Abstract:An adaptive auxiliary domain method that combines the Metropolis algorithm and the support vector machine (SVM) method is proposed in this paper. First, conditional sample points were generated in the target failure domain by using the Metropolis algorithm and then an SVM model with the candidate points produced in this process was trained. Secondly, according to the SVM model obtained, a number of extra sample points were adaptively added into the training set and the SVM model was updated until the stopping criterion was reached. Then, the final SVM model was taken as an auxiliary failure domain and the corresponding approximate failure probability and two conditional failure probabilities were calculated respectively. Finally, the approximate failure probability was corrected with the two conditional failure probabilities to make the final target failure probability asymptotically unbiased and more stable. The examples given in this paper demonstrate the satisfactory accuracy, efficiency and robustness of the proposed method.

Abstract:Computational fluid dynamics and experimental methods are utilized to study the flutter characteristic and countermeasure mechanism of opencrosssection. The wind tunnel test results show that the prototype section of one suspension bridge tends to suffer flutter instability at relatively low wind speeds. The flutter critical wind speed is obtained by using the CFD approach, which conforms well with wind tunnel test results. Numerical simulations show that vortex shedding and drift from the lower surface of the section at high wind speeds match with the torsional displacement of the deck section. Vortex drifting produces the same direction aerodynamic torque as the section movement direction, leading to a flutter divergence. The same calculation is done with three sections added with different types of stabilization plates. The existence of stabilization plate prohibits the development and movement of main vortices, resulting in aerodynamic forces acting on the girder related less to displacement, thus suppress the flutter. Sectional and aerodynamics model wind tunnel tests are conducted to prove the effectiveness of stabilization plates. The results show that the lower stability plate is an effective vibration suppression measure for the flutter of the opencrosssection.

Abstract:Based on the conventional high strength bolt connection, a new occlusive high strength bolt shear connection was developed. Shear bearing capacity experiment of 4 conventional high strength bolt connections and 14 occlusive high strength bolt connections was conducted. The experimental process and the collapse phenomena were introduced and described in detail. It is found that the failure mode of occlusive high strength bolt connection is mainly the dislocation of plates. Grooving on plates could effectively increase the loadbearing capacity of the connection. Moreover, the capacity of the connection increases as the bolt pretension and the depth of grooves increase. A finite element model (FEM) was established, and the failure mode and the loaddeformation curves of the connection was simulated. It is indicated that the FEM is effective because of good agreements between the results of the experiment and that of numerical model. Thus, it is believed that the established FEM could be used to execute the subsequent numerical analyses.

Abstract:The threedimensional vertical column system and the multiyield surface plasticity constitutive model were implemented for the problem of nonlinear seismic site response to bidirectional horizontal earthquake loading. The practical issue concerned the specification of the accuracy and efficiency of site response analysis. The crucial parameters describing the multiyield surfaces, soil thickness division and boundary conditions, and frequencies or modes for the damping formulation could help preforming the accurate nonlinear seismic ground response in the bidirectional earthquake. The layered soil column was divided into multiple subsoils with different viscous damping matrixes according to the shear velocities as the soil properties were significantly different. The accuracy of the threedimensional soil column method was verified by the dynamic centrifuge model test results. It is concluded that the threedimensional vertical column model can be used for bidirectional nonlinear seismic local ground response analysis.

Abstract:In order to reveal the water transport characteristics of nonequilibrium flow on soil column with macropore under heavy rainfall condition, the influence law of the factors(i.e., rainfall intensity, duration time, initial water content, the equivalent diffusion distance between two domain, empirical parameter) on the seepage mechanism of nonequilibrium flow were analyzed by using the dual porosity model and the kinematic wave model. The results indicate that the larger peak and smaller depth range of water exchange calculated by dual porosity are larger than those calculated by using the kinematic wave model. The dual porosity model is more suitable for simulating water change of upper soil while the kinematic wave model is more suitable for simulating water change of bottom soil. The volumetric water content calculated by using the two models along the depth presents the characteristics of double knees. The depth of water exchange and wetting front will increase with the increases of rainfall intensity and duration time. With the initial water content gradually approaching to saturation water content, the wetting front moves down and the depth range of water exchange increases, but the peak of water exchange decreases quickly. With the equivalent diffusion distance increaseing, the water exchange rate significantly reduces, resulting in the nonequilibrium flow. There is a little change in wetting front, water exchange rate and water content of the matrix domain when the equivalent diffusion distance between two domains is longer than 5 cm. With the increase of empirical parameters (rw and n*), the wetting front moves down, but the water exchange rate increases. When the rw is more than 0.4 or n* is more than 2.5, the wetting front decline rate, the moisture content of soil’s profile, and the speed and variation range of water exchange slow down obviously, resulting in the lower risk of nonequilibrium flow.

