Abstract:Instead of traditional cubic Hermitian interpolation function, axial force is considered in element deformation in this paper, and a fourth order interpolation function is employed to form a new beamcolumn element considering thermal effect. Influence of element deformation on equilibrium equation and geometric equation, and influence of temperature on material properties and strain formulation are considered in new element, known as secondorder effect and bowing effect. A finite element program was written to verify the efficiency and accuracy of the new element against B23 in ABAQUS. It is concluded that the element number can be greatly reduced under the same accurate condition, and be superior in dealing with limit analysis, such as catenary effect of beam in fire and nonlinear progressive collapse analysis in fire.

Abstract:Tests were conducted on six concretefilled Tshaped steel tube (CFTST) stubs to investigate the characters of the deformation, failure modes and the bearing capacity of this kind of composite columns. The parameters taken into consideration in the test included the depth to thickness ratio of steel plates, the cross sectional depth to width ratio of the specimens. Experiment indicated that the bearing capacities of CFLST columns were not improved effectively, but the ductility were increased considerably, due to the fact that the local buckling mode of steel tubes were altered by the core concrete. It was also observed that the outward corners of steel tubes gave the greater confinement to concrete, and the inner corners almost failed to confine the core concrete due to the separation between the steel plate and the core concrete; hence CFTST stub columns failed in the local buckling of the wider steel plate and the crushing of concrete in the region of local buckling and inner corner. Test results showed that the decrease of the depth to thickness ratio of the flange plates of the steel tubes could postpone the occurrence of the initial local bucking in the wider steel plate, strengthen the confinement effects of steel tubes on concrete, and enhance the bearing capacity and ductility of the CFTST columns. Finally, the applicability of the methods in current specifications or codes, national and abroad, for calculating the bearing capacity of specimens was discussed.

Abstract:In order to investigate the effect of creep in high strength Q460 steel on the fire resistance of structures, creeptime curves for high strength Q460 steel under various temperature and stress was tested by using creep testing setup. According to the test data, creep models for high strength Q460 steel were proposed based on current creep models. The fire resistance of axially compressed high strength Q460 steel column was analyzed by employing finite element modeling after taking material properties and creep at elevated temperatures into consideration. The study shows that the creep deformation under the action of temperature and stress in high strength Q460 steel is significant, and at the same temperature and time, the creep increase obviously with rise of stress. After considering the effect of creep, fire duration of steel column decrease seriously under the fire exposure to ISO834 standard temperature curve. At a certain temperature, there is a pronounced reduction in load bearing capacity of steel column with the increase of time for fire exposure. Therefore, in the design of load bearing capacity of steel column, the time lasting in fire should be taken into consideration.

Abstract:Firstly, the Mehler’s formula, an equivalent series expansion of the bivariate normal probability density function (PDF), is introduced into the original equation with respect to the equivalent correlation coefficients, which is defined in the two dimensional dependent normal space. Then the equivalent algebraic equation with infinite terms is deduced straightforwardly, together with its convergence property. Theoretically, this work can be treated as the improvement of the Nataf transformation. Meanwhile, an iterative method for approximate solutions of equivalent correlation coefficients is proposed based on the truncated algebraic equation. Without the integral of bivariate normal PDF and with the merits of the reusability of coefficients of algebraic equations, the proposed method is of wide applicability, high efficiency and high precision. Lastly, the accuracy and rationality of this method are verified by examples.

Abstract:In order to study the effect of ambient temperature on bond behavior of Carbon Fiber Reinforced Polymer (CFRP)toconcrete joints at high temperatures, structural adhesives with different curing schedules were tested at different temperatures, and the shear performances of adhesive were investigated in the aspects of strength and stiffness. It was concluded that the glass transition temperature of the adhesive plays an important role for the bond behavior at high temperatures. When the temperature was near the glass transition temperature, bond behavior of structural adhesive has suffered a serious drop. Further, based on the bondslip relationship of FRP to concrete bonded joints at normal temperature, a simple calculation method was brought to derive the twoparameter bondslip relationship at high temperature. Considering the effect of glass transition temperature, normalized relational models for bond strength, the ultimate load and initial stiffness at high temperature are presented.

Abstract:The transparent soil was developed to model clayey soil, which was composed by amorphous silica powder, white mineral oil and dodecane mixture (2.5∶1 by volume). Based on the consolidated quick direct shear tests of 120 transparent soil samples with different stress states and normal consolidated compression tests, the shear strength under different stress states was given, also the strength and deformation properties were studied and showed high similarity to clayey soil. The loadingsettlement curves, ultimate bearing capacity, and velocity field displacement field were obtained by plate loading tests with the same settlement rates. The feasibility of using transparent soil to model clayey soil was finally verified by comparing with some known results.

