LAN Shengrui; CRAWFORD John E; XIN Xudong
In past terrorist attacks,vehicle borne improvised explosive devices (VBIED) have been the primary manner of attacking buildings and infrastructures.Preventing unauthorized vehicles from approaching a protected area with anti-ram systems would maintain an established standoff distance against moving and stationary vehicles and consequently reduce blast and debris threats.This strategy has been considered the first line of defence against terrorists.Several types of anti-ram devices have been developed in accordance with U.S.Department of State K-rating criteria,for example,wedge barriers,rising beams,sliding/swing gates,and drop arms.However,these devices typically need a deep foundation for installation and can't be implemented into many locations where a depth of excavation is limited in order to protect utility lines of buildings and infrastructures.This paper presents a recent development of a series of shallow footing anti-ram bollard systems (SFABS) that can satisfy K-12 rating with only five-inch thick footing.A high-fidelity physics based finite element technique with a vehicle crash model is used for predicting anti-ram capacity and determining design parameters of the SFABS.Full-scale vehicle crash tests of the developed SFABS systems have been carried out to validate the design and analysis.
肖岩; 陈林; 肖果; 陈柏生; 刘春霖
针对目前防撞柱研究只停留于软件分析问题,详细介绍研发的结构防撞实验设施及利用该设施完成的钢管混凝土防撞柱系统实车碰撞试验.试验用撞击卡车加配重总重6.8t,发生撞击时速度约12 m/s,卡车货厢前沿未穿过碰撞前的防撞柱内侧边缘即被完全阻止,符合规定的防撞柱K4等级要求.对防撞柱进行静力推覆对比试验,获得防撞柱荷载-挠度曲线,并据此对碰撞试验的能量转换进行分析.获得卡车与柱状物撞击时卡车前部变形刚度系数及最大撞击力计算公式,并提出防撞柱的简化设计方法.%Bollards are more and more utilized in guarding important buildings against potential attack by terrorists using car bomb.Most existing studies on bollards typically only stay in an analysis phase and experimental studies are quite rare.Here,a new facility for testing car collisions with structures or transportation facilities was developed.An actual truck collision test was conducted to study the effectiveness of a newly designed concrete filled tubular anti-ram bollard system.The total weight of the collision truck was 6.8 tons.During collision,the speed of the truck was about 12m/s.The collision test results showed that the front edge of the cargo bed does not reach the pre-impact inside edge of the bollard,the collision truck is completely stopped,in full compliance with the K4 level according to the U.S.standard SD-STD-02.01.The load versus deflection curve was obtained through the comparative static test of the bollard.The energy conversion in the collision test was analyzed.According to the simplified analysis of the collision test,the formulas for the deformation stiffness of the front of the truck and the maximum impact force were obtained and a simplified design procedure was proposed.
王震; 李国强; 陈素文; 孙建运
近年来发生的规模较大的恐怖袭击活动中,车载简易爆炸装置(VBIED)逐渐成为建筑结构与基础设施安全的重大危害.防撞杆作为重要建筑周边的第1道安全屏障,能够有效地控制潜在威胁车辆对建筑物的侵入.因此,以防撞杆为代表的阻拦型防爆路障在英、美等发达国家已有广泛应用.为了规范阻拦型防爆路障的试验测试及评定标准,英、美等国都相继颁布了本国阻拦型防爆路障的评测规范,其中美国规范中提出了一套K级抗撞等级标准.利用显式动力分析软件LS-DYNA的强大模拟功能,结合美国规范中的K4等级对应工况,提出了一套适用于钢管混凝土防撞杆的简化设计方法,可供今后的工程应用参考.%In past large-scale terrorist attacks, vehicle-borne improvised explosive devices ( VBIED) have become the major hazard for the safety of buildings and infrastructures. As the first line of defense against terrorism,anti-ram bollards could control the penetration ofvehicles with potential threat to buildings effectively. Therefore,anti-ram bollards have been widely used in the developed countries, such as U. S. and Britain. In order to adopt a unified test and evaluation standard of vehicle barriers,the governments of U. S. and Britain have established standards for vehicle barrier devices respectively. A criterion of K-level was given in the U. S. specification. By using of the LS-DYNA software.this paper presents a simplified design method of anti-ram bollards subject to vehicle impact load according to the K4 level,which could give a reference for the future engineering design.
... bollard pull of the vessel; (ii) Appropriate for the static loads and dynamic loads expected during the... spools and tightly winds the towline; and (7) If a winch is fitted, there is attached to the main drum...
Valero Martínez, Marta; Zamora Alvarez, Tomas Augusto; Fayos Sancho, Juan; Cerda Casanoves, María Reyes; GARCIA MOLINA, CARLOS; Olaso Melis, Jose; Laparra Hernandez, Jose; Baydal Bertomeu, José Mª
[EN] The ECO-RUBBER project has implemented the design and manufacture of recycled urban furniture through an innovative process of grinding and sintering. The key differentiation has been the use of recycled rubber from end- of-life tyres (ELT) and its application into urban environment to make a city more sustainable, secure and friendly to its inhabitants. The experimental proposal developed a bollard made of 89% recycled material with new functionalities that reduce the risk of an injury ...
