Numerical and analytical investigation towards performance enhancement of a newly developed rockfall protective cable-net structure
Numerical and analytical investigation towards performance enhancement of a newly developed rockfall protective cable-net structure
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DOI：
10.5194/nhess-12-1135-2012
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发表时间：
2012-04
影响因子：
4.6
通讯作者：
S. Dhakal;N. Bhandary;R. Yatabe;N. Kinoshita
中科院分区：
文献类型：
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作者：
S. Dhakal;N. Bhandary;R. Yatabe;N. Kinoshita
抽象的。在之前的一篇配套论文中，我们提出了日本新开发的一种特殊类型的落石防护索网结构（屏障）的三层模型。其中，我们开发了一个基于有限元的三维非线性数值模型，并通过单元和结构级物理测试进行了校准/反计算和验证。此外，使用非常简单的集中质量、单自由度、等效线性解析模型，基于数值模型测试的反分析，通过修改结合线性动量和能量守恒原理获得的基本方程，设计了全局位移预测相关性。在本文中，我们使用开发的模型来探索结构在以下方面的性能增强潜力：(a) 全局位移的控制——由于目标地点可用的空间狭窄，这可能是拟议结构的主要性能标准；(b) 现有 U 型螺栓型摩擦制动装置的能量耗散增加——被认为在集成到结构中时性能较弱。一组参数研究揭示了实现结构质量第一个目标的相关性，特别是通过操纵线网的特性，并且还揭示了冲击块参数的影响。为了实现第二个目标，另一组参数研究提出了对所研究的制动装置（耗能器）的本构行为（模型）进行一些创新性改进的建议，此外还提出了根据已识别的潜在缺陷仔细处理该装置的重要建议。
Abstract. In a previous companion paper, we presented a three-tier modelling of a particular type of rockfall protective cable-net structure (barrier), developed newly in Japan. Therein, we developed a three-dimensional, Finite Element based, nonlinear numerical model having been calibrated/back-calculated and verified with the element- and structure-level physical tests. Moreover, using a very simple, lumped-mass, single-degree-of-freedom, equivalently linear analytical model, a global-displacement-predictive correlation was devised by modifying the basic equation – obtained by combining the principles of conservation of linear momentum and energy – based on the back-analysis of the tests on the numerical model. In this paper, we use the developed models to explore the performance enhancement potential of the structure in terms of (a) the control of global displacement – possibly the major performance criterion for the proposed structure owing to a narrow space available in the targeted site, and (b) the increase in energy dissipation by the existing U-bolt-type Friction-brake Devices – which are identified to have performed weakly when integrated into the structure. A set of parametric investigations have revealed correlations to achieve the first objective in terms of the structure's mass, particularly by manipulating the wire-net's characteristics, and has additionally disclosed the effects of the impacting-block's parameters. Towards achieving the second objective, another set of parametric investigations have led to a proposal of a few innovative improvements in the constitutive behaviour (model) of the studied brake device (dissipator), in addition to an important recommendation of careful handling of the device based on the identified potential flaw.