Abstract:The effect of grouting on tunnel leakage was studied in terms of the leakageinduced settlements of ground and tunnel, and the convergence and internal forces of tunnel, using FEM simulation. Based on the numerical results, a dimensionless parameter R integrating the permeability and geometry of grouting and tunnel lining was suggested to study the effect of grouting. Using this parameter, the effect of grouting on tunnel leakage can be predicted. Moreover, the permeability state of fully impermeable, infinite permeable and fully permeable could be defined in terms of the values of R. The numerical simulation indicates that the leakageinduced internal forces is negligible and may not affect the tunnel safety from the point of view of tunnel bearing capacity

Abstract:Based on the phaseshift laser ranging principle, a smart tunnel laser convergence gauge was developed which consisted of a main engine, an adjusting device and the postprocessing software. The main engine has the functions of measurement, editing, calculation, and data transmission with enough memory to store monitoring data, and can encrypt the monitoring data to prevent data fraud. The adjusting device can be installed and disassembled quickly and easily. It can adjust the laser point to aim at the target accurately. Postprocessing software can process the encrypted monitoring data, draw convergencetime curve and generate reports automatically. The laboratory and tunnel onsite precision tests indicate that its monitoring precision can reach 0.50 to 0.68 mm when the length of the tunnel convergence line is within the range of 5.0 to 14.0 m. Compared with traditional convergence gauges and total stations, the smart tunnel laser convergence gauge has the advantages of high efficiency, low labor intensity and easy operation.

Abstract:A 2DH hydrodynamic and sediment transport numerical model was established based on Delft3D. The validated model was applied to study the cultivated impact of the construction of harbor projects on the characteristics of hydrodynamics and sediment dynamics in the southwest of Bohai Bay and their interaction between Huanghua Harbor and Binzhou Harbor for nearly 20 years. The results indicate that the construction of harbor projects gradually divides the southwest of Bohai Bay into 3 independent regions. Under the wavecurrent interaction, the distributions of suspended sediment concentrations (SSC) over a tidal circle are similar to the ones under pure current, but the magnitude increases eight times. The contour of SSC is parallel to the coastline on account of the enhancement of alongshore current while the proportion of nearshore SSC in the west of Huanghua Harbor, middle of Huanghua Harbor and Binzhou Harbor and east of Binzhou Harbor is redistributed on account of the increase of sediment load during flood. Overall, after the construction harbor projects, the southwest part of Bohai Bay gradually reaches its new equilibrium of sediment transport. The project of Huanghua and Binzhou Harbor in 2012 and their planning project in 2020 can reduce the impact of sediment transport between harbors in normal weather and normal wave weather, respectively.

Abstract:Considering the fact that the present roughness evaluation criterion of airport pavement still uses that of highway, this paper presented the comprehensive analysis of the roughness evaluation of airport pavement and road surface. By building kinetic models of aircraft and car, and taking vertical acceleration response of aircraft and car as evaluation index, a simulation analysis process based on Matlab/Simulink was conducted. Taking the representive aircraft and car as test subjects, this paper examined the differences in vertical acceleration response on rough pavement excitation, and analyzed the influence of speed, composition structure, front and rear track, quality distribution coefficient, vibrating element, quality and moment of inertia on the dynamic response of car and aircraft. Finally, according to the Boing taxi fatigue life criteria, the criteria value of IRI and the biggest gap under 3 m straight edge for the roughness evaluation of airport pavement were backcalculated respectively, investigating the important decision parameters for airport pavement management.

Abstract:The discrete element method (DEM) models were established by using twodimensional particle flow code (PFC2D) to simulate the fine sand compaction process, and the influencing factors, including compaction method, static force and vibrating compaction number, were investigated by using DEM and validated by field experiments. It is shown that the compaction of fine sand can result in the densification of particles and the horizontal orientation of long axis. For static compactions, the difference of densification effect in depth and the rotation of long axis are comparatively insignificant. For vibrating compactions, the decreases of porosity in the upper sands are more pronounced, and the number of particles with horizontal angle of deviation less than 30° increases by 33%. The increase in the number of vibration compaction can lead to the decrease in the porosity of the upper sands, however, it is not effective after fifth vibrating compaction. The simulation results are in good agreement with the experimental results, which verifies the feasibility and effectiveness of PFC.

