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June 30,2013
Volume 6,Issue 12
Pages -
Subject Area:Aerospace Propulsion System,Bridge and Culvert Engineering

Title: Precise design of low-thrust phasing orbits with complex constraints

Authors: SHANG Haibin, WANG Shuai
PP: 1170-1176
Abstract: The precise design problems of low-thrust phasing orbits with complex constraints were studied. Firstly, the motion model of the spacecraft was built based on the modified equinoctial orbital elements. Then, the control law of the low-thrust engine was discretized and the time and the direction angle of the thrust on the pitch points were taken as the optimization parameters.The control law on the other points could be obtained with cubic spline interpolation. Thus, the orbit design was transformed into a multi-parameter optimization problem. Finally, the simulated annealing algorithm and the sequential quadratic programming were employed for solving the optimization problem to get the global optimal solution. The simulation experiments on phasing mission of global positioning system (GPS) satellite, sun synchronous satellite and geostationary satellite showed that the proposed approach can design low-thrust phasing orbits with complex constraints efficiently.
Keywords: aerospace system engineering; low-thrust; phasing orbit; orbit design; direct method

Title: Development of the ramjet inlet for air-breathing supersonic cruise missile

Authors: XIE Lvrong, GUO Rongwei
PP: 1163-1169
Abstract: The inlet types and layout on missile are reviewed in this paper. Combined with air-breathing supersonic cruise missile development, the design of the combniation ramjet with inlet will be incorporated in missile. At the same time, this design will meet the requirement of long-rang, stealth, wide flight range, maneuverability and all-purpose missile. High performance inlet with fixed-geometry, designed conventional inlet based on unconventional shape, selfstarted/restarted technology of inlet with fixed-geometry, designed variable geometry inlet and coupled poly-inlets etc are the key issues of ramjet inlet design. According to current position in our country, the advices of inlet foundation research are brought forward which include establishing database of the inlet performance, investigating realizable flow control, designing variable geometry inlet and unconventional inlet.
Keywords: aerospace propulsion system; supersonic cruise missile; review; inlet design; development; key issue

Title: Comparison analysis of child occupant injury based on multiple working conditions in vehicle front crash

Authors: ZHANG Junyuan, ZHANG Qiushi, LI Xingfu, CHEN Chao
PP: 1155-1162
Abstract: Due to the common vehicle seat belts, air bags and seats are designed for adults, child occupants in car collision accident casualty risk is far higher than adult occupants. Based on the computer simulation analysis method, the child occupant injury in multiple working conditions for vehicle front crash was obtained. Through a comparison analysis, the most serious condition types and the influence degrees of adult occupants in car were found. The above studies are benefit for the deep analysis of the causes of child occupant injury, and can guide subsequent child restraint system design.
Keywords: vehicle engineering; front crash; child occupant injury; computer simulation; comparison analysis

Title: New methods for characterizing fatigue properties of aging asphalt mixture

Authors: LV Songtao, CHEN Jie
PP: 1148-1154
Abstract: In order to characterize the fatigue properties of aging asphalt mixture, the actual aging degree of asphalt pavement was simulated by the different oven aging tests. The rule between strength and loading rate through strength tests under different loading rates was revealed. Based on the strength values under different loading rates, the asphalt mixture real stress ratios corresponding to the fatigue loading rates were obtained. The asphalt mixture fatigue equations were created based on nominal and real stress ratio through fatigue tests. The fatigue equation characterized by real stress ratio could be extended to the strength failure point, which the fatigue life was 1. Furthermore, the inner relationship between the strength and fatigue failure were unified. The fatigue equation of asphalt mixtures at different aging degree were established based on real stress ratio, and all the fatigue curves passed through the point of (1,1).
Keywords: road engineering; asphalt pavement; fatigue; aging; stress ratio

Title: Research on the stable behavior and effect parameters of the thin-walled and high-span continuous rigid frame bridge

Authors: GONG Yongzhi, XIA Wenmin, TANG Zhixiong
PP: 1141-1147
Abstract: In this paper, according to the bridge example of the Wen-ming super bridge, which is the thin-walled high pier and long-span continuous rigid frame bridge, the analysis model of 12# high pier building in this bridge was constructed using the shell element of MIADS software. During the process of analysis, the influence of the double nonlinear was considered, and its stability was analysed under different working conditions. At the same time, the effects of some parameters such as concrete strength, the wall thickness of high pier, the setting of straining beam on the stability of bridge were discussed. The results could provide valuable references for similar projects in the future.
Keywords: bridge and culvert engineering; thin-walled and high pier; continuous rigid frame; stable behavior; effect parameter

Title: Research on the effect of widened connection timing on force performance of continuous rigid frame bridge

Authors: WANG Hui, LIU Wei, SHI Xuefei
PP: 1136-1140
Abstract: Based on the widening project of construction prestressed concrete continuous rigid frame bridge, the effect of different connection timing on the force performance of widened bridge structure was studied using grillage model. The results showed that, with the connection time growth, whole bending moment diagram of old bridge presented a down trend, while that of new bridge presented an upward trend. Longitudinal stress of old bridge inclined to downwardness while that of new bridge showed a trend of increase. The force of the flange joint of new and old box girders showed a trend of decrease, and bearing reaction of old bridge showed a trend of decrease while new bridge showed the opposite, due to the effect of shrinkage and creep. The choice of connection timing had a great influence on the force performance of the bridge structure, therefore the time joining together should be comprehensively determined by structural behaviors and economic conditions.
Keywords: bridge and tunnel engineering; widening; connection timing; shrinkage and creep

Title: Analysis of influence factors on the propeller hydrodynamic performance

Authors: REN Xuanqi, WANG Chao, GUO Chunyu, WANG Guoliang
PP: 1129-1135
Abstract: In order to analyze the influence factors on the hydrodynamic performance of the propeller, the numerical simulation of open water propeller was made using computational fluid dynamics (CFD）software. The value of the propeller point was prepared by FORTRAN program, the propeller geometry was modeled by preprocessor ICEM and the local grid was refined. The numerical simulation method was used to take variable scale research on the main geometrical parameters which affected the performance of propeller. The various parameters which include propeller area ratio, pitch ratio and skewed on the performance of the propeller were analysized. The calculation results showed that the area ratio and pitch played an important role in the thrust performance of propeller, while the influence of skewed was relatively smaller.
Keywords: ship and ocean engineering; propeller; hydrodynamic performance; numerical simulation; pitch ratio; skew

Title: Main dimension optimization for scheme design of round-bilge craft

Authors: CHEN Keqiang, CUI Jingyu
PP: 1124-1128
Abstract: By multiple regression of the residual resistance of the round-bilge craft, this paper set up a fast method to predict the resistance of the round-bilge craft. For the scheme design stage with given displacement and speed, the main dimension including the length, breadth and draft of the craft were optimized by taking the resistance as the target, the hull coefficients, light ship weight and sea-keeping performance as the constraint conditions. This research provided a platform for the main dimension choose of the round-bilge craft scheme design.
Keywords: ship engineering; round-bilge craft; scheme design; main dimension optimization

Title: Study on thrown object’s kinetics of vehicle crash based on scatter characteristics

Authors: XU Hongguo, REN You, DU Xuejing, LIU Fuju
PP: 1119-1123
Abstract: Generalized kinetics model was developed to use vehicle crash formed scatters in the vehicle crash reconstruction. The collision scatter simulation tests were carried out at the same initial velocity of vehicle collision. Movements of the collision scatters after landing were consisted of elasticity, plasticity and the plastic. In test conditions, the similarities and differences of the kinetic characteristics for the material properties of the three kinds of collision scatters were analyzed, and the changes of the kinetic characteristics were involved in scatter throwing speed, height and the angle. Simulation tests showed that the effect of material properties of scatters on nonlinear trajectory of the vehicle collision scatter with throwing angle was evident. These results would provide the theoretical basis for analyzing traffic accidents.
Keywords: vehicle operation engineering; traffic accident; crash; scatter; kinematic modeling; simulation test

Title: Research on train interval control under moving block

Authors: ZHANG Youpeng, SUN Yongsheng, ZHAO Bin
PP: 1112-1118
Abstract: The algorithm of train interval control under moving block was studied. Interval is the key issue to affect the safe operation of trains, and controlling the train interval effectively can ensure the safe operation of trains under moving block condition and achieve the goal of improving line capacity. Therefore, train interval control algorithm for three interval patterns under moving block were designed to achieve train security tracking operation in “hit a hard wall” and “hit a soft wall” modes and ensure train safety operation. By comparing the simulation of algorithm under “hit a hard wall” and “hit a soft wall” instance, it was found that this algorithm could ensure the tracking train to stop out of the forward train rear protection points safely. At the same time, “hit a soft wall” mode could improve line operations efficiently.
Keywords: traffic information engineering and control; train interval; moving block; algorithm

Title: Study on coordinated control of mid-block pedestrian crossing buttoned signal and intersection signal

Authors: SHI Donghua, CHEN Xiaohong
PP: 1102-1111
Abstract: The pedestrian delay, motor vehicle delay, vehicle stops at mid-block buttoned signal pedestrian crossing and motor vehicle delay, vehicle stops intersection were analysized. From the point of coordinating signals control and improving traveler time effectiveness and environments, this paper established coordinated control optimization model between mid-block pedestrians crossing buttoned signal and intersection signal. The minimum delay and vehicle stops were taken as objective functions, offsets, pedestrian waiting time, green time and cycles were taken as decision variables, the control parameters were optimized using genetic algorithm (GA). Then, this model was proved to be effective using case analysis combined with Synchro software.
Keywords: traffic road; buttoned signal; signal coordinated control; multi-objective programming

Title: Characteristic analysis of Chinese railway freight car flow network

Authors: FAN Zhenping
PP: 1095-1101
Abstract: This paper took Chinese railway freight car flow network as background, used complex network theory to analyze the network characteristics, and measured the parameters of the degree, strength, the entropy of degree distribution, the entropy of strength distribution, the entropy of weight distribution, cluster coefficient, the rich club coefficient and assortativity coefficient of the car flow network. The results showed that the network average degree was 6.64, average strength was 1 087.43, strength and degree were positively correlated. The entropy of degree distribution, strength distribution and weight distribution were closed to the theoretical maximum, indicating that the train distribution, station car flow distribution and train car flow distribution were relatively balanced. Average cluster coefficients of topology and weight network structure were respective 0.488 and 0.491, suggesting rich club phenomenon was evident and the network was assortative mixed.
Keywords: rail traffic mangement; complex network; railway freight transportation; car flow network; network characteristics

Title: An empirical study on influence factors of parking price in urban CCDs

Authors: CHENG Tiexin, WANG Xin, CHEN Jingzhu
PP: 1088-1094
Abstract: With the increase of the number of automobiles, parking price of central commercial districts (CCDs) is the issue of the city traffic demand management. According to the domestic and foreign research on the influence factors of parking price, this paper emphasized on the comparison analysis of several influence factors of parking price in CCDs. Four influence factors, such as market circumstance, government, parker and traffic environment of parking prices for urban CCDs were provided, and a parking price influence factor model based on structure equation model (SEM) was set up. Then, a survey was made and the results illustrated that the model was applicable and practicable.
Keywords: transportation system engineering; parking pricing; structure equation model; central commercial districts

Title: Research on the implementation feasibility of berth and unberth on domestic LNG terminals at night

Authors: GENG Jiezhe, LI Xuedong, LI Yabin
PP: 1084-1087
Abstract: This paper analyzed the problem of prohibiting berth and unberth on domestic liquefied natural gas (LNG) terminals at night, surveyed the international practices and regulations on berth and unberth at night, summarized the domestic favorable conditions for berth and unberth at night and offered reference suggestions. Then, this paper analyzed the risk of berth on Dapeng LNG terminals of Shenzhen at night. This research can promote exploration on domestic LNG terminal berth and unberth at night, and provide some references for authorities on formulating LNG ship navigation at night regulations.
Keywords: transportation planning and management; waterborne transportation; investigation and analysis; liquefied natural gas; navigate at night; feasibility

Title: Discussion on the academic research on fleet planning

Authors: XIE Xinlian
PP: 1078-1083
Abstract: To explore the optimization of composition and utilization of a large scale fleet with multi-types of ships running on a number of routes under complicated circumstances, academic research progress and puzzles regarding fleet planning were summarized and analyzed in depth. It was suggested that the present mathematic models and their solution algorithms should be compared and categorized in the first place and then their academic and practice features should be induced for further improvement. Based on these works, the latest technologies in decision science should be employed to build up the optimization models that could deal with mix integer variables normally existed in fleet planning problems. In addition, special algorithms that could quickly solve the optimization models also needed to be developed for practical use. Finally, it was pointed out that the outcomes of academic research in fleet planning could not only help to optimize large scale fleet in reality, but contribute to the discipline of transportation planning and management, and these outcomes might find their applications in similar circumstances of aviation and road transportations.
Keywords: transportation planning and management; fleet planning; review; vehicle allocation; fleet management

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