基于塑性极限状态的结构易损性分析

Structural vulnerability analysis based on plastic limit state

摘要:

为揭示结构体系存在的弱点,研究局部损伤的敏感性对结构性能的影响,提出基于塑性极限分析的结构易损性分析方法,以桁架结构为对象,将结构极限承载能力作为结构性能参数,利用机构生成方法得到结构体系的极限荷载乘子及相应的失效模式.在给定结构性能需求的前提下,可以根据极限荷载乘子随不同损伤场景的损伤程度变化,得到特定荷载模式下的最易损损伤场景.算例分析结果表明:结构性能随构件损伤程度的加大而降低;由于结构拓扑构成的变化以及内力重分配的影响,结构主导失效模式因构件破坏程度的不同而改变.失效模式中所涉及的构件都是影响结构性能的关键构件,因此可以为结构的设计、监测与维护提供参考.

Abstract:

To reveal the weakness of structural system by studying structural performance susceptibility to local damage,a method of structural vulnerability analysis based on the plastic limit theory is proposed,and based on the mechanism generation method,the ultimate loading factor and the corresponding failure mode of a truss structural system are analyzed.The ultimate loading factor is then used to measure the performance of the structural system.By contrasting different damage scenarios under specified structural performance requirement,the most vulnerable damage scenario can be obtained according to the variation of ultimate loading factor to the severity of damage.The results of the case study show that the structural performance degenerates with the damage severity,and the dominative failure mode also changes with the damage severity due to the variation of structural topology composition and the redistribution of structural internal force.All the components related to a certain failure mode are the key components which serve as the most influential part to the structural performance.Therefore the analytical results can be as a reference for the structural design,monitoring and maintenance.