Abstract:In order to quantitatively reveal the combination of steel and concrete interface, an analysis method was provided for the calculation of composite girder considering connectors, bond stress and friction in the interface between the steel and the concrete. The feasibility of the method was also verified through the experiment. This method was used to analyze the relationship between different steelconcrete connecting conditions and interface slip and also the effect of the present or not of the interface bonding on the mechanical behavior of the composite girder was analyzed. The results show that, the steelconcrete interface bonding effect has a tine effect on the stress of the concrete slab and steel girder, but has a large effect on the shear force of the connectors where the maximum effect can reach 25 percent under different loads.

Abstract:Formulas which were most commonly used to calculate interface shear strength specified in foreign codes were summarized, the contact interaction between the precast concrete layer and the concrete core is modelled using a cohesive property interaction to define the separation behavior between the two surfaces. The result shows that the tractionseparation models for surfaces can reflect the level of delamination and damage in interface between the precast concrete layer and the concrete core. There is small influence on ultimate bearing capacity of superimposed shear wall under different axial compression ratio, the degree of damage and delamination in the interface of superimposed shear walls with castinsitu boundary element is lower than the superimposed shear walls with prefabricated boundary element.

Abstract:In order to investigate the coldforming effect on yield strength distribution of coldformed thickwalled steel with open section, coupon test and axial compression test were carried out. Firstly, 5 types of coldformed lipped channel sections with thickness of 3, 8, 12 and 16mm, and two yield strength grades of Q235, Q345 were chosen to conduct coupon test for the web, flange, curling, corner parts, respectively, and a corresponding distribution model for the yield strength distribution of coldformed thickwalled steel with lipped channel section was put forward. Then, the axial compression tests of 5 stub columns with the same section as the coupon test were carried out for further investigation on the coldforming effect. Finally, the results of stub column test, the results based on the proposed yield strength distribution model, and the results based on the related codes in various countries were compared. It is shown that, the yield strength distribution of coldformed thickwalled steel with open section is greatly influenced by the coldforming effect, and mainly depends on the width to thickness ratio of the plate involved; the estimation based on the proposed yield strength distribution model is close to that based on of the codes in various countries, as well as the test results, although the latest is slightly larger. Moreover, among them, the results based on the Chinese code, GB 50018—2002, is closest to the experimental values with smallest variation coefficient, which means a best applicability.

Abstract:Based on the typical damage of laminated rubber bearing sliding for small to mediumspan girder bridges during the Wenchuan Earthquake, experimental study on the sliding frictional behavior between bearing and steel plate was carried out. Effects of vertical stress and sliding velocity on the bearing sliding behavior were investigated. Results showed that the bearing displayed an approximately linear elastic shear response before sliding. The nominal shear modulus of the bearing ranged between 700 and 1 100 kPa. The coefficient of sliding friction at bearingsteel plate interface was negatively related to the vertical stress, and positively related to the sliding velocity. A mechanical model of the sliding behavior between laminated rubber bearing and steel plate was then developed, considering the effect of various parameters.

Abstract:The problems of lined circular tunnel construction subject to nonhydrostatic initial stresses were considered, accounting for crosssection excavation, longitudinal advancement, and any installation time of the elastic liner. In the derivation, linear viscoelastic models were adopted to simulate the rheological properties of the rock, time dependent excavation process and fictitious stresses were considered to simulate sequential excavation and tunnel advancement, respectively. According to the complex variable method and Laplace transform technique, the boundary and compatibility conditions were expressed by the two potentials, and the equations with respect to the coefficients in potentials were established afterwards. The analytical solutions for stress and displacement were then provided for the whole construction process after the determination of the coefficients by solving these equations. A good agreement between results from Finite Element Method and the analytical solutions had been obtained. Based on analytical solutions, a comprehensive parametrical analyses were then carried out to investigate the distribution discipline of displacements and stresses of the rock, as well as the influence of liner installation time on displacements and stresses of the rock. According to presented solutions, a fast predicting system for the mechanical state of the rock can be obtained and the ones provide much convenient way for preliminary design of tunnel construction.

Abstract:The most of previous sediment settling velocity formulas were suitable for single sediment particle. Based on the previous research results on single sediment particle settling velocity laws and the experimental data of sediment particle cloud during the settlement process in water body, the formulas for calculating the settling velocity of sediment particle cloud were proposed by introducing two factors, i.e., the characteristic particle size of sediment particle cloud and additional particle size, to correct the existing single sediment particle settling velocity formulas. The settling velocity values of sediment particle cloud calculated by the corrected formulas were very close to the experimentally measured settling velocity values of sediment particle cloud, which indicates the corrected formula can be applied to calculate the settling velocity of sediment particle clouds.