Abstract:Taking water distribution network’s annual reduced cost as optimization object and seismic reliability as optimization restriction, a network topology optimization model is established. Then, an automatic generation strategy based on the existed road information is proposed. Combining with ring network generation method and automatic generation strategy, three approaches, a genetic algorithm, a simulated annealing genetic algorithm and a particle swarm algorithm, are employed to solve the seismic optimization model. Two networks are optimized using three algorithms and a comparative study is performed. The comparison indicates that the simulated annealing genetic algorithm performs the best.

Abstract:By means of integrated model including suspend curtain wall support structure (CWSS) and main structure, relative deformation and its effect on CWSS are analyzed under horizontal earthquake and wind load. And the response of vertical nonuniform deformation, internal forces and acceleration of CWSS are also studied under vertical earthquake in detail.Analysis results shown that, Under horizontal loads, vertical relative deformation between main structure and ring beam will lead to additional moments of radial strut. Setting the sliding structure in the end of radial strut can reduce the additional moment and ensure service of curtain wall safety. Under vertical earthquake, a larger nouniform deformation which have an adverse effects on plates, additional axial force of sag rods and significant vertical acceleration response of ring beam will be produced. In the design process, all above adverse factors should be evaluated to ensure the safety of curtain wall system under vertical earthquake.

Abstract:Using the high fidelity Tongji University driving simulator with 8 degrees of freedom, this study examined impacts of situational urgency on drivers’ collision avoidance behaviors. By combining different initial headways (<1.0 s, ［1.0 s, 1.5 s), ［1.5 s, 2.5 s］) and different lead vehicle deceleration rates (0.30g, 0.50g, 0.75g), rearend collision scenarios with different levels of situational urgency were established. Drivers’ perception response times (PRT), throttle release response times, throttle to brake transition times, brake delays, maximum brake pedal pressures and peak decelerations were compared across different levels of situational urgency. Results show: ①At higher situational urgency, drivers release the accelerator faster, and brake to maximum more quickly and forcefully; ②PRT was near 1.2 s when the initial headway was round 1.5 s, but PRT increased dramatically when initial headways were larger than 2.5 s, and could even reach 3 s; ③Transition time between throttle release and brake initiation is about 0.8 s and is not affected by situational urgency; ④At lower situational urgency, multistage braking behavior leads to longer delay from brake initiation to full braking.

Abstract:In order to study additional cumulative deformation and dynamic strength stability of railway subgrade under effect of heavy axle load train for existing railway lines, typical subgrade soil was selected to conduct cyclic triaxial tests to obtain the variations of cumulative plastic deformation and threshold stress under various physical states and cyclic loading conditions. Consequently, the prediction formula of cumulative strain was established. On this basis, by dynamic finite element method and layerwise summation method, dynamic stress and additional settlement of subgrade under heavy axle load were calculated. The conclusions are as follows: subgrade settlement rises rapidly with increasing in the axle load in conditions of low compaction or high saturation, and moreover, the settlement rises significantly when axle load exceeds 27t; but when the compaction coefficient is larger than a certain value, the increase of axle load has a smaller effect on subgrade settlement; the influential depth of additional settlement in subgrade under heavy axle load is mainly within 2.5m from subgrade surface, especially within 1.0m; under heavy axle load, subgrade may generate unacceptable permanent deformation even it meets the threshold stress condition. To reduce subgrade additional deformation and its duration under heavy axle load, the compaction coefficient or strength of subgrade should be improved.

Abstract:Based on field investigation and experimental data, extended finite element method was introduced to establish uniform stress model and non uniform stress model under adverse conditions. Horizontal, vertical micro cracks, single and multiple cracks were set up to study the crack development process of the fastener screw spike. The result shows that due to abrupt size change in the screw spike combining site of the head and screw, there is large stress concentration, easily generates micro cracks and then lateral extends, eventually breakdown under longterm train load. Simulation resultswere in conformity with actual fastener screw spike fracture form, so the extended finite element method is very suitable for fastener spike fracture process analysis. In addition, in order to avoid and reduce the screw spike rupture occurring, 13 kinds of working condition were studied about fastener screw spike shoulder transition arc setting. The result shows that the ideal arc radius is 1.6 mm for T30×155 type fastener screw spike, and the maximum stress will be reduced by 40% relative to without transition arc.

