Abstract:The relationship between mesoscopic and macroscopic material properties are presented based on the multi-scale method. It is equal to say that the macroscopic damage evolution can bee obtained from the micro-cell simulation results. Then, two kinds of typical micro-cells are generated for the macroscopic tensile and shear damage evolution. To apply the damage evolution from the micro-cell analysis to the engineering simulations, a pragmatic damage evolution law is put forwards for the tensile and shear damage and the damage evolution parameters can be obtained. Comparison between simulation and the experimental results are given to testify the validity of the present model. It is demonstrated that the model agrees well with the experimental results.

Abstract:Embedded channel joint of precast concrete beam is a new type of joint system which can be applied to prefabricated energy dissipation and seismic reduction systems. Static bearing tests of 12 specimens were carried out, which considered the influence of the length of the embedded channel steel, the stirrup spacing, the cavity in the midspan of the beam, and the eccentricity of the channel steel. Two kinds of failure modes were obtained: the lever-out of the channel steel and the crushing of the beam-end concrete. The test results revealed the following: the bearing capacity of the joint increased with the increase of the length of the embedded channel steel; stirrup densification could significantly improve the bearing and deformation capacity; the cavity in the midspan of the beam had little influence on the bearing and deformation capacity of the joint; the eccentricity of the channel steel led to the additional torsion, which lowered the capacity of the joint. FEM models were established, and they were verified by comparing the test results and the FEM results, which has built a solid foundation for further research.

Abstract:It is specified that the maximum shear force born by the frame calculated according to the stiffness in the frame-tube structure should not be less than 10% of the total base shear in the Chinese national specification technical points of the special review for seismic design of super high rise buildings. However, due to some reasons, such as the building layout, this requirement sometimes is difficult to meet in engineering practice. This requirement is controversial. In order to investigate its rationality, five RC frame-tube structures were designed, and main variables are the stiffness of the frame, the strength of the frame and the type of coupling beams. Then the elastic response spectrum analysis and the time-history analysis under small, medium and strong earthquakes were carried out to assess the seismic responses of each structure. It is found that when the maximum shear force born by the frame calculated according to the stiffness is less than 10% of the total base shear amplifying the stiffness of the frame is not economic but leads to worse seismic performance. Amplifying the strength of the frame can reduce the damage of frame beams and improve the seismic performance of structure, but it can not form effective "strong column-weak beam" mechanism. Adopting coupling beams with large width and replaceable coupling beams can both lead to the dual system of core tube. The enhancement of energy dissipation capacity of coupling beams can protect the shear wall and outer frame effectively, and significantly improve the seismic performance of the structure.

Abstract:In order to obtain the behavior of high strength steel endplate connections in fire, full-scale tests on 7 joints were conducted at elevated temperature 550℃. Based on the test results, a FEM analysis on high strength steel endplate connections under fire conditions was carried out by ABAQUS. Details of the numerical modelling, such as mesh generation, element type, contact interaction, analysis process and failure criterion based on deformation, are presented. Herein the moment–rotation relationship, failure mode and stress state as well as yield line pattern of high strength endplate connections both at ambient temperature and in fire are revealed. Besides, the validations of the numerical modelling against all representative experimental results show that good agreements exist.

Abstract:In order to study the effect law of deck pavement roughness on dynamic response of concrete bridge deck pavement under vehicle random load, vehicle dynamic load was simulated by MATLAB software based on 2-DOF 1/4vehicle model and then applied to 3-D finite entity model of vehicle-bridge-deck pavement coupling vibration through ANSYS software. The results shows that: compared with stress time-history response of a fixed node, the response of extreme value of pavement stress can not only reflect the random character of vehicle load but obtain the most unfavorable response of pavement; at a certain roughness, the magnification coefficient of different stresses are very similar and when deck pavement is uneven, the extreme value of pavement stress are more than one time larger than absolutely smooth pavement; if a set of complete and accurate assessment criteria could be developed for bridge deck pavement, the stress state of deck pavement could be controlled from a macroscopic perspective by monitoring surface roughness.

