摘要
现阶段对结构鲁棒性设计并没有形成统一的理论和方法,而结构易损性分析能够有效揭示结构缺乏鲁棒性的内在原因。首先以双杆体系为例,将节点构形度和荷载作用下的节点位移随双杆夹角的变化规律进行比较,发现节点构形度的大小代表着结构在此节点处抵抗任意方向荷载的能力,证明了构形度为整个结构或子结构构形好坏的评价指标。其次,基于构形度等凝聚准则,通过凝聚过程建立结构拓扑关系层级模型,识别结构存在连接薄弱的部位,并通过对层级模型的拆解及破坏模式评价指标的计算,得到结构具有易损性的破坏模式,其中包括最小破坏模式、最易发生破坏模式、完全破坏模式及最大破坏模式共四种破坏模式。最后,针对上述过程编制C++程序予以实现,并将其应用到平面桁架、平面刚架及空间网壳结构的分析中。算例分析表明,结构构形易损性分析能够有效反应结构存在的薄弱部位,同时能够识别结构损伤与失效后果具有不成比例的破坏模式,为采取合理措施降低结构内在易损性提供理论依据。
There is no unified theory and method of structural robustness at present, however, a structural vulnerability analysis can effectively reveal intrinsic causes for lack of robustness. Firstly, taking a double-pole structure as an example, the change laws of the well-formedness of joint and nodal displacement under loads were analyzed and compared with the changes of the angle between two bars. It was concluded that the well-formedness of a joint represents the ability of the structure to resist loads along any arbitrary direction; thus, the well-formedness is confirmed to be an evaluation indicator of configuration of a whole structure or its sub-structures. Secondly, on the basis of clustering criteria of well-formedness etc., a structural hierarchical model could be established through a clustering process. Thus, the weakness of the structure could be identified. Furthermore, four kinds of vulnerability failure scenarios were obtained through unzipping process and calculation of indexes of failure scenarios. They were minimum failure scenario, minimum damage demand one, total failure one and maximum failure one. Finally, a computer program was coded to perform above processes with C ＋ ＋ building language and was employed to analyze a planar truss, a planar frame and a reticulated shell. The results showed that the vulnerability analysis based on configuration can reflect the weak parts of a structure effectively and identify vulnerable failure scenarios with disproportionate structural damage to failure consequences. The above results provided a theoretical foundation for taking measures to reduce inherent vulnerability of structures
出处
《振动与冲击》
EI
CSCD
北大核心
2012年第17期67-80,共14页
Journal of Vibration and Shock
基金
国家自然科学基金重大研究计划培育项目(90715005)
教育部新世纪优秀人才支持计划(NCET-07-0186)
教育部博士点基金(200802860007)
关键词
杆系结构
构形易损性理论
破坏模式分析
member structures
form vulnerability theory
failure scenarios analysis
