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1.
Anti-ram bollards used in perimeter protection are tested to meet performance requirements of established standards such as the US Department of State Specification SD-STD-02.01. Under these standards, tests are conducted in prescribed conditions that should be representative of the service installation. In actual project, conditions encountered on site may vary from the test environment and it would be expensive and time consuming to validate each deviation with a physical test. High-fidelity physics-based (HFPB) finite element modeling can provide precise simulations of the behavior of anti-ram bollards. This paper presents the use of HFPB finite element modeling, using LS-DYNA, in an actual project to evaluate the performance of an anti-ram bollard design subjected to various boundary conditions representing the physical conditions encountered on site. The study shows that boundary conditions can have a significant influence on the performance of the anti-ram bollards. This suggests that anti-ram bollards must be designed and engineered according to actual conditions that are found on site. It also shows that HFPB modeling can be an effective tool that supplements physical testing of anti-ram bollards. 相似文献
2.
Mohammad Khajehzadeh Mohd Raihan Taha Ahmed El-Shafie Mahdiyeh Eslami 《浙江大学学报(A卷英文版)》2011,12(6):415-427
This paper deals with the economically optimized design and sensitivity of two of the most widely used systems in geotechnical
engineering: spread footing and retaining wall. Several recent advanced optimization methods have been developed, but very
few of these methods have been applied to geotechnical problems. The current research develops a modified particle swarm optimization
(MPSO) approach to obtain the optimum design of spread footing and retaining wall. The algorithm handles the problem-specific
constraints using a penalty function approach. The optimization procedure controls all geotechnical and structural design
constraints while reducing the overall cost of the structures. To verify the effectiveness and robustness of the proposed
algorithm, three case studies of spread footing and retaining wall are illustrated. Comparison of the results of the present
method, standard PSO, and other selected methods employed in previous studies shows the reliability and accuracy of the algorithm.
Moreover, the parametric performance is investigated in order to examine the effect of relevant variables on the optimum design
of the footing and the retaining structure utilizing the proposed method. 相似文献
3.
Road side barriers are constructed to protect passengers and contain vehicles when a vehicle crashes into a barrier. In general, full-scale crash testing needs to be carried out if a geometrically and structurally equivalent barrier has not previously been proven to meet the requirements of containing the vehicle and dissipating sufficient impact energy for passenger protection. As full-scale crash testing is very expensive, the number of data that can be measured in a test is usually limited, and it may not always be possible to obtain good quality measurements in such a test, a reliable and efficient numerical simulation of crash testing is therefore very useful. This paper presents finite element simulations of a 3-rail steel road traffic barrier under vehicle impact. The performance levels defined in Australian Standards AS5100 Clause 10.5 for these barriers are checked. The numerical simulations show that the barrier is able to meet low performance levels. However, the maximum deceleration is higher than the acceptable limit for passenger protection. If present, a kerb launches the vehicles into the barrier, allowing for the possibility of overriding the barrier under certain circumstances, but it redirects the vehicle and reduces the incident angle, which reduces impact force on the barrier. Further investigation into all common kerb profiles on roads should be carried out, as only one kerb profile is investigated in this study. 相似文献
4.
The main topic of this article is architectural barriers and infrastructures as identified by university students with disabilities. The data presented is part of a much wider research project, sponsored by Spain’s Ministry of Economy and Competition. A biographical-narrative methodology was used for this study. The results presented have been classified based on one of five barrier types: urban (barriers that are outside the actual university campus), transport (public transportation and personal vehicles), building (obstacles inside university buildings), environmental (those elements within the classroom, including furniture, excessive noise or inadequate temperatures) and communication (these are divided into signposting and barriers when accessing information). Lastly, a variety of questions are considered in the conclusions which indicate that universities still need a certain degree of adaptation and readjustment to really be accessible and inclusive, in keeping with the principles of universal design. 相似文献
5.
余捷 《福建工程学院学报》2017,(1):26-29
为进一步提高车辆动力性和经济性,针对车辆传动系速比进行整车仿真与优化设计。为有效解决多目标优化问题,将整车动力性指标作为约束条件、经济性为优化目标进行Cruise和Isight联合仿真。结合某四驱车辆传动比原始数据,速比优化仿真结果显示,车辆的性能有较好地提升。 相似文献
6.