Abstract:A system of radial consolidation combined plastic wick drain and vacuum preloading is one of the most popular methods of soft ground improvement, which not only can reduce the height of surcharge preloading on dam, but also can reduce the lateral displacement of soil. The consolidation solution of plastic wick drains and vacuum preloading using nonlinear relationships of this paper can be greatly applied to forecast and analysis this kind of ground improvement. In the process of analytical solution, the relationship between void ratio and mean effective stress, horizontal permeability coefficient under one-dimensional consolidation is considered to be semi logarithmic linear, rather than previously thought one-dimensional linear. Because of disturbing on soil around PVD in smear zone, permeability around PVD in smear zone is distributed in parabolic form. Besides, the effect of vacuum preloading on consolidation is considered. Correctness of this analytical solution is verified through degradation method and compared with test results. Finally, the effects of , C_k/C_c, are analyzed on consolidation. The results indicate that consolidation rate increases with the increasing of C_k/C_c and decreasing of .

Abstract:Abstract: The effective consolidation stress method was applicated to analyze the stability of reinforced embankment over soft foundation soils, considering the characteristics of staged-filling subgrade in construction. Based on the working mechanism of reinforced cushion, its two principles in improving the stability of embankment were illustrated by analyzing the tensile force of geosynthetics and the overall stability analysis of the embankment with limit equilibrium method. The results showed that not only the tensile force of geosynthetics can resist the sliding force directly on the tangent of potential failure surface, but its normal component also can enhance the shear strength of foundation soils. Taking the function of reinforced cushion and the consolidation of soft foundation soils during construction process into account, a modified formula of effective consolidation stress method was proposed, which can be used to analyze the stability of reinforced embankment over soft foundation soils. In addition, its features and applicability were studied by the calculation and analysis of engineering projects.

Abstract:Traffic Incidents such as crashes and vehicle break down have significant impacts on urban expressway operation. With a well-developed incident duration prediction model, the roadside service and operational efficiency of urban expressways could be improved. In this study, instead of utilizing frequently adopted decision tree and survival analysis method to establish the incident duration analysis model, random survival forests model is employed. The random survival forests model can not only overcome the disadvantage of over-fitting problems of decision tree algorithm, but also break through the limitation of restrictive assumptions and solve the problem of identifying interaction of the covariates in traditional survival analysis. This study is conducted based on traffic incident data of Shanghai urban expressways. The traffic incident data is combined with the road geometry data, traffic operation data, and weather condition information; where 80% data is used as training dataset and the remaining 20% as testing dataset. The results show that incident type, length of road, location, remained lane number and traffic volume have significant impacts on incident duration; and the prediction results based on testing dataset indicate that the random survival forests modelis more accurate than random forests model.

Abstract:Non-work travel in the proportion of the structure of travel is on the rise. Structural equation modeling (SEM) was adopted to analyze the influence mechanism of residents’ non-work activity and travel behavior based on the Shanghai Household Travel Survey. The results of SEM show that socio-demographic characteristics and neighborhood features both affect residents’ non-work activity and travel, but neighborhood features have stronger influence than socio-demographic characteristics. The most significant characteristic in individual is the employment situation. The most significant characteristic in household is the number of automobiles. And the most significant characteristic in neighborhood is the coverage of neighborhood services.

Abstract:Characteristics of vehicle fuel/emissions are related to vehicle driving mode. To improve the accuracy of vehicle fuel/emissions estimation, a modal-activity based vehicle fuel/emissions estimation method is proposed using spare mobile sensor data. The proposed method is calibrated and validated using the real-world vehicle trajectory data. Result reveals that our proposed method shows good performance on vehicle fuel/emissions estimation. The findings of our research can enhance the applicability of spare mobile sensor data and provide a new methodology to estimate vehicle fuel/emissions.

Abstract:Turnback capacity have become a major concern for the line capacity of rail transit. Take a rail transit stub-end terminal with four-tail tracks as background, based on N-track integrated model, a mixed integer programming optimization model is formed to estimate the turnback capacity and the track occupation strategies with the objective of minimizing occupation times of trains. Operations and design parameters such as tail track allocation strategies, train layover time, homogeneity of trains are also considered in this model. We illustrated our model using computational experiments drawn from the real rail transit line 16 in Shanghai and reached results which show that how the track occupation strategy, maximum layover time, homogeneity impact on turnback capacity.