Abstract:Wind is a nonstationary stochastic process, but the traditional time domain or frequency domain analytical procedure can’t quantify its nonstationary characteristics. A visual and quantitative signal analytical procedure was put forward, which was the recurrence quantification analytical procedure. In this procedure, there were no specific requirements for the stationary characteristics of system and the procedure was not sensitive to noise. Firstly, the nonstationary characteristics and other characteristics of the typical time series of hurricane Gustavo (2008) were obtained by utilizing phase space reconstruction techniques and recurrence plot theory. Thereafter, 6 recurrence quantification indexes were imported, which were recurrence rate, determinism, entropy, average diagonal line length, laminarity and trapping time and quantifies the signal characteristics of hurricane in the whole process of making landing, and defines one boundary for every index between hurricane signal and normal wind signal. Lastly, the procedure and all the indexes defined are verified by typhoon Muifa (1109). The result shows that the early hurricane has certain periodicity and stationarity; however, the nonlinearity and nonstationary are particularly salient for the middle hurricane; 6 indexes can distinguish the signal characteristics between hurricane and normal wind; recurrence quantification analytical procedure completely suitable for the wind signal researches, and can fully describe the nonstationary characteristics of wind signals.

Abstract:The process of collision avoidance under rearend scenarios can be divided into several stages (e.g., prebrake and postbrake). In each stage, different analysis perspectives (e.g., brake delay and brake intensity) exist, and different key time moments and measurements can be defined. Therefore, lots of parameters are involved in systematically describing drivers’ collision avoidance behaviors. Studies that focused on a certain parameter can only give information on a specified parameter rather than the underlying behavioral patterns behind the parameters. This study did dimension reduction analyses for the multiple parameters of collision avoidance behaviors, and investigated the impacts of situational urgency on each type of parameters. The high fidelity Tongji University driving simulator was used to test drivers’ collision avoidance behaviors under different initial headways (1.5 s, 2.5 s) and different lead vehicle (LV) deceleration rates (0.30g, 0.50g, 0.75g). Parameters characterizing drivers’ hazard perception, throttle releasing and braking process were recorded. Dimension reduction analyses on collision avoidance behaviors was conducted with principal component analysis, which generalized collision avoidance behaviors into three aspects: perception response, braking delay and braking intensity. Multivariate analysis of variance was applied to investigate how initial headway and LV deceleration affect these three aspects. Results showed that perception response was affected by both initial headways and LV deceleration; braking delay was affected by initial headway, LV deceleration and their interaction simultaneously; and braking intensity depended solely on lead vehicle’s deceleration. As situational urgency increased, drivers responded faster and braked to maximum more quickly, and braked harder.

Abstract:Firstly, curvature and torsion instead of traditional twodimensional (2D) horizontal and vertical indexes were used to describe the spatial geometric properties of highway alignment according to the curve theory of differential geometry. Then the vehicle was treated as a rigid body and a new motion model was established with the curvature and torsion as the control variables base on the Frenet Frame. Finally, an example was analyzed to demonstrate the influence of spatial geometric properties of an existing highway on vehicle kinematics. It is found that the setting of curvature plays a leading role in the spatial motion, while the torsion affects the motion less. The coupling effects of horizontal and vertical alignments were ignored during traditional design process, which led to the continuity degradation of curvature and torsion, and directly affected the smooth variation of vehicle motion and driving comfort.

Abstract:Traditional aircraft ground maneuver dynamic modeling always neglects the nonlinear characteristics of the shock absorbing system and makes simplifying assumptions on the aerodynamics. Thus, it is difficult to study complicated aircraft maneuvers. Experiment is direct and effective, but difficult to conduct and it’s cost is very high. A320, A330 and A380 virtual prototype models were developed in ADAMS/Aircraft and taxiing simulation was conducted by applying different roughness level of runway models which were generated according to the power spectral density equation in GB/T70311986. Simulation results show a good linear relationship between dynamic load and International Roughness Index (IRI), and magnitude of dynamic load increases firstly then decreases as taxiing speed increases. Moreover, dynamic load coefficient calculation formulas were proposed. The paper can be a reference for evauation, maintenance and mechanical properties research of airport pavement.