综合布线系统是智能建筑及建筑群的重要基础设施，伴随着全球信息化过程的不断加快和信息产业的迅速发展，对综合布线工程电气设计的要求也就越来越高。章对综合布线设计中涉及的保护接地和屏蔽接地进行了探讨。 相似文献
7.
为了更好地满足电动车防盗需求,提高被盗电动车辆追踪效率、节约时间并降低人力成本,基于RFID技术设计了电动车防盗监控平台。平台由Web服务器集群、Nginx负载均衡器与数据库组成,阐述了平台各部分设计并进行性能测试。测试结果表明,该电动车防盗平台运行稳定、易于操作,能够在车辆被盗时及时帮助失主找回车辆,可基本满足电动车防盗的业务需求,并且能够较好地应对高并发访问。 相似文献
8.
在车辆监控系统中,通过电子地图可以直观的掌握车辆的动态信息,因此电子地图的设计和实现是车辆监控系统设计的重点。探讨MapX控件在车辆监控系统中的具体应用,在分析车辆监控系统的组成和工作原理基础上,针对电子地图所需完成的功能,采用VB开发工具,集成MapX控件,实现车辆定位、轨迹回放、目标模糊查询等功能。重点说明最短路径分析功能,完成车辆监控系统中电子地图模块的设计。 相似文献
9.
达国军 《思茅师范高等专科学校学报》2010,26(3):137-140
建筑室内消火栓系统的水力及水量计算是消火栓系统设计的一个重要环节,正确计算消火栓系统水力及水量对发挥系统灭火作用、扑救建筑物火灾能起到至关重要的作用。通过对多层建筑室内消火栓系统水力及水量计算的演示,为建筑消防设施设计人员提供参考。 相似文献
10.
新工科背景下,为了适应新能源汽车产业的蓬勃发展,培养新能源汽车专业人才已成为车辆工程专业教学的重要任务。在探讨面向新工科建设的新能源汽车专业方向相关课程教学形成性评价实施思路的基础上,提出了以增强工程实践能力为目标的形成性评价教学措施,旨在为新能源汽车专业方向相关课程教学中形成性评价的实施与应用提供参考。 相似文献
11.
Aman CHITRAKAR LIU Fei CAO Hua-jun HE Yan 《重庆大学学报(英文版)》2006,5(1):1-7
1 Introduction With the increase in the number of vehicles beingused in our human society, the numbers of vehiclesarriving at their end-of-life stage are also in increase. Inthe context of the issuance of ELV managementdirectives by EU[1], the management … 相似文献
12.
In the structural design of tall buildings, peak factors have been widely used to predict mean extreme responses of tall buildings
under wind excitations. Vanmarcke’s peak factor is directly related to an explicit measure of structural reliability against
a Gaussian response process. We review the use of this factor for time-variant reliability design by comparing it to the conventional
Davenport’s peak factor. Based on the asymptotic theory of statistical extremes, a new closed-form peak factor, the so-called
Gamma peak factor, can be obtained for a non-Gaussian resultant response characterized by a Rayleigh distribution process.
Using the Gamma peak factor, a combined peak factor method was developed for predicting the expected maximum resultant responses
of a building undergoing lateral-torsional vibration. The effects of the standard deviation ratio of two sway components and
the inter-component correlation on the evaluation of peak resultant response were also investigated. Utilizing wind tunnel
data derived from synchronous multi-pressure measurements, we carried out a wind-induced time history response analysis of
the Commonwealth Advisory Aeronautical Research Council (CAARC) standard tall building to validate the applicability of the
Gamma peak factor to the prediction of the peak resultant acceleration. Results from the building example indicated that the
use of the Gamma peak factor enables accurate predictions to be made of the mean extreme resultant acceleration responses
for dynamic serviceability performance design of modern tall buildings. 相似文献
13.