Abstract:Fujian Province is the first ‘national ecological civilization experimental zone’ approved by the State Council of China. As the provincial capital, a good ecological environment for Fuzhou City is always expected. With the progress of urbanization, Fuzhou has witnessed a significant urban thermal environment (UTE) change, leading the city to be reputed by media as the top of the three new ‘furnace cities’ in China. To investigate the process of the city from a non-furnace city to a top furnace city in China, the dynamics of urban biophysical components of Fuzhou and the associated UTE between 1989 and 2013 have been analyzed by remote sensing technology. The result shows that the urban heat island (UHI) effect in Fuzhou greatly aggravates as the UHI Ratio Index (URI) of the city increases from 0.29 to 0.53 in the past 24 years. The spatiotemporal variation analysis on the basis of the thermal profiles reveals that the spatial structure of the UTE is greatly influenced by the spatial pattern of land cover types. On the whole, the increase and amalgamation of impervious surface patches, reduction and fragmentation of vegetation and water covers, and the blockage of the urban ventilation are the main factors contributing to the formation of the ‘furnace city’ of Fuzhou. The study provides a guidance and support for the mitigation of the UHI effect and the achievement of city’s healthy sustainable development.

Abstract:filtering loads of outdoor PM2.5 for all province capital of China are determined with the method of un-guarantee days. Filtering Concentration Days(FCD) is proposed with the analogy of the CDD and HDD. Based on PM2.5 concentrations dynamic data and the base concentration, the FCDs of all province capital are calculated. The relationship between FCD and the filtering load of outdoor PM2.5 is analyzed with a statistical way. The result shows: FCD is highly linear correlated with the filtering load of outdoor PM2.5 with P<0.01. And FCD can be used as the climatic indicator of the demand for filtering services. Besides it can provide a straightforward basis for the filtering system design.

Abstract:An experimental study on the flexural performance of ultra-high performance concrete (UHPC) without thermal curing was carried out via third-point bending tests. Based on the test results, discussions on how to effectively evaluate the flexural performance of UHPC were presented. The third-point bending test results indicated that first cracking point of UHPC was hard to be determined, while significant “deflection hardening” behavior was noticed. Combined with the load-deflection curves of UHPC with different steel fiber dosage, both advantages and disadvantages of three evaluation methods of ASTM C1018, JSCE SF4 and ASTM C1609 commonly used were discussed. The results showed that the flexural strength related to different mid-span deflections given by ASTM C1609 can be regarded as more meaningful parameters for UHPC structure design, which can meet the various needs of the UHPC structural design.

Abstract:Split-body styling creates a new field of automotive exterior design which is different from uni-body styling, which has breakthrough meaning as for design, however the air drag will come up to be a new problem. Based on A segment vehicle as reference, it built split-body low-drag basic form, which was considered in the aspect of ergonomics so as to insure the engineering rationality. It started vehicle design with verified basic form. It transformed basic form into real car while keeping the form low-drag by adding details while taking aerodynamic simulation. Eventually, it found design methods related to both design and aerodynamics and obtained one low-drag split-body design proposal, CD of which is 0.2249.

Abstract:General situation of electric car design is analyzed and basic specifications are set. Based on the body of least drag, the paper start with a low-drag bionic shape to get the main body design. With comparison study of the electric car and traditional car design, the style of the new car is defined. Optimization for the essential parts of the car, such as the nose, wheel, etc., are developed on both design and aerodynamics. During the process, the styling, aerodynamics and thermal control are studied with coupling method. Finally a totally new low-drag electric car design is developed, as well as a full-scale hard model. The final 1:1 wind tunnel test result in a CD of 0.193, much better than the objective of CD 0.238.

