Abstract:The pantograph of high-speed train is one of the main sources of aerodynamic drag and noise. To explore the method for reducing noise and drag of the pantograph in the high-speed train, the whorl structure of pantograph rods was designed based on bionics, and the influence under the parameters of pitch and diameter of the thread on noise and drag was studied. The typical size of pantograph rods was selected to establish fluid simulation analysis model. Furthermore, based on unstructured hybrid grid, the Standard k-εturbulence model and the broadband noise model were both used to calculate the flow field distributions and the values of aerodynamic noise and drag. The results show that the pantograph rods with whorls structure can better influence the formation of cylinder wake vortex zone, which is the main reason for reducing aerodynamic noise and drag effectively. In order to further explore the pantograph rods with whorl surfaces, two different types of whorl structure were designed, including grooved thread rods and convex thread rods. And the flow field calculation results were analyzed under different pitch and thread diameter parameters respectively. The results demonstrate that the drag reduction and noise reduction effect of convex threaded members is better than that of the grooved ones, when the parameters of pitch and thread diameter are fixed and the wind speed is at 350 km/h. Besides, the grooved thread rod with pitch PPD=60 mm and the diameter d=1 mm can achieve obvious effect of drag and noise, and the drag reduction rate of only single rod reaches 3%. However, for the type of grooved thread rod, the ratio of the thread diameter and cylinder diameter d/D is in the range of 0.017~0.067 when the pitch PPD is fixed. With the increase of thread diameter d, the aerodynamic noise and drag both increase, while the aerodynamic noise and drag decrease significantly when the value of d/D exceeds 0.067.

Abstract:Head checks (HCs) at rail gauge corner and shoulder were inspected by X-ray computed tomography scan technology (CT scanning). The boundary points at the mouth and tip of the real HCs were obtained by grid method to establish the numerical model of the real HCs. Taking the HCs at the gauge corner and shoulder of the high rail in a heavy-haul railway sharp curve with traffic gross tonnage of about 62 MGT as an example, this study analyzed the transformation of the stress intensity factors (SIF) at the tips of multiple HCs and the effect of the crack number on them. The results show that the HCs are more likely to extend with an orientation of 10°- 30° with respect to rail longitudinal direction， always less than 0 under any condition, indicating that the crack is not extended by Model I (opening). HCs are greater than 0, and the trend of is reduced from positive to negative along rail gauge corner to crown when contact patches pass by the crack central mouth, which shows that the HCs is mainly composed of Model II (sliding) and III (tearing). The existence of multiple HCs will promote their propagating as Model II and III, and the influence will be enhanced with the increase of crack number. Compared with the single crack, SIFs at the tips of multiple cracks will increase, and the SIFs at the tip of the middle crack will be greatly influenced by adjacent cracks. Therefore, at least 3 cracks are recommended in crack propagation modeling for crack prediction.

Abstract:In order to analyze the dynamic response of deck pavement in the process of rotating opening of bascule bridge, taking the Tianjin Xiangluowan Haihe Bridge as the research object, this study established a 1/4 fine finite element model of bascule bridge including the rotating shaft. The dynamic simulation of the variable speed opening process of the bascule bridge was carried out, and the dynamic responses of steel bridge deck pavement system at different opening angles and different opening speeds were tracked. The results were compared with the analysis results of the simplified bascule bridge model. which show that the stress concentration of interlaminar shear stress of pavement occurs both in transverse and longitudinal directions during variable speed opening. The tensile stress and interlaminar shear stress of pavement increase with the increase of the opening angle, and reach the maximum at the maximum opening angle. The longitudinal position of the peak is the free end of the structure, and the dynamic stress response of a refined rotating shaft model during its opening is 15% ~20% larger than that of a simplified rotating shaft model. Therefore, it is suggested that the refined rotating shaft model should be adopted in the composite structure of the open bridge pavement system at the design stage.