Abstract:This paper analyzed temporary characteristics of parking occupancy rate (POR) at three different types of parking lots, i.e., shopping mall, office building and stadium, and evaluated the applicability of autoregressive integrated moving average method(ARIMA), Kalman filter and BP neural networks on the prediction of POR, based on parking lot detection data at Wujiaochang District, Shanghai. The results show that ARIMA and BP neural networks can achieve higher prediction accuracies as compared with the Kalman filter method, and the BP neural networks performs best for the shortterm prediction of shopping mall and office building. The prediction accuracy of the three methods decreases as the forecasting time step increases. Different prediction accuracies exist for different types of parking lots, and the prediction accuracy for weekdays is higher than that for weekends. And the model has good adaptability. This paper can provide reference for the selection of prediction methods for different types of parking lots.

Abstract:As the upgraded system of traditional cruise control, the adaptive cruise control (ACC) system can improve the driving comfort and safety. The development stages of ACC system were explicated in this paper. The latest research achievements of ACC system in recent years were discussed in detail from the aspects of environmental perception, tracking behavior of driver, vehicle dynamic modeling, ACC system control algorithm, and function extension of ACC. Based on these achievements, the common problems of ACC were summarized and some viewpoints on the trend of the future developments were given.

Abstract:The general characteristics of driver emergency steering lane change behaviors based on the China naturalistic driving data were proposed in this paper. The emergency steering characteristic was analyzed respectively in collision avoidance, lateral movement and steering stabilization phases, focusing on the steering duration time, the relationship between steering wheel rate and steering wheel deflection. The steering behaviors in three phases were described by using the steering primitive fitting by Gaussian function. The research results show that the steering primitive represents the general characteristics of driver steering behaviors. A linear relationship was found between the maximum steering wheel rate and the steering wheel deflection, and the steering time for a single steering primitive is constant. The driver emergency steering behaviors follow the characteristics of the reaching behavior. The driving emergency steering lane change is composed of steering primitives, while the single steering primitive is an opencontrol model, which indicates that the steering angle is predetermined using the maximum steering wheel rate.

Abstract:The handling performance of a 8×8 skid steered all terrain vehicle equipped with doublestream hydromechanical transmission(HMT) was studied. A 2 DOF dynamic model was proposed and verified by simulation and experiment. The result shows that there are great differences between the steady state performance of skid steered vehicle and Ackermann steered vehicle. The skid steered vehicle has a better transient handling performance because of the special steering mode. Moreover, the transit performance of the skid steered vehicle is better than that of the Ackermann steered vehicle. Furthermore, because of larger side slip angle during a turning, tyres of skid steering vehicle are more easily worn out.

Abstract:This paper analyzes the resolver angle error, and introduces the rotor angle observer to reduce angle ripple and the internal mode control algorithm to reduce phase current ripple of the big reluctance torque motor. Using this method, a certain PHEV project in United Automotive Electronic Systems Cooperation was studied. It is found that the motor control current ripple is decreased by 77%, and the torque ripple is reduced by 83% at 4 000 r?min-1, 100 N?m.

Abstract:The end plate of fuel cell stack with a metal bipolar plate is easily deformed under assembly pressure.A novel designed structure of the end plate was presented and its parameters was optimized by the numerical simulation based on the finite element method. A structural mechanics analysis model for the end plate was created by Ansys Apdl program and the Ansys Workbench software, and the size and shape optimization algorithm was introduced. The higher uniformity among steel bands force, less weight of end plate, and lower deviation of the fixed bolt axis are objective functions. The influence of the variable size and shape dimensions on the above objective functions was analyzed, aiming to determine the optimized size and shape of end plate, and improve the contact pressure uniformity between the components and the stress behavior of the steel banding. A 2D quarter stack model which has 11 layers to compare the contact pressure uniformity between bipolar plate and MEA(membrane electrode assembly).

