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301.
营运中的盾构隧道在邻近施工时周围地盘的应力可能因扰动而重新分布,使得盾构隧道暴露在因变形或位移衍生的结构损坏或营运中断等高风险下。为降低相关风险发生的可能性或后果的严重性,高雄计划将高雄车站段地下化工程捷运-R11永久站施工纳入风险管理,通过风险辨识、分析、评估以及以监测、巡检及沟通为基础的风险追踪查核等手段执行风险管理。依本计划执行成果,位于基地两侧营运中的盾构隧道在永久站主体工程开挖施工期间,各项风险均受到妥善的追踪、管控及处置。 相似文献
302.
A wheel tracking test was modelled to gain better understanding of the deflection and stress-strain distribution in an overlaid cracked pavements with and without membrane interlayer (SAMI). For this purpose, commercial finite element software Abaqus 6.7-1 was used. Two different models were considered, one incorporating stress absorbing membrane interlayers (SAMIs) and the other without SAMI. In the study, full bond condition was assumed for the boundaries between the layers, and a linear elastic model was used for the analysis. The results show that introduction of SAMI caused greater deflection of the pavement. It is found that although with SAMIs, low stiffness is required, a very low stiffness may yield undesirable results. The results show that the introduction of SAMIs results in high strain concentration around the crack region, whilst the strain in the overlay is smaller than the values predicted in the models without SAMIs. 相似文献
303.
针对运营期高铁隧道衬砌结构在飞机降落冲击荷载作用下的动力响应规律及疲劳损伤问题,以成自高铁下穿天府机场东二跑道区间隧道为工程背景,采用有限元分析的方法研究隧道动力响应及疲劳损伤规律。结果表明:B747-400型飞机在粗暴着陆后0.05 s时刻动力载荷达到最大值,约为500 kN;在单次粗暴着陆工况下,拱顶位移和受力最大,位移最大峰值为1.58 mm,拉应力最大峰值为437.79 kPa,压应力最大峰值为556.24 kPa,衬砌结构未出现塑性损伤;飞机荷载长期作用下,随着循环次数的增加,结构损伤部位和程度也随之增加,拱顶损伤最突出,其次为边墙,隧道衬砌在上方飞机长期粗暴着陆作用下的疲劳寿命大致为25 a。 相似文献
304.
D. H. Koo J. C. Kim W. H. Yoo T. W. Park 《Transportation Research Part D: Transport and Environment》2002,7(6)
Wheel/rail interaction is a major source of railway noise. A low-noise wheel structure is developed and its effect on noise reduction is investigated. This low-noise wheel employs a rubber material inserted into the steel rim or mounted on the wheel surface. The low-noise wheel has low stiffness and a high-damping ratio compared to a solid wheel. Measurement shows that it reduces rolling and squealing. It turns out that a subway line with the proposed wheel could reduce its interior noise level by 4–5 dB(A) and vehicle vibration level by 7–8 dB. While the proposed structure seems promising in noise reduction for railway vehicles, the endurance and cost effectiveness of the low-noise wheel are yet to be verified. 相似文献
305.
306.
Fuel economy comparison of conventional drive trains series and parallel hybrid electric step vans 总被引:1,自引:0,他引:1
S. B. Han Y. H. Chang Y. J. Chung E. Y. Lee B. Suh A. Frank 《International Journal of Automotive Technology》2009,10(2):235-240
A hybrid electric vehicle (HEV) is a vehicle that combines a conventional propulsion system with an on-board rechargeable
energy storage system to achieve better fuel economy than a conventional vehicle HEVs do not have limited ranges like battery
electric vehicles, which use batteries charged by an external source. The different propulsion power systems may have common
subsystems or components. The objective of this study is to compare the fuel economies of a conventional step van, a series
hybrid electric step van (HESV), and a parallel HESV by calculating the fuel consumption using the ADVISOR software by NREL.
We also showed the results of the vehicles in different driving cycles including the Central Business District bus cycles,
the New York City Cycle, and the US EPA City and Highway cycles. 相似文献
307.