Abstract:The impacts of urban rail transit on residential property values were classified into traffic effects and agglomeration effects, both of which could be measured by the accessibility improvement model. A case on 16 stations of Shanghai Metro Line 11 was studied to verify the model by analyzing the relationships between the accessibility improvement values and the residential property appreciations. The results indicate that the residential property appreciation is about 5 times the accessibility improvement value per year and this has occurred as soon as the stations open due to the expectation effect. Furthermore, because of the different locations of the stations, the impacts are markedly different, ranging from about 2 percent in the city center to about 18 percent in suburban areas. This method can provide suggestions for urban rail transit value capture and landuse planning of areas surrounding the stations.

Abstract:According to the demand changes from the competitive market, machine tools and other resources could be added or removed from manufacturing or assembling lines to meet different outputs. In the case of production reduction, appropriate equipment were selected and removed to change the capacity of the existing manufacturing line based on the removing principle. An improved immune genetic algorithm based on vaccine autonomous obtaining and updating was proposed, crossover and mutation operation in traditional genetic algorithm were changed to transfer and adjustment between different gene locations and transfer of operations between different stations can be realized. The objectives of reconfigurable process planning was to minimize the bottleneck cycle time and imbalance among stations. Finally, a cylinder block case was illustrated to verify the effectiveness of the given method.

Abstract:Operating unit ratio (OUR) was addressed to analyse behavior regulation of variable refrigerant flow (VRF) system. Correspondingly one office building located in Shanghai was investigated to get data of one year including cooling and heating periods. Statistical results showed that maximum value of OUR was about 60% during heating period, the corresponding energy consumption of VRF keeps in line with the increase of OUR and the maximum range value of sample data during statistical intervals was about 0.4. As to the energy consumption in cooling period, it shows exponential variation (ie. flat at beginning and steep in the subsequent) with the increase of OUR, the maximum range value of sample data during statistical intervals was about 0.55. Data envelope analyse (DEA) and Parzen window were used to further investigate the variation characteristics of behavior regulation. Results showed that probability of effective behavior regulation during heating period was about 0.54 and that corresponding value during cooling period was about 0.44.

Abstract:Based on the characteristic of distributed drive electric vehicles that the torque of motors and hydraulic brake system can be controlled, an algorithm combing motors and hydraulic system was proposed with the aim of stability control. The algorithm used a hierarchical control structure. The upper layer calculates the generalized force based on the driver input and vehicle state. Under the constraint of actuators and speed and the influence of tire coupling characteristic, the lower layer takes quadratic programming method to optimize torque allocation. Finally the algorithm was simulated on CARSIM and MATLAB platform and verified by vehicle tests. The results of simulations and tests show that the algorithm can improve the stability. And the control result of the algorithm of motors and hydraulic brake system is better than that of motors.

Abstract:In order to obtain the influence of underbody structures on flow field and aerodynamic drag optimization laws of high speed train, the computational fluid dynamic and the orthogonal experimental analysis methods were adopted to studied underbody flow field, wake and the optimization law in complex train model. The results indicated that the pressure coefficient drops 0.06 in nose region of the tail car, and bogies moved the flow separation of the tail car ahead. The distances and the angle between antisymmetric wake vortices cores increased. The simplified topology model in concept design was suitable for aerodynamic optimization in complex train model design. However underbody structures decreased the optimization range of the head car, and increased the parameter optimization range of the tail car. The drag reduction of the head car should focus on bogie sections, and drag reduction of the tail car was more sensitive to streamline length.

Abstract:Largeeddy simulation (LES) was used to study the unsteady flow around Ahmed body in both natural and controlled flow. The simulation results were validated against the experimental data. The meantime results indicated that flow separation could be suppressed when a synthetic jet actuator was located at the junction of the roof and the slant, which could result in a smaller separation zone and aerodynamic drag reduction. Spectrum analyses revealed that with the momentum coefficient of excitation is more than 1.0×10-4，the peak frequency of power spectral density surface pressure on the slant，velocity and vortices in the recirculation zone, as well as drag coefficient is related to driving frequency. The transient flow results suggest that the interaction between the jet and the flow lead to periodical changes of the peak and trough of drag coefficient.

