基于损伤场景的桁架结构拓扑易损性分析

Damage Scenarios Based Topological Vulnerability Analysis of Truss Structures

摘要:

重要工程结构可能因恐怖袭击等突发事件受到严重破坏，结构易损性分析是改进结构设计以提高结构安全储备的有效理论方法之一。结构拓扑易损性分析从影响结构易损性的内因揭示了结构体系中与外部荷载作用特性无关的先天弱点所在。分析中以结构的几何稳定性作为结构性能需求，采用了矩阵分析方法。以平面和空间桁架结构体系为例，探讨了结构中冗余构件配置的有效性以及不同易损场景对结构性能的影响程度。研究发现，合理的冗余构件分布能够将结构的易损场景限定在更小的范围内，而盲目增加冗余构件则不一定能起到降低结构易损性的作用；由于局部机构的存在，不同易损场景的影响范围不同。拓扑易损性分析可以把握结构体系的弱点所在，从而可采取有针对性的措施降低结构易损性。

Abstract:

Important structures may be fatally damaged by extreme events such as terrorist attack. Structural vulnerability analysis is becoming one of efficient theoretical methods to improve structural design, so as to increase structural safety. Structural topological vulnerability analysis can reveal the inherent structural weakness which is irrelevant to the external load by focusing on the internal factor of structural vulnerability. The matrix analysis method was used to study the structure geometrical stability which is a measurement of structural performance. A 2-D and a 3-D truss structures were used to study the effectiveness of the allocation of redundant components in structures, as well as the impact extent of different vulnerable scenarios to structural performance. It is found that the reasonable allocation of the redundant components may limit the vulnerable scenario to a relatively small region, whereas blindly increasing component redundancy may not serve any purpose to reduce the structural vulnerability; furthermore, due to the existence of local mechanisms, the event impact to the structural system is different for various vulnerable scenarios. With the help of topological vulnerability analysis, measures can be taken to reduce the structural vulnerability.