Abstract:Through dynamic shear rheological (DSR), repeated creep and recovery teat(RCRT) and bending beam rheological(BBR) test, the rheological behavior of polyphosphoric acid (PPA)modified asphalt, polymer modified asphalt and polymer mixed PPA modified asphalt at different temperature were comprehensively studied. The results show that the PPA additive can improve performances of matrix asphalt and polymer modified asphalt at the high and low temperature. The modification mechanism had more different performance between PPA and SBS modified asphalt at high temperature, and PPA using can significantly increase the viscosity of asphalt, and PPA has less influence on the elastic deformation recovery ability of asphalt, but SBS can greatly improve the elastic recovery of asphalt. The modification mechanism of PPA modified asphalt was analyzed by nuclear magnetic resonance (NMR) test, and the results show grafting, phosphating and cyclization reactions are happened between asphalt and PPA, which changes the carbon chain structure and chemical structure of asphalt, and asphalt become more viscosity.

Abstract:The mechanical properties of the boron steel used for automobile actually depend on the phase ratio of the microstructure, and the phase ratio is determined by soaking temperature and time. To obtain the expected phase ratio, it is needed to study the relationship between the experimental parameters and the phase ratio. The phase ratio of the material with different soaking temperature is studied with the cooling rate of 30 ℃?s-1, and the key parameters and method of controlling phase ratio combined with the empirical formula are given. It could provide theoretical reference to obtain the microstructure of provisions phase ratio in practical engineering.

Abstract:The synthetic fibers, with three lengths of 4.7,5.6 and 6.5cm respectively and each dosage of them was 5 kg?m-3, were used for the preparation of grade C40 concrete. Weber consistency, compressive strength and the toughness of concrete samples, including square boards, circular plates, beams and coped beams, were tested to analyses the effect of synthetic fibers on the mechanical proportion of fiber reinforced concrete, comparing with that of concrete with the equal volume (40 kg?m-3) of steel fibers. The results indicated that the addition of synthetic fibers lead to both decreases of flowability and compressive strength, and reduced the bending strength of concrete beam, and the longer the length of synthetic fibers, the lower the compressive strength of concrete. The synthetic fibers affected little initial rupture strength of concrete square boards or circular plate. The synthetic fibers can enhance fracture energy of concrete obviously and this action is higher than the same volume content of steel fibers. The synthetic fiber with length of 5.6 cm impressed the most of fracture energy of concrete. The stress and the deflection curve of synthetic fiber reinforced concrete displayed a “platform” structure in the process of its decline. Although the platform height was less than that of the steel fiber reinforced concrete, its length was longer obviously. It is due to the material characteristics of the structure of synthetic fibers.

Abstract:To reduce the congestion or wasted space caused by neglected space of buffer, the collaborative optimization of buffer allocation problem and facility layout problem was presented. Based on continuoustime Markov stochastic process theory, a queuing network node state model was established to solve utilization rate of facilities. A collaborative optimization model was built considering the utilization rate of facilities, material handling distance and floor area. The collaborative optimization model was calculated using improved NSGAⅡ. A case study of diesel engine cylinder block processing line was provided to prove the effectiveness of the proposed method.

Abstract:To solve line balancing problems for flexible machining line, a method was proposed, which can provide optimal stations configuration and operations assignment and sequence. After analyzing precedence constraint, clustering constraint and station constraint decided by machine capability, setups and workpiece orientation, a mathematical model was constructed, in which three objectives were considered simultaneously: number of machines, cycle time, line balancing rate. The multiobjective genetic algorithm (MOGA) was presented. A heuristic population generation and a heuristic decoder were designed. The Pareto ranking method and the sharing function method were employed to evaluate the individuals’ fitness, which guaranteed the dispersity and uniformity of the solutions. A case study for cylinder block machining line was carried out, and multiple optimal solutions were obtained by the MOGA. The computational results demonstrate the feasibility and effectiveness of the proposed algorithm.

Abstract:In order to research chaotic dynamics of electric vehicles, the vehicle experiment was carried out, and the experimental data were analysed. First, the vehicle experiment in the paving road was carried out, the vertical acceleration signals of wheel center, shock absorber top mount and battery bottom center were measured. Secondly, the noise of signals were reduced by using the wavelet analysis, and compare the effect between global threshold noise reduction and layered threshold noise reduction, then found that the effect of the layered threshold was better. With the denoised signals, the Poincaré sections and phase diagrams of the vertical of left front wheel center, the front left shock absorber top mount and battery bottom center were calculated, and time delay was calculated by using the mutual information method, and also minimum embedding dimension was calculated through the Cao method, the largest Lyapunov exponent was obtained by using the small data sets method. The results show that the presence of chaotic motions in the electric vehicle when traveling on paving road. The results of the study can avoid the generation of chaotic motion in the design and analysis of electric vehicle as much as possible.