Abstract:Finlets with varied length and height on squareback body based on Fiat New Panda were investigated firstly both by computational and experimental ways. The scale wind tunnel tests were performed to obtain the drag coefficient and lift coefficient and the correlations with computational fluid dynamics based on kε turbulent model were studied. It indicated that finlets along the whole C pillar could reduce both the drag coefficient and lift coefficient of a square back body. Finlets could delay air flow separation around C pillars and then decreased the turbulence kinetic energy in the wake. More pressure recovery was realized on the square back body to reduce the pressure gradient of the car body and the drag coefficient can be decreased as a result. Then the finlets with varied figures were simulated and got the results that the all the finlets can reduce the drag and lift coefficient but finlet with rectangle figure was the best.

Abstract:Based on the energy dissipation modes and the ideal folding mechanism presented by Wierzbicki and Abramowicz, a modified energy balance equation was developed for the square tube with strengthened ridgelines subjected to quasistatic axial crushing by introducing a yield strength ratio between ridgeline and plate. Then a theoretical prediction formula of mean crushing force was also derived. CAE (Computer Aided Engineering) numerical simulation completely reproduced the plastic deformation process of a new folding element of square tube with strengthened ridgelines during stable crushing stage. Comparisons between simulation results and theoretical solutions show that the theoretical formula can correctly predict the mean crushing force for square tube with strengthened ridgelines subjected to quasistatic axial crushing, and the max deviation is lower than 4.3%. Secondly, for a specific square tube whose length, width and thickness of cross section is 56mm, 56mm and 1.0mm respectively, four strengthened ridgelines which only occupy 9.09% of perimeter of the cross section can increase its mean crushing force by 53.8%.

Abstract:The key elements in cadastral management, which are the geometric spatial information and attributes of parcels, have typical spatiotemporal characteristics. The current researches on the spatiotemporal changes of parcels mainly focus on the expression of a single aspect of the cadastral parcel. However, the expression of the spatiotemporal changes of all the attributes and geometric spatial information of the parcels need to be strengthened. Meanwhile, little attention is paid to the expression of spatiotemporal changes of parcels based on moving objects theory. And the expression of synchronous changes of multiple objects needs to be further studied. In this paper, as to the two mentioned problems above, the types of spatiotemporal changes of parcels are analyzed. And the method to express the spatiotemporal changes of geometric spatial information and attributes (single attribute and ownership) of a single parcel based on moving point objects is proposed. At the same time, the method to describe the spatiotemporal changes of multiple parcels based on events is presented in this paper. Furthermore, the prototype system of spatiotemporal management of cadastral parcels is developed in this study, which proves the feasibility and efficiency of the proposed methods.

Abstract:In view of the multiscale property of deflection and the periodicity under temperature load, a strategy was proposed to separate the deflection and extract the longterm trend, which combines Welch method with Center Moving Averages Method. A prediction model of the deformation was established based on ARIMA model. Taking Bridge of Huanggang Yangtze River as an example to issue the correlation between temperature and deflection, and test of numerical simulation was made to validate the effectiveness of the algorithm. Processing and analysis of the measured data indicate that the approach of this article has high precision and reliability which could provide data support for damage identification of bridge.

Abstract:The isostatic response function was used to calculate the effective elastic thickness of lithosphere profile from East China Sea to East Mariana Basin.The Ryukyu trench and Mariana trench topography toward the ocean side was also used to validate elastic thickness based on the elastic plate bending model with stress load on the toe of plate,and analyzed the effective elastic thickness results of different sections in conjunction with seismic sounding,geological and geophysical research results. Results demonstrate that Two effective elastic thickness values estimated from the isostatic response function curves,large effective elastic thickness values are close,between 20~25km,the lager effective elastic thickness values reflect the regional thermal state of the marine lithosphere elastic characteristics.The smaller effective elastic thickness values reflect the geological process characteristics of different sections.

Abstract:This paper presents numerical simulations to investigate the reintensification of a tropical cyclone that formed to the north coast of the Northern Territory of Australia in January 2006 (NT2006) with an asymmetric view. The azimuthally averaged tangential momentum equation is partitioned into mean and eddy terms, and then the magnitudes of the eddy momentum fluxes and subgrid momentum fluxes are compared. The results show that the mean vertical advection of tangential momentum contributes most to the spin up of the azimuthal mean tangential wind, and in the middleupper troposphere the eddy momentum fluxes partly contribute to the spin up of the vortex as well. The comparison of momentum fluxes indicates that the resolved eddy momentum fluxes are much larger than the subgrid momentum fluxes and they are quite different from each other in pattern.