Abstract:In order to study the relationship between the driving trajectory and speed of small vehicles under natural driving conditions and risky road sections of mountainous roads, the four one-way curves of Fuzhou Forest Park passing through the Tunxi-Guling scenic section are taken as the research object. The UAV is used to capture the video data of the whole natural driving process of small vehicles from entering to leaving the curve, and the tracking motion module of the Ae software is used to track the trajectory of the left front wheel of the vehicle and calculate the vehicle turning speed. The length of each curve risk section is obtained according to the driving trajectory and speed. The results show that the risk section of Curve 1 is 0~2.273 m and 32.838~ 39.268 m, the risk section of Curve 2 is 43.375~46.039 m, the risk section of Curve 3 is 21.001~21.507 m, and the risk section of Curve 4 is 18.521~24.283 m. In this study, the two actual driving data of vehicle trajectory and driving speed are used as the entry point, which provides a method based on the natural driving state of small vehicles for the identification of risky road sections in mountainous areas.

Abstract:Shield tunnel of Shaoxing Metro Line 1 has the design features of large diameter and thick section. Considering the different sections of elastic rubber and composite rubber gasket, the single -row -hole, multi-row-hole and composite types of gaskets are designed. The applicable optimal waterproofing scheme is obtained by finite element analysis, “one” seam water pressure resistance test and compression test. The FEM results show that the maximum contact stress and average contact stress of the single-row hole gasket are the largest, which indicates that its water-proof ability is better. The water resistance test results suggest that the water pressure resistance decreases with the increase of joint opening, and the waterproof capacity of the single-row hole gasket is optimal. The compression test results show that the compression force of the gasket increases slowly first and then increases rapidly, and the assembling of the single-row-hole and the composite gasket is easier. According to the numerical simulation results and test results, single-row-hole type elastic rubber gasket is selected as the joint waterproofing scheme.

Abstract:Aiming at the problem of insufficient research on deformation characteristics of cement mixing piles composite foundation under subgrade filling at present, based on a construction case of railway subgrade filling reinforced by cement mixing piles in marine soft soil areas of China, this study monitored the deformation of composite foundation for cement mixing piles during subgrade filling. The deformation characteristics of composite foundation of cement mixing piles under subgrade filling were analyzed, and suggestions for subgrade filling rate control and cement mixing piles reinforcement scheme design were provided. The results show that the compression of the foundation reinforcement zone accounts for 56.1% of the total settlement under subgrade filling, and the maximum settlement rate is 2.4 mm/d. The lateral deformation of plain fill and silt layer is significant, and the maximum lateral deformation rate is 4.6 mm/d. The strata within 7 m from the foot of subgrade slope and above the depth of 5 m are greatly disturbed by the construction of subgrade filling. The lateral deformation rate of the slope is closer to the control index than the settlement rate of the foundation and the subgrade filling rate should be controlled mainly by controlling the lateral deformation rate of the slope. In this construction case, the cement mixing piles reinforcement scheme can meet the control requirements for post-construction settlement of subgrade of all railway types, the design of cement mixing piles in similar projects mainly controls the influence of subgrade filling construction on adjacent structures.

Abstract:Based on the interaction mechanism of harmonious development of new rural economy, transportation and rural ecological environment, the paper introduces coupling and coordination evaluation system and analyzes the coupling harmonious development of new rural economy, transportation and rural ecological environment in Yunnan province from 2007 to 2016 by using coupling harmonious degree model. The results show that the comprehensive development level of these three systems is in the trend of increasing, while the rural ecological environment comprehensive evaluation index fluctuates greatly, and presents the undulation of rising first, and then falling and rising again. In recent years, the degree of coupling coordination shows a steady upward trend. As a whole, the three systems have realized the change of improvement from slight imbalance recession to primary coupling coordination. However, the coupling coordination relationship of new rural economy-transportation-rural ecological environment is in a state of rivalry, and coupling coordination level is still relatively low. The development of rural ecological environment system lags behind, becoming the obstacle to the improvement of the level of coupling coordination among the three systems. Finally, this paper proposes corresponding suggestions.

Abstract:At present, there are a series of problems in the optimization algorithm of train energy-saving control, such as the unobvious effect of optimization and the slow convergence speed. A PSO algorithm with adaptive inertia weight and learning factor with adjustable ability and improved speed update formula is proposed. Firstly, inertia weight is used to balance the search ability in different stages, and dynamic learning factor with adjustable ability is added to enhance the operation efficiency and convergence ability of the algorithm in the later stage. Meanwhile, penalty function is introduced to transform the constraints in train operation into penalty factors, which can improve the search rate. Then, the traditional velocity updating formula is improved to reduce the probability of selecting unsatisfactory particles for the optimization results. After simulation and analysis by Matlab, compared with the traditional train operation optimization algorithm, the improved optimization algorithm converges faster and has better energy-saving effect.