Abstract:In view of the strong coupling between air mass flow and back pressure in the air supply system of high pressure proton exchange membrane fuel cell (PEMFC), a robust decoupling controller that combined the principal of internal model control (IMC) with multiple variable decouple control theory is proposed. The simulation results show that the internal modeldecoupling controller can not only provide a nice decoupling, but also get a much better robust performance compared with the traditional proportionintegralderivative (PID) decoupling controller when the real system does not match well with the nominal model; moreover, the proposed controller is also featured with less controller parameters and easy to be tuned.

Abstract:The effects of variable geometry turbine(VGT)/ exhaust gas recirculation (EGR) on pressure ratio, airfuel ratio, specific fuel consumption, and emissions of NOx, CO, HC, CO2 and smoke from a heavy duty diesel engine have been investigated. The results show that pressure ratio and airfuel ratio decrease, and fuel economy deteriorates with the increase of the opening of the EGR valve. NOx emission can be strongly affected by the opening of the EGR valve and VGT valve. NOx emission can be greatly reduced by increasing the opening of the EGR valve and VGT valve, and there is good logarithmic relationship between decline of volume concentration of NOx and the opening of EGR valve. However, HC, CO, CO2 and smoke emissions are increased. In order to lower NOx emission, while effectively controlling fuel economy and smoke emission, 50% of the opening of the EGR valve combined with 45% of the opening of the VGT valve is suitable at medium load, and 75% of the opening of the EGR valve combined with 55% of the opening of the VGT valve is suitable at high load.

Abstract:A new solarinduced ventilation wall with grille induced channel, which utilize solar energy and wind energy to cause indoor natural ventilation, was proposed. The effects of structural parameters on the ventilation performance of the new structure were studied at different outdoor wind speed and solar radiation intensity by threedimensional computational fluid dynamics method. The results showed that the builtin grille induced channel can utilize the induction of outdoor wind in formation of main channel of solarinduced ventilation wall to strengthen natural ventilation. The mass flow rate of the new solarinduced ventilation wall firstly increases, and then decreases with the increase of the ratio of grille spacing to grille height, there is an optimum ratio for the maximum of mass flow rate. With the increase of the ratio of wind induced channel width to main channel width, the mass flow rate of the solarinduced ventilation wall under different outdoor wind speed firstly increases and then decreases.

Abstract:In order to improve the efficiency of regression testing, test case prioritization technology is particularly important. This paper is mainly to identify possible path segments by the call graph between components, to calculate path segments’ cover index by the execution history of test cases, and finally to put forward a priority model of test case based on the sort of the cover index.Through the research of this model, it can effectively carry out regression test, and detect the errors in the program timely.

Abstract:Maxmin Ant System is a kind of heuristic algorithm with excellent performance, which is commonly used to solve combinatorial optimization problems. But it costs a long time when scale of the target problem is large as well as iterations are a lot. The experiment took the open source packet ACOTSP as a reference, used the advantage of multithreaded GPU, and implemented ACO algorithm on CPUGPU platform by parallel ants strategy. While the parallel algorithm is running on GPU, we also analyzed the impact factors carefully, such as data transmission, memory hierarchy, library calls et al, and made useful optimization. Eventually, the experiment made 13 times speedup, proving the parallel strategy is highly efficient and applicable.

Abstract:Megaprojects organization innovation mode was the implementation of construction strategy should consider the issue. At first, the evolvement of management mode of construction megaprojects organization was discussed in China since 1950s. Secondly, the management model of the Hong KongZhuhaiMacao Bridge project, the Three Gorges Project (TGP), the National Stadium (Bird’s Nest) project and the expo axis project was identified by comparative analyze. Then, from the perspective of trigame’s rule model, the equilibrium solution of the game was discussed so as to find the optimal strategy. Furthermore, it gives advices and recommendations to how to develop the supervision system of the construction megaprojects under management model in China.

Abstract:To effectively solve the problem of pricing strategies in dualchannel supply chain with heterogeneous product, the effect of product dissimilitude on pricing strategies was researched. Firstly, a pricing decision model of dualchannel heterogeneous product supply chain was built based on consumer surplus theory. Then Stackelberg game was applied to get the optimal pricing and profits of manufacture and retailer. Finally, the effect of product dissimilitude on pricing strategies and profits of manufacture, retailer and the whole supply chain was analyzed by numerical experiment. The results indicate that strategy of highend product dissimilitude is benefit for manufacture, retailer and the whole supply chain.