Abstract:Based on numerical simulation, it created a 1:1 scaled model of the climate wind tunnel and the passenger car, to investigate the effect of climate wind tunnel blockage on the cooling system experiment, and analyze the air-side flowfield of cooling module and the frontal velocity profile. The results indicate that, along with the increase of blockage ratio, the velocity distribution on the windward surface of radiator will make a difference, but little change for the uniformity index of velocity distribution. As the blockage surpasses 0.486, the air mass flow through the radiator has an obvious decrease, even up to 5%. Due to the blockage effect, the frontal velocity profile exists an offset, which is inconsistent in different positions. Consequently, the climate wind tunnel needs to perform a blockage correction according to the different experimental targets.

Abstract:By wind tunnel test and numerical simulation, the regulation of horizontal tail contraction on aerodynamic drag reduction was studied. The results indicate that tail contraction raises pressure level of tail surface and reduces aerodynamic drag. Base on result of reliable numerical simulation, the changes of wake structure were studied. The research indicates that tail contraction provides additional kinetic energy for tail dead zone, suppresses formation and development of trailing vortex pair, reduces flow energy loss of wake and aerodynamic drag.

Abstract:Taking Ahmed body with flow control slot at special location of slanted surface for object, the mechanism and effect of steady blowing/suction methods belonging to active flow control concept were studied by using large eddy simulation that is proved accurate. Base on analysis of flow field data, the blowing control method results in fully separation on the slanted surface and enlarged recirculation zone around body with higher aerodynamic drag, although trailing vortex pair is eliminated. The suction control method eliminates and delays the production and development of spanwise vortices structure with lower aerodynamic drag, however trailing vortex pair remains unchanged.

Abstract:A heating system and a reasonable structure of the air duct structure are designed, to achieve the purpose of improving the passenger compartment thermal environment. The structural parameters of the heating system are optimized. Aiming at the four factors such as the chamfer radius of the air outlet, the angle between duct axis and X axis, the height of the outlet and the type of return air grille on the thermal environment of passenger compartment, according to the orthogonal test theory, the optimal design scheme is determined, and the optimal design scheme is that the chamfer radius of the air outlet is 60mm, the angle between duct axis and X axis is 110°, the height of the outlet is 570mm, the type of return air grille is Z-6-280×5. The CFD simulation of the optimal design is carried out, the temperature of heads and feet of driver, passenger 1 and passenger 2 are monitored, the result show that the heating system of the optimal design can greatly improve the thermal sensation of driver, passenger 1 and passenger 2.

Abstract:This paper takes recycling of Low Commercial Value High Environmental Impact (LCV-HEI) class EOL products as purpose; we put forward an evolutionary game model based on recycling EOL products and give an analysis about the operation mechanism of Closed-loop Supply Chain model for LCV- HEI class EOL products. We study the long-term evolution characteristics of OEM and EOL disposal center population under market mechanism; we analyze the strategy selection and stable equilibrium point of the two groups in the evolution process. The results reveal that OEM remanufacturing prices need to be controlled in a reasonable range. At this point, using (recycling, reuse) strategy become the only strategy to the EOL disposal center and OEM groups, which is more conducive to promote the EOL product recycling and reuse. And OEM group choose reuse strategies, no matter how the profits, the unit of government subsidies meet certain conditions, it can promote the evolution of the groups to form the only equilibrium point (1,1).

Abstract:It is common that outsourcing strategy causes risks like increase in indirect costs, information asymmetry, and reduction of control. In order to take the advantages of outsourcing strategy and reduce potential risks, supplier selection process plays an important role among each step of the supply chain management. Based on literature review, supplier selection criteria were divided into four categories, namely service quality, price and cost, communication and coordination, and R&D and innovation. And the alternative suppliers evaluation were ranked by using an extended VIKOR (VIseKriterijumska Optimizacija I Kompromisno Resenje) method with interval 2-tuple linguistic information. An empirical case study was provided to show the feasibility and practicability of the proposed interval 2-tuple linguistic VIKOR (ITL-VIKOR) method, including comparison with other three commonly used approaches. Results show that the proposed approach is able to handle several data processing problems like information distortion, ranking results repetition, analyzing quantitative and qualitative data at the same time, involving subjective and objective weight, as well as considering preference from decision makers.