汽车悬架的主动控制非常困难，特别是要处理越野汽车的舒适性和操纵性。越野汽车的悬架位移量非常大，非线性时变特性和阻尼特性非常显。一种能提高主动悬架系统的效率的方法是：保留线性控制方法的优点，同时用线性回馈方法识别并取消非线性特性。介绍了主动悬架的控制策略和军用越野汽车的一种控制方法。 相似文献
14.
新型铁道双层集装箱运输车是新研制的货车车型，新车型的设计与制造需要更多的科学依据。本文应用JIFEx软件对车体结构进行了多种工况的有限元分析和重量、刚度、应力、自振频率等多种务件的优化设计，为更加合理、经济的车体结构设计提供科学依据。 相似文献
15.
The meanings of the words microcircuits, molecular electronics, integrated circuits, and functional devices are examined with the conclusions that, as generally used, the only sensible definitions are as follows: a microcircuit is one in which connections are made between circuit elements on a microscopic scale. Molecular electronics, integrated circuits, and functional devices all have essentially the same meaning, which is that connections are made between circuit elements inside a single block of material without bringing leads out. The next order of miniaturization that is required for space vehicles and large-scale computers will use a microeletronic or molecular electronic technology in combination with conventional miniature techniques. The feasibility of very large components of systems being made by a molecular or microelectronic technique depends on the combination of many orders of magnitude reduction in manufacturing shrinkage combined with the design of circuits to tolerate unreliable or defective elements. 相似文献
16.
为了解决诸如沙漠、戈壁等广袤荒漠场景集团车辆通信问题,提出了基于卫星通信和基于高空平台通信 2 种车辆间组网模型,并给出了这 2 种模型的系统框架和组网模式. 在基于卫星通信模型中,所有车辆均配备车载"动中通"卫星通信终端,车辆间通信信号由卫星转发. 在基于高空平台通信模型中,装载基站设备的高空平台形成了空中基站,车辆使用普通地面移动通信设备即可通信. 此外,对路径损耗、链路损耗和系统容量等关键参数进行了计算. 分析结果表明,所提出的 2 种模型能够满足所述场景车辆间的通信需求. 相似文献
17.
高吕和 《北京工业职业技术学院学报》2012,11(3):20-24
通过对教学用小型纯电动车的需求进行分析,确定了基本参数。依据电池参数与整车性能的关系,进行了电池的材料选择。按照车辆行驶工况进行了电池的电压、容量参数的设计,根据设计结果进行了电池的选型,并对其进行了容量测试,验证其满足电池模块设计要求。 相似文献
18.
为了推进绿色港口纯电动无人驾驶系统的研究和应用,研发了一套新的自主车辆交通协同控制与仿真工具。将半实物仿真技术充分应用于港口物流系统的有效模拟,建立了多智能车辆交通控制模型,创新地提出了一种面向全局优化的交通实时预留调度方法,具有模块化设计、虚实融合、低成本等技术特点和优势,可用于港口码头的辅助规划设计、软件开发测试和员工培训,也可作为高校教学科研的创新实验工具。 相似文献
19.
Giuseppe Carlo Marano 《浙江大学学报(A卷英文版)》2008,9(1):15-25
Based on a multiobjective approach whose objective function （OF） vector collects stochastic reliability performance and structural cost indices, a structural optimization criterion for mechanical systems subject to random vibrations is presented for supporting engineer＇s design. This criterion differs from the most commonly used conventional optimum design criterion for random vibrating structure, which is based on minimizing displacement or acceleration variance of main structure responses, without considering explicitly required performances against failure. The proposed criterion can properly take into account the design-reliability required performances, and it becomes a more efficient support for structural engineering decision making. The multiobjective optimum （MOO） design of a tuned mass damper （TMD） has been developed in a typical seismic design problem, to control structural vibration induced on a multi-storey building structure excited by nonstationary base acceleration random process A numerical example for a three-storey building is developed and a sensitivity analysis is carried out. The results are shown in a useful manner for TMD design decision support. 相似文献
20.
介绍一种实用的车辆系统里程计检测装置的设计方法，对此里程计检测装置的电机驱动电路、里程显示电路、键盘扫描电路、传感电路等硬件电路进行了分析，并根据每一部分的特点阐述了相应的设计原理。这一方法对于该类装置的设计和实际使用均有参考价值。 相似文献