柔性被动拦截网结构力学性能研究

发布时间：2018-01-15 15:30

本文关键词：柔性被动拦截网结构力学性能研究　出处：《西南交通大学》2014年博士论文　论文类型：学位论文

【摘要】：近30年来,我国成为全球地质灾害最严重的国家之一。针对量大面广的落石、崩塌等地质灾害,学者和工程师们提出了多种应对措施和方法,其中,柔性拦截网就是一种被广泛使用的防护措施。但是,使用表明柔性拦截网在实际工程中屡屡出现系统破坏、拦截失效等问题,其原因在于当前国内对柔性拦截网结构的工作机理认识不清,缺少有效的技术控制,加之其本身具有非常复杂的结构行为,研究成果甚少。据此,以柔性被动柔性拦截网结构为研究对象,采用足尺试验与理论分析相结合的方式,对其冲击试验方法、计算理论、结构力学行为和设计方法等问题展开研究,主要研究内容和取得成果如下：其一,开展了被动柔性拦截网结构抵抗落石冲击的足尺试验。获得了拦截网结构遭受到落石冲击作用后,全过程受力、传力、变形及运动特征,通过对高速摄像解构,得到了整体系统的变形、运动规律,揭示了主要构件的关键力学行为。其二,建立了被动柔性拦截网结构的数值计算理论。结合国内外相关的构件力学行为试验研究数据,并依据被动柔性拦截网结构的整体工作性态,提出了网片的两阶段恢复力模型、减压环的三阶段非线性模型以及支撑索的大位移滑移模拟方法,基于此,数值分析可再现被动柔性拦截网结构抵抗落石冲击的全过程行为。相关试验结果的比对验证了理论计算的正确性和有效性,为进一步拓展研究奠定了坚实理论基础。其三,揭示了柔性被动拦截网结构的三阶段运动变形模式。具体表现为：落石冲击后,钢丝绳网片的初始张紧阶段；网片大规模运动以及耗能系统的启动,系统整体的拦截滑移阶段；支撑结构的运动,耗能系统的全面启动,系统的整体偏摆阶段。每一个运动变形阶段,皆有相应的结构受力、传力特征与之匹配。其四,提出了被动柔性拦截网结构的自适应变张力结构属性的理论定义。该理论可完整描述柔性网结构的张力刚度在冲击过程中的变化特征：落石冲击接触前为弱张力状态,张力刚度仅维持初始形状：落石冲击发生后的一定时段为张力增长状态；耗能子系统启动后,为准定常张力状态；耗能系统启动完毕后再过渡到张力增长状态；最后为破断状态。据此提出了被动柔性拦截网结构的归一化性能曲线模型。最后,建立了基于能量匹配的工程设计方法。该套设计方法根据组成部件合理的能量匹配比例,针对每一种部件,采用理论解析,并结合结构力学以及材料力学,完成其耗能配置设计,形成了柔性被动拦截网结构的工程设计方法,实现了柔性被动拦截网结构的“可设计”与“简便设计”。试验数据和数值计算结果的证明了该方法的可靠性。
[Abstract]:In the past 30 years, China has become one of the most serious global geological disaster countries. For the large volume of rockfall, collapse and other geological disasters, scholars and engineers put forward the corresponding measures and methods, a variety of the flexible steel net is a kind of protective measures are widely used. However, the use of that flexible interception network system failure frequently appear in the actual project, intercept and failure, the reason is that the current domestic working mechanism of flexible steel net structure is unclear, the lack of effective control technology, and its structural behavior is very complicated, very few research results. Therefore, the flexible passive flexible steel net structure as the research object the test and analysis, the combination of theory, a theoretical calculation of the impact test method, and carries out research on the mechanical behavior and design methods, the main research contents and achievements The results are as follows: first, full-scale tests carried out passive flexible steel net structure. The impact resistance of rockfall intercepting network structure subjected to rockfall impact, the whole process of force, force, deformation and movement characteristics, based on high speed camera deconstruction, the deformation, the whole system motion, reveals the key the mechanical behavior of main component. Secondly, established the numerical passive flexible steel net structure calculation theory. Combined with the mechanical behavior experimental study of relevant data at home and abroad, and according to the working state of passive flexible steel net structure, put forward the restoring force model of two stage mesh, decompression ring three phase nonlinear model and the the supporting cable of large displacement slip simulation method, based on this, the numerical analysis of the whole process behavior can be reproduced passive flexible steel net structure. The resistance of rockfall impact test results to verify the theoretical ratio The correctness and validity of the calculation, and laid a solid theoretical foundation for the further research. Thirdly, to reveal the deformation model of three stage movement of the flexible passive intercept network structure. Specific performance: the impact of rockfall, steel wire mesh of the initial tensioning stages; mesh mass movement and energy dissipation system startup, intercept slip the stage of the entire system; supporting structure movement, launched a comprehensive energy consumption system, the whole system swing stage. Every movement and deformation stage, all has the corresponding force structure, force transmission characteristics and matching. Finally, puts forward the theoretical definition of adaptive passive flexible steel net structure variable tension structure properties. The theory can be a complete description of the structure of flexible tension stiffness variation in the impact process: rockfall impact before contact is a weak state of tension, tension stiffness only maintained the initial shape of rockfall impact: A certain period of time after the occurrence of the tension growth condition; start energy subsystem, as quasi steady state tension; energy dissipation system starts after the transition to increase tension state; finally breaking state. Put forward the normalized performance curve model of passive flexible steel net structure. Finally, the establishment of energy, engineering design the method based on the design method of the matching proportion according to the components of reasonable energy, for each component, by using theoretical analysis, combined with the structural mechanics and mechanics of materials, the energy configuration design, an engineering design method of flexible passive intercept network structure, realize flexible passive interception network structure of the "design" with the simple design. The experimental data and numerical results prove the reliability of the method.

【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU311;TU761.1

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