Abstract:An experimental study on the fuel injection strategy for low compression ratio diesel engine at different altitudes was conducted. Tests were conducted on a midspeed heavyduty intercooledturbocharged diesel 14.25∶1 CR (compression ratio) engine whose intake and exhaust pressure was controlled by the Plateau simulation test system to stimulate the altitude conditions including 0, 1 000, 2 000, 3 000， 3 750 and 4 500 m. The results indicate that the time of cranking period is increased with the altitude, the rising ratio of speed of startup period is reduced, the time and undershoot speed of after start period is increased, and the starting performance is deteriorated. Besides, under the conditions of high altitude, the starting performance is more significantly effected by altitude, at an altitude of 2 000 m and below, the time of startup period and after start period is reduced by an average of 1.10 and 1.47 s for every increase in altitude of 1 000 m. At an altitude of 3 000 m and above, the time of startup period and after start period is reduced by an average of 18.48 s, 2.75 s for every increase in altitude of 1 000 m. On the plain, the increase of fuel advance angle, the starting performance is deteriorated, the time of cranking period is increased and the rising ratio of the speed of startup period is reduced, and the time of startup period and after start period is increased. Different total fuel mass injection strategies has little influence on the cold start process on the plain. At an altitude of 4 500 m, the appropriate increase of the fuel supply advance angle and the appropriate reduction of the total fuel mass injection could improve the starting performance. Too large an amount of total fuel mass may lead to the fluctuation in startup period, and the starting stability is deteriorated, however, too small amount of total fuel mass may prolong the time of cranking period and startup period.

Abstract:In view of the freeze due to the uneven heat transfer of the fourrowtube direct aircooled condenser, the idea of using variable diameter finnedtube bundles was put forward. Using the method of computational fluid dynamics (CFD), the numerical simulation of heat transfer characteristics of a variable diameter finnedtube bundles was conducted. It is found that the comprehensive performance and heat transfer uniformity of variable diameter finnedtube bundles are improved compared with the equivalent diameter finnedtube bundles. At the same time, in order to improve the poor thermal performance of this type of heat exchanger, the condenser performance increases but heat transfer uniformity does not change significantly when finnedtube bundles changes from nearly equilateral arrangement to nearly isokinetic arrangement. Moreover, the comprehensive performance of aircooled condenser is further improved and the sensitivity of heat transfer uniformity to Reynolds number changes after the addition of vortex generator.

Abstract:An acoustic propagation model of jetflow was deduced by geometrical acoustics based on the fanshaped stratified velocity model of shear layer built by CFD. Taken an actual openjet wind tunnel as research objects, the velocity characteristics of jetflow were given by numericalsimulation. A fanshaped stratified velocity model of shear layer whose speed changed uniformly with the angle, was built. The acoustic propagation between different velocity layers was deduced by using the sound refraction theory. The acoustic propagation model of jetflow was verified by aeroacoustic wind tunnel experiment which took sound source drift as the index. The results show that this acoustic propagation model is more accurate to predict sound drift. In conditions that jet flow velocity is high and shear layer thickness is large, the improvment is particularly evident.

Abstract:For given graphs G and H, Ramsey number R(G,H) is the smallest positive integer N such that any red/blue edgecoloring of KN contains either a red copy of G or a blue copy of H. Denote by G+H the graph obtained from disjoint G and H by adding edges connecting G and H completely. Let Bm=K2+mK1 and Fn=K1+nK2. It is shown that R(Bm,Fn)=4n+1 for n≥max{2,3m-2}； and R(F2,K2,n)=2n+3 for n≥38.

Abstract:In order to reduce the risks of F2F（farm to family）companies, an approach was proposed which combined failure mode and effects analysis with cloud model. Through the evaluation from a group of experts, the potential risks can be sorted based on the theories of fuzzy logic and probability. Besides, the risks and solutions were outlined by a case study.

Abstract:From the perspective of supply chain, this paper takes into consideration the production characteristics in ore blending process, and establishes a 01 mixedinteger program which aims at maximizing the profit and minimizing the deviation of product’s ore grade, and satisfies the constraints of production capacity, resource limits, inventory balancing and product quality requirements. The Lagrangian relaxation algorithm (LR) is adopted to solve the problem. Computational experiments show that LR could fast obtain the feasible solution for mediumscale instances, and could obtain the optimal solutions within reasonable time for largescale instances while CPLEX fails to obtain the feasible solutions. Besides, the sensitivity analysis on the grade parameters is conducted, and the results show that disturbance of the grade is a sensitive factor for the quality deviation and the general objective function value.