基于改进应力变化率法的空间杆系结构鲁棒性分析  

Robustness analysis of spatial truss structures with an improved stress rate method

作