Abstract:Transportation plays a key role in regional economic development, which facilitates the communication and exchange between people, people and cities, cities and cities, and affects the development, transformation and upgrading of regional economy. Due to its advantages of fast speed, convenience, safety and comfort, the high -speed railway has a significant impact on the regional economy. For large and extra -large cities, high-speed railways help optimize the urban industrial structure, balance regional economic development, and drive economic growth, which aids cities to develop radiation effects with their local characteristic economy and regional advantages. For small and medium-sized cities, high-speed railway may bring some negative effects such as the siphon effect. Through the classification and analysis of the opinions and achievements from various documents, this paper summarizes the impacts of high-speed railway on regional economic development in terms of ecological economy, regional accessibility, regional industry and regional effects.

Abstract:The Air Traffic Control (ATC) decision updates along with the convective weather conditions in real time. In the absence of decision-making support tools, the different rerouting preferences of the pilots deepen the controller workload in convective weather. In response to the convective weather covering the planned route in tactical stage, the Weather Avoidance Field (WAF) product considering the pilot's actual flight preference was used to accurately reflect the impact of convective weather during actual flight. Based on the continuously updated Weather Avoidance Field products, a multi-objective integer programming model was established and a genetic algorithm based on linear combination weighting was designed. Taking the city-pair -- Guangzhou Baiyun to Shanghai Hongqiao-- as an example, this study finds out that the generated diversion route completely avoids the actual continuously updated convective weather, which can be used for the decision support of the controller in the tactical stage.

Abstract:In order to study the passenger traffic characteristics of check -in hall of airport terminal building, based on the actual situation of check-in hall of Terminal 2 in Nanjing Lukou Airport , this study divides the check-in hall into three areas of the entrance and exit area, the corridor area and the commercial area. The data of three parameters (flow, density and speed) of passenger traffic characteristics in each area collected by video recording method are analyzed, and then the relationship between three parameters is fit by function. The results show that the average speed of passengers in each area of the check-in hall is 0.801 , 1.089 and 1.188 , which are lower than the average speed of domestic and foreign passengers; the fitting relationship between passenger density and speed in each area is inversely linear, and the passenger speed decreases gradually with the increase of density; the fitting relationship between passenger density and flow is a quadratic parabola, and the passenger flow increases with the increase of density, first increases to the optimum passenger flow and then decreases until it reaches the blocking density. The results provide a basis for the airport to establish passenger flow early warning level and further plan and develop the commercial area.

Abstract:The rural road network scale prediction is one of the main contents of "Four-merit rural roads" planning. In view of the limitations for a single forecasting method, this paper proposes a combined forecasting method based on the theory of entropy weight, which reasonably allocates weight of the land coefficient method, the density of population and economic method, and connectivity method. Taking the rural road in Anji county as an example, it fits the rural road network scale and verifies the validity and rationality of the three single forecasting methods. Through three kinds of error indexes of absolute average error, absolute average percentage error and root mean square error, it constructs evaluation matrix, and respectively calculates the weight coefficients of the three single forecasting methods，namely 0.115 4，0.240 3 and 0.644 3，which verify that entropy weight method can distribute weight coefficients objectively. It shows that the combination forecasting method can reduce the forecasting risk of a single model, which predicts the rural road network scale in future years.

Abstract:A reasonable left -turn waiting area setting can greatly improve the capacity of the left -turn lane. Firstly, the conditions and effects of left-turn waiting area setting are explored under different traffic saturation of left-turn lanes. Secondly, the capacity model of left-turn lane is modified considering the factors such as the capacity of waiting area, change interval and the microscopic characteristics of the vehicles. Finally, the above modified model is verified by traffic survey and VISSIM simulation. The results show: 1) The left-turning waiting area channelization is beneficial to the improvement of the left-turn lane capacity, but with the increase of traffic saturation, the effect is smaller and the maximum queue length is larger; 2) Through VISSIM simulation, the error of the capacity model can be controlled below 2% considering the influence of factors such as the waiting area capacity.

