被动柔性防护网结构耗能器力学性能研究

发布时间：2019-03-30 15:46

【摘要】：被动柔性防护网是一种先进的落石灾害防护结构,于上世纪90年代引入我国,广泛应用于铁路、公路沿线的落石灾害防治工程。耗能器作为被动柔性防护网结构的能量缓冲装置,吸收了落石的冲击动能,降低了整体结构的荷载峰值,是防护网结构关键的耗能构件之一。因此,研究并优化耗能器的力学性能,能够有效改进被动柔性防护网结构的耗能能力。本文对两种国内外常见的被动柔性防护网结构耗能器的力学性能进行了研究。1.采用有限元方法对GS8000型减压环在拉伸变形过程中的受力特点和能量消耗规律进行了研究。研究表明,在减压环拉伸过程中,钢管内环应力大于外环应力,且钢管最大应力发生在钢管内环靠近拉伸端处。在整个拉伸过程中,铝管受力相对较小,但有着较高的应变率。减压环最主要的耗能途径是摩擦耗能,其次是变形耗能。在减压环的总摩擦耗能中,钢管与铝管的摩擦耗能所占比例最大,其次是钢管与钢管之间的摩擦耗能。分析了减压环在过盈装配过程中的受力情况,给出了减压环过盈装配预紧力以及钢管和铝管装配应力的计算公式。2.以U-150耗能器为例,建立了 U型耗能器的有限元模型,分析了 U型耗能器的受力特点和耗能原理。研究结果表明:正常工作时,U型耗能器在各个时刻的受力状态变化不大,其拉伸端应力较大,最大应力发生在钢板与滚轴相接触的部位。U型耗能器的耗能主要来自于钢管塑性变形耗能以及钢板和滚轴之间的摩擦耗能。减小滚轴直径可增大U型耗能器的耗能能力,但会增加其启动荷载。增大钢板厚度、宽度和长度可以增大U型耗能器的耗能能力,且增大钢板宽度对增大U型耗能器耗能能力的效果最好。
[Abstract]:Passive flexible protective net is a kind of advanced stone fall disaster protection structure. It was introduced into our country in the 1990s, and is widely used in the prevention and control of stone fall disaster along the railway and along the highway. As the energy buffering device of the passive flexible protective net structure, the energy dissipation device absorbs the impact kinetic energy of the falling rock, reduces the peak load of the whole structure, and is one of the key energy dissipation components of the protective net structure. Therefore, the study and optimization of the mechanical performance of the damper can effectively improve the energy dissipation capacity of the passive flexible protective net structure. In this paper, the mechanical properties of two kinds of passive flexible protective net structure dampers at home and abroad are studied. The mechanical characteristics and energy consumption of GS8000 decompression ring during tensile deformation were studied by finite element method. The results show that the inner ring stress is greater than the outer ring stress in the process of decompression ring stretching and the maximum stress occurs near the tensile end of the steel pipe inner ring. In the whole drawing process, the stress of aluminum tube is relatively small, but it has a higher strain rate. The main energy dissipation way of decompression ring is friction energy dissipation, then deformation energy dissipation. Among the total friction energy dissipation of the reducing ring, the friction energy consumption between the steel pipe and the aluminum pipe is the largest, and the friction energy dissipation between the steel pipe and the steel pipe is the next. The stress of vacuum ring during interference assembly is analyzed, and the pretightening force of interference assembly of vacuum ring and the calculation formula of assembly stress of steel pipe and aluminum pipe are given. 2. The finite element model of U-type energy dissipator is established by taking U-type energy dissipation device as an example. The force characteristics and energy dissipation principle of U-type energy dissipation device are analyzed. The results show that under normal working conditions, the stress of U-type energy dissipator varies little at each time, and the stress at the tensile end of U-type energy dissipator is larger than that of U-type energy dissipator. The maximum stress occurs in the contact area between steel plate and roller. The energy dissipation of U-type energy dissipator mainly comes from the energy dissipation of plastic deformation of steel pipe and friction energy between steel plate and roller. Decreasing the diameter of roller can increase the energy dissipation capacity of U-type energy dissipator, but it will increase its start-up load. Increasing the thickness, width and length of steel plate can increase the energy dissipation capacity of U-type energy dissipator, and increasing the width of steel plate has the best effect on increasing the energy dissipation capacity of U-type energy dissipation device.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U213.155;U417.1

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