Noonan, Daniel Richard
The following thesis project is an investigation in the topic of security through design. The study sought a site and program susceptible to attack in the public environment in order to design an appropriate response to the inherent tension from those attributes. The work represents an architectural reaction to the engineered assessments and solutions that permeate the post 9/11 world. The seemingly indiscriminate deployment of bollards, planters, and jersey barriers choke the ...
ABSTRAK Mooring dolphin adalah bagian yang sangat penting dan tidak terpisahkan pada konstruksi pelabuhan ataupun dermaga. Mooring dolphin memiliki berbagai macam jenis dan bentuk. Mooring dolphin berfungsi sebagai alat untuk menambat kapal yang berlabuh pada pelabuhan atau dermaga tersebut agar tidak bergeser jauh dari pelabuhan pada saat menerima gaya. Sehingga dengan demikian mooring dolphin yang terdiri dari tiga bagian utama yaitu, bollard, poer, dan tiang pancang yang direncanakan ...
To reduce costs and limit pollution from transportation of goods by sea, a method for optimization of the propulsive efficiency of an 8000 dead weight tonnage tanker is investigated. Emphasis is put on the interaction between the propulsion system and the hull.The optimum combination of pitch and propeller rate of revolutions is sought for a controllable pitch propeller, working behind a tanker. Two stern shapes have been examined at the vessels design speed, and in bollard pull conditi...
Although active transport is considered the most efficient way of depositing materials in the appropriate compartments within living cells, free diffusion remains the energetically cheapest and most widespread determinant of the in-cell dynamics. Here we investigate the hypothesis of cargoes - vesicles or organelles - being transported by the means of free diffusion, limited spatially by the molecular motors. Routinely navigating through ever-changing and unsteady environment, utilizing chemical energy (e.g. from hydrolyzing ATP), as the result they transport cell's crucial components, such as neurotransmitters and organelles. In our model the motor, which we identify with kinesin-1 walking along the microtubule, tethers the cargo in the same manner as a mooring rope attached to a bollard holds a ship from drifting toward the open sea. We study the model behavior in the context of optical trap single molecule experiments, mimicking their procedures in our simulations and investigate how the mechanical propert...
Vaughan, C L
Although successful models have been developed to simulate a sprinter's performance, they are often complex and sophisticated, requiring a main frame environment and expensive monitoring equipment. These disadvantages preclude the wide-spread use of the models by practitioners. This paper presents a method in which the necessary data can be easily gathered--using a tape measure, six stop watches and bollards, a starting gun, and a bathroom scale. A simple algorithm is presented for calculating the parameters of a previously defined model, and implemented on hand-held programmable calculators, the Casio FX-502P and HP41C. The model calculates the sprinter's initial horizontal acceleration, maximum horizontal velocity and can be used to predict the time for any given race distance. The model can therefore be used to evaluate the sprinter's current performance as well as indicate his potential if he were able to reach and maintain maximum velocity.
Bollard, Paul; Des Jardins, Stephen
Prior to the construction of La Provence Restaurant in Roseville, California in 2004, the owner, Stephen Des Jardins, traveled with his cook, architect, and engineer to the Provence Region of France to study the cuisine, architecture, and acoustics of the local restaurants. This information was incorporated into the design, construction, and operation of his restaurant, with acoustical design assistance provided by the author, Paul Bollard. The result of the owner's painstaking attention to detail is a restaurant which has received very positive reviews for its architecture, quality of food, service, and acoustic ambience. This paper documents the measures included in the construction of the restaurant to ensure that the building acoustics enhance the dining experience, rather than detract from it. Photographs of acoustic treatments are included, as are reverberation time (RT60) test results and ambient noise level measurement results.
CAO Qing-ming; HONG Fang-wen; TANG Deng-hai; HU Fang-lin; LU Lin-zhang
This article presents an approach which employs a commercial Reynolds-Averaged Navier-Stokes (RANS) solver to predict the steady wake field and loading distributions for a rim driven thruster.Four different cases of propeller blades are chosen to be calculated with the presented method.The propeller blade radial circulation and chordwise circulation density distributions are analyzed.The maximum radial circulation is found at the blade tip,which is different from conventional shaft drven propeller.The numerical results indicate that there is no tip leakage vortex in rim driven propulors.But there exist the tip joint vortex and the root region vortex.Bollard characteristics are calculated by taking rim surface effect into account.From the predicted results the second case in this paper is selected as the final one to perform hydrodynamic experiment.The calculation results with empirical rim surface corrections are compared with the measurement.It shows that the developed numerical method can well predict hydrodynamic performances of the rim driven thruster.
The software Inventor is an intelligent tool for 3-D mechanical design. It is used in the present study to design mechanical equipment such as steel structure, bollard, and flume with variable slope, and has efficiently and accurately solved practical engineering problems. The basic functions of Inventor are presented by introducing design examples, which shows that Inventor is a crucial tool for the description and expression of engineering techniques and scientific research results. Utilization of Inventor is a key to master engineering design, and is essential for the creativity and innovation of engineering technique and scientific research%Inventor软件是全面智能化的三维机械设计工具.应用Inventor软件设计了钢结构、系船墩、变坡水槽等机械设备,高效准确地解决了实际水力学工程问题.结合设计实例介绍了软件的基本功能,表明Inventor三维软件是工程技术及科学研究的重要工具.进一步掌握其技术和技巧,即可进入设计的前沿,辅助实现工程技术及科学研究的创意与创新.
W. Lam; G. A. Hamill; SONG Yong-chen; D. J. Robinson; S. Raghunathan
In the present study, an experimental investigation of the decay of the maximum velocity and its turbulent characteristics behind a ship propeller, in "bollard pull" condition (zero speed of advance), is reported. Velocity measurements were performed in laboratory by use of a Laser Doppler Anemometry (LDA) measurement system. Earlier researchers described that the maximum axial velocity is constant at the initial stage of a ship's propeller jet (Fuehrer and Romisch, 1977; Blaauw and van de Kaa, 1978; Berger et al., 1981; Verhey, 1983) as reported in a pure water jet (Albert.son et al., 1950; Lee et al., 2002; Dai, 2005), but a number of researchers disagreed with the constant velocity assumption. The present study found that the maximum axial velocity decays in the zone of flow establishment and the zone of established flow with different rates. The investigation provides an insight into the decays of both the maximum velocity and the maximum turbulent fluctuation in axial, tangential and radial components and the decay of the maximum turbulent kinetic energy. Empirical equations are proposed to allow coastal engineers to estimate the jet characteristics from a ship's propeller.
饶龙兵; 李霞; 段红平; 陈益泰
The experiment on four exotic alder including Alnus glutinosa, A. rubra, A. nitida and A. incana growing under four different concentrations of nitrogen was conducted in a greenhouse in order to research the alder' s responses under different nitrogen concentrations and stresses. The results showed that the growing parameters of alder on the survival percent of transplanting, plant height, ground diameter, biomass, root-top ratio, relative content of chlorophyll (SPAD) and rooting parameters (length, superficial area, volume and tips of root) were significant a-mong different materials and different nitrogen concentrations, the different level of nitrogen significantly affected the growth of alder. Specifically, the survival percent of transplanting went down with the going up of nitrogen concentration , and the plant height, ground diameter, relative content of chlorophyll and rooting parameters went up when nitrogen varied from 0 to 1/2 normal nitrogen, yet went down at one or two times of normal nitrogen (E. G. Bollard formula). The relative content of chlorophyll went up with the concentration of nitrogen increasing from 0 to 2 normal nitrogen, and its trend during one year period showed rising firstly and then descending. The relationship between the value of SPAD and biomass did not appear positive correlation. The appropriate concentration for growing on alder was 1/2 normal nitrogen. The order of performance of growth among the four alder was Alnus glutinosa, A. rubra, A. nitida and A. incana. So, A. glutinosa and A. rubra potentially could be used as plantation trees of ecological protection and short-rotation lumber in the beach and low hills of middle and lower reaches of Yangtze River.
郝军; 孙玉柱; 吴子全; Alan WANG
This paper describes the model test and the virtual simulation respectively for the VLCC class FPSO hookup, as well as addresses their different applications to the mating operation between the FPSO and the soft yoke mooring system (SYMS) in extremely shallow water. The scope of the model test and the virtual simulation covers various installation stages including a series of positioning trials, positioning keeping and temporary mooring to the pre-installed SYMS mooring tower, pendulum mating, and yoke ballasting to storm-safe. The model test is to accurately verify bollard pull capacity to keep the FPSO in position and assess motion responses and mooring loads for the FPSO and installation vessels during various installation stages. The virtual simulation is to provide a virtual-reality environment, thus realistically replicating the hookup operation at the Simulation Test Center (STC) facility and identifying any deficiencies in key installation personnel, execution plan, or operation procedures. The methodologies of the model test and the virtual simulation addressed here can be easily extended to the deepwater applications such as positioning and installation operations of various floating systems.%阐述了VLCC级.FPSO海上连接的模型试验和虚拟模拟,以及其研究结果如何应用于指导FPSO与SYMS存极浅水中的连接作业.模犁试验和虚拟模拟研究范围覆盖了各安装阶段,包括海上就位试验、就位及连接临时交义缆、系泊腿连接、压载灌浆直至达到风暴安全状态.模型试验不仅可以核实FPSO就何拖拉力要求,而且可以确定FPSO和安装驳船的运动幅值和系泊力大小.而虚拟模拟则可以虚拟模拟环境,通过虚拟模拟确认关键作业人员、作业执行方案和作业程序中潜在的问题.该文介绍的模型试验和虚拟模拟方法可以进一步推广到各种浮式平台的深水应用中.