Abstract:Interlaminar shear failure of steel bridge deck pavement is the main failure of pavement. The combined discrete-continuum model of steel bridge deck pavement composite structure was established to study the interlayer shear behavior of composite structure. The change law of interlaminar failure behavior of steel bridge deck pavement structure under the temperature of 30℃ and the influence of shear rate on the shear stress between steel bridge deck and pavement were analyzed. Research results show that too high or too low driving speed is disadvantageous to the steel bridge deck pavement. Compared with the calculation results of discrete element model, the discrete-continuum model is more reasonable.

Abstract:The fuel tank is an important part of the fuel supply system. Leakage due to the cracking of fuel tank during the operation may lead to dangerous accidents. In order to ensure the strength of the fuel tank in use, the finite element method is applied to analyze the structural strength of the fuel tank in the process of fuel tank design. Taking the braking process of the fuel tank with half tank fuel as an example, the deformation and stress of the fuel tank are calculated by finite element method, and the weak links of the fuel tank are found out, which is consistent with the actual use. Aiming at the weakness of the existing fuel tank, some suggestions for structural improvement are put forward. The finite element analysis results show that the improved scheme is effective and feasible.

Abstract:Taking the new TBM boots as the research object, the force transmission characteristics between the boots and other mechanisms are created according to the three-dimensional model of the test bench. The contact model between the boots and the surrounding rock in the double-support working mode is established, and the finite element method is used to study the support. The stress and displacement distribution of the contact surface between the boot and the surrounding rock shows that the comprehensive stress distribution of the support shoe and the surrounding rock is relatively uniform, and it is distributed within the range of in the circumferential dimension. The maximum stress on the contact surface is 13 MPa, and the maximum stress on the contact surface of the surrounding rock is 4.03 MPa. The comprehensive displacement of the contact surface of the support shoe is small in the middle and large at both ends, and the displacement at the contact surface of the surrounding rock is large, and the displacement to the periphery gradually decreases. The analysis results provide some reference for improving the stability of the whole machine.

Abstract:A building fire prediction and evacuation system based on cellular automata is proposed for densely populated large buildings. Firstly, the grid method is used to establish a planar model about the building, and the cellular automaton model is applied to realize the fire prediction and the crowd evacuation on the same interface. Then, the best exit design scheme for evacuating the crowd is obtained by changing different parameters of the exit. Finally, the improved ant colony algorithm is adopted to optimize the evacuation lights in the building, so that it can dynamically indicate the direction of escape. The simulation results show that the system can effectively solve the problem of exit design and personnel safety evacuation in the event of fire in the building group.

Abstract:The popular sensors used in land welding automation are faced with lot of difficulties while they are used in water. It is meaningful to find a new kind of sensor which is suitable for wet welding. Ultrasonic Phased Array(PA) can work in water conveniently, which controls each element to send out required sound beam separately and focus on specific points. Compared with single ultrasonic sensor, PA works fast and effectively. Interference principle of acoustic beam is analyzed at first, and then the relationship between focusing precision and the shape of PA, the number of sensor element, gap distance between adjacent units and time resolution is revealed with simulation. Then, proper physical parameters of PA are determined. Finally, high time -resolution circuit based on CPLD is given out, which works together with sound emitting and receiving circuits to realize fast scan on welding workpiece, so that the seam line could be deduced with underwater distance detection. Researches manifest that PA is effective for wet welding.

Abstract:In order to accurately and quantitatively obtain an industrial layout scheme of an irregular port-vicinity industrial zone, the harbor area and the target industrial land were divided into square grids of the same size by the grid method in this study. The relevancy degree between grids is determined by the known relevancy degree among industries, harbor areas and industries, and the irregular port-vicinity industry with the goal of maximizing the comprehensive relevancy degree among all grids isconstructed. Finally, an integer-coded multi-agent evolutionary algorithm is compiled based on grid number sorting to obtain the layout scheme with the greatest comprehensive correlation. Taking the Yancheng Binhai Port as an example, the coastal port industry is divided into 50 grids. According to the planned area, the grids occupied by six industries to be developed are determined. The multi-agent evolutionary algorithm is compiled by MATLAB. The agent grids are set to 20×20 to run 10 times for 150, 200 and 300 generations of evolutionary algebra, and three layout schemes with the greatest correlation degree are obtained. The comprehensive correlation degree is 549, 550.8 and 550 respectively. The best result of running 50 000 generations of genetic algorithm is only 520.8, which shows that the model and algorithm have strong superiority in solving the problem of irregular layout of port-vicinity industrial zones quantitatively.