structure is represented as a graph model, and the original graph is classified into multiple subgraphs according to the characteristics of nodes. Then intensive regional of every subgraph is divided with a Quadtree method, noises of differential privacy protection are added into leaf nodes of the trees, and publication graph is generated by the way of subgraph reconstruction,. Finally, the feasibility and usefulness of the model is verified by the statistical analysis, such as the degree distribution, the shortest path and the clustering coefficient.
2017, 45(08):1233-1239. DOI: 10.11908/j.issn.0253-374x.2017.08.019
Abstract:Based on the statistics and collection of historical data, 18 surface characteristics of patients with pelvic fractures were selected. Bayesian network based on K2 algorithm was used to mine the causal relationship between the 18 surface characteristics, also between the surface characteristics and the pelvic fracture types. Different node ordering strategies were designed to analyze the influence on algorithm performance. Based on the stability of the pelvis, pelvic fracture was divided into A, B and C 3 types. Then found the features associated with each type of pelvic fracture, which was the basis of judgment. Based on the analysis of surface characteristics and pelvic fracture types, preliminary classification were made by means of early observation and simple examination.
FAN Qingzhai , FANG Xiaochun , LIANG Yueliang
2017, 45(08):1240-1242. DOI: 10.11908/j.issn.0253-374x.2017.08.020
Abstract:Let 0→J→A→B→0 be a quasidiagonal extension. We show the following results: ① suppose that J and B have the weakly comparison properties, then A has the weakly comparison property. ② suppose that J and B have the strictly cancellation properties, then A has the strictly cancellation property. ③ suppose that J and B have the nunperforated properties , then A has the nunperforated property.
CHEN Rongsan , SU Meng , ZOU Min , XIAO Li
2017, 45(08):1243. DOI: 10.11908/j.issn.0253-374x.2017.08.021
Abstract:Mao Dekang et al developed an entropy scheme for computing one dimensional hyperbolic conservation equations, which has a super convergence property and is suitable for long time numerical computation. But the entropy scheme does not satisfy the maximum principle. Overshooting or undershooting may occur in the vicinity of maximum or minimum points. In this work, numerical simulations of one dimensional and two dimensional linear advection equations are carried out. The numerical results show that the proposed scheme does not lead to overshooting or undershooting, moreover, nonphysical oscillations do not occur.
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