Structural Analysis and Experimental Study for realsized MB Travelable Vehicles
Structural Analysis and Experimental Study for realsized MB Travelable Vehicles
复制标题
实现MB移动车辆的结构分析与实验研究
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
C. Graczykowski
中科院分区：
文献类型：
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作者：
Y. Chikahiro;I. Ario;M. Nakazawa;S. Ono;J. Holnicki;P. Pawłowski;C. Graczykowski
摘要许多自然灾害，如地震，洪水，暴雨发生在世界各地，我们采取快速救援行动。但由于各救援现场次生灾害的发生，存在着许多恢复问题。因此，在前人对MFM的结构优化和控制规律研究的基础上[1]-[2]，我们提出了一种新型的剪刀式折叠桥--移动的桥[3]。移动的桥将剪叉机构应用于桥梁结构中，不仅具有良好的机动性，而且由于整个桥梁可以快速展开或折叠，因此具有良好的结构性能。本文通过对真实的比例移动的桥梁上车辆通过试验的研究，对该桥梁的设计方法和应用范围进行了评价。使用真实比例的移动的桥进行车辆通过试验实验移动的桥的开发图1中给出了真实的尺寸的移动的桥（称为MB 1. 0）的实验两单元剪刀模型的示意图。当开始向对岸海岸展开时，构件逐渐倾斜，跨度扩大，如图1（a）所示。此外，MB1.0还配备了一个可折叠的地板甲板，遵循部署过程。桥梁扩建后，边界条件由悬臂梁变为简支梁，车辆通行较少，如图1（B）所示。在原型MB1.0的运行状态下，跨度的总长度为7.0m，高度为2.0m。考虑到主要构件、轴、销等结构部件，MB1.0的总重量为8.6kN。为了减轻自重，车架和甲板的主要构件均采用铝合金材料制成。此外，地板甲板减少到两个平行的狭窄件上的车轮负荷的作用。车辆通过试验的概述两种车辆，STREET和AD货车，用于车辆装载试验。STREET是轻型车辆，AD货车是标准尺寸的汽车。STREET（长 * 宽 * 高）为（3195 mm * 1395 mm * 1870 mm），AD货车（长 * 宽 * 高）为（4370 mm * 1895 mm * 1510 mm）。STREET的重量为7.9kN，AD货车的重量为12.3kN，司机的重量除外。对五种载荷情况进行了测量。当前轮、车轴（此处定义为前轮和后轮的中间部分）和后轮到达特定点并停止时，测量静态应变的值。停止位置是第一个单位剪刀的甲板中心和MB1.0的中心部分。有限元分析采用Autodesk公司的AutoCAD Inventor二维框架分析验证。利用嵌入在CAD中的内部程序（ANSYS）进行分析是可能的。在数值模拟过程中，使用梁单元，并进行了分析的每个位置的车辆移动和停止。本文仅显示了MB1.0在跨度中心加载车辆的选定情况。模型如图2（a）和（B）所示。在包括甲板的完整模型中，自重包括主框架、轴和甲板（图2（a））。图2（B）中描述的简化模型被认为是桥面的刚度。在完整模型中，车轮载荷施加到甲板上的位置，车辆停在该位置，如图2（a）所示。如图2（B）所示，简化模型载荷被建模为作用在销上的等效节点力。红色箭头表示的活荷载根据车轮荷载作用，黄色箭头表示等效节点力。作为边界条件，两端的轴部分是固定销支撑。
Summary. Many natural disasters such as earthquakes, floods, torrential rains occur around the world, and we to undertake quick rescue actions. However, there are many recovery problems because of the occurrence of secondary disasters at each rescue worksite. So, from the previous study of optimal structures and control regulation of MFM[1]-[2], we propose a new type of foldable bridge with scissors structure called Mobile Bridge[3]. Applying scissors mechanism to bridge form, Mobile Bridge provides not only mobility but also good structural performance, because the whole bridge can be expand or fold quickly. In this paper, we discuss the vehicles passing test on the real scale Mobile Bridge in order to evaluate the design method and application limits. Vehicle passing test using real-scaled Mobile Bridge Development of the experimental Mobile Bridge The schematic view of the experimental two units scissors model for a real sized Mobile Bridge (called as MB1.0) is presented in Fig.1. When deployment starts toward the opposite shore, the structural members are inclined gradually and the span is extended as shown in the Fig.1(a). Moreover, the MB1.0 is equipped with a foldable floor deck which follows the process of deployment. After the bridge is expanded, boundary conditions are changed from cantilever to simplysupported beam, and few vehicles can pass the bridge as shown in Fig.1(b). In operational state of the prototype MB1.0, the total length of the span is 7.0m and the height is 2.0m. The total weight of the MB1.0 considering the structural parts such as the main members, the shafts, the pins is 8.6kN. To reduce the dead weight, the main members of the frame and deck are made of aluminum alloy material. Moreover, the floor deck is reduced to two parallel narrow pieces on which wheel load acts. Outline of vehicle passing test Two kinds of vehicles, STREET and AD van, were used for the vehicles loading test. The STREET is a light vehicle and the AD van is a standard-sized car. The STREET’s (length*width*height) is (3195mm*1395mm*1870mm), while the AD van’s (length*width*height) is (4370mm*1895mm* 1510mm). The weight of the STREET is 7.9kN and AD van is 12.3kN except the weight of driver. The measurement was performed for five load cases. When the front wheel, the axle (defined here as the intermediate part of the front and the rear wheel), and the rear wheel came to a specific point and stopped, the value of the static strain was measured. The stop positions were the center of the deck for the first unit scissors and the central part of the MB1.0. Verification of the 2D-frame analysis AutoCAD Inventormade by AutodeskCompany was used for this FE analysis. The analysis was possible by using internal program (ANSYS) which was embedded in the CAD. During the numerical simulations beam elements were used, and the analysis was performed for each position of the vehicle moving and stopping. This paper shows only selected cases in which the MB1.0 is loaded with a vehicle in the center of the span. The models are shown in Fig.2(a) and (b). In the full model including the deck, the dead weight consists of the main frames, shafts and the decks (Fig.2(a)). The simplified model depicted in Fig.2(b) is considered the stiffness of the deck. In the full model, the wheel loads are applied to the deck in the position, in which the vehicle stopped as shown in Fig.2(a). The simplified model loads are modelled as equivalent nodal forces acting on the pins, as shown in Fig.2(b). The live load, as denoted by the red arrow acts according to the wheel loads, and the yellow arrow denotes the equivalent nodal forces. As a boundary condition, the shaft part of both-ends are fixed-pin supports.