Analysis of a regenerative braking system for Hybrid Electric Vehicles using an Electro-Mechanical Brake 总被引:3,自引:0,他引:3
J. K. Ahn K. H. Jung D. H. Kim H. B. Jin H. S. Kim S. H. Hwang 《International Journal of Automotive Technology》2009,10(2):229-234
The regenerative braking system of the Hybrid Electric Vehicle (HEV) is a key technology that can improve fuel efficiency
by 20∼50%, depending on motor size. In the regenerative braking system, the electronically controlled brake subsystem that
directs the braking forces into four wheels independently is indispensable. This technology is currently found in the Electronic
Stability Program (ESP) and in Vehicle Dynamic Control (VDC). As braking technologies progress toward brake-by-wire systems,
the development of Electro-Mechanical Brake (EMB) systems will be very important in the improvement of both fuel consumption
and vehicle safety. This paper investigates the modeling and simulation of EMB systems for HEVs. The HEV powertrain was modeled
to include the internal combustion engine, electric motor, battery and transmission. The performance simulation for the regenerative
braking system of the HEV was performed using MATLAB/Simulink. The control performance of the EMB system was evaluated via
the simulation of the regenerative braking of the HEV during various driving conditions. 相似文献
308.
Model-based control system design in a urea-SCR aftertreatment system based on NH3 sensor feedback 总被引:1,自引:0,他引:1
M. Devarakonda G. Parker J. H. Johnson V. Strots 《International Journal of Automotive Technology》2009,10(6):653-662
This paper presents preliminary control system simulation results in a urea-selective catalytic reduction (SCR) aftertreatment
system based on NH3 sensor feedback. A four-state control-oriented lumped parameter model is used to analyze the controllability and observability
properties of the urea-SCR plant. A model-based estimator is designed via simulation and a control system is developed with
design based on a sliding mode control framework. The control system based on NH3 sensor feedback is analyzed via simulation by comparing it to a control system developed based on NOx sensor feedback. Simulation results show that the NH3 sensor-based strategy performs very similarly in comparison to a NOx sensor-based strategy. The control system performance metrics for NOx index, urea index, urea usage, and NH3 slip suggest that the NOx sensor can be a potential alternative to a NOx sensor for urea-SCR control applications. 相似文献
309.
H. -D. Kang D. -H. Kim S. -W. Chae J. -N. Han D. -S. Kim 《International Journal of Automotive Technology》2009,10(5):583-587
Most of the research on safety belt systems has involved crash simulation that only considered a dynamic human model. However,
belt routing analysis, usually known as comfort level estimation, is also an important factor in safety belt design, considering
that serious injuries of the abdominal region result from the infiltration of a belt into the neck or the chest. Thus, safety
belt evaluations using kinematic human models are also needed. In this paper, a belt fit simulation method is suggested. Using
the proposed process, both comfort and safety analyses can be performed under the same conditions continuously, and thus the
safety belt design parameters, such as the location of anchor points, dummy posture and etc., can be evaluated. In conclusion,
this computer process enables a belt system design to reduce injuries. 相似文献
310.
W. B. Hou H. Z. Zhang R. F. Chi P. Hu 《International Journal of Automotive Technology》2009,10(2):175-180
The concept design phase is a critical step in auto-body design, as it has a great effect on later design work. This paper
describes the implementation of an auto-body structure design in the early stages of a new auto-body developing program. In
order to reduce the long design period and analysis error that plagues traditional auto-body concept design, an intelligent
CAE system has been successfully developed and implemented based on the UGS NX/API opening platform. This system, the so-called
ACD-ICAE (Auto-body concept design-intelligent computer aided engineering) System that means concept design-intelligent computer
aided engineering system, employs a fully parametrized template method to build the conceptual auto-body geometry model and
FEM model quickly and easily. It also integrates auto-body modeling, analysis and optimization on only one CAD platform via
a parametric variables database. Moreover, all parametric variables are shared and updated in different phases of the ACD-ICAE
System. A wizard User Interface (UI) based on knowledge of auto-body engineering was developed and used in this system. The
procedures implementing the functional diagram of the ACD-ICAE system are also provided. A typical example of a car body concept
design with four doors shows that the ACD-ICAE system is efficient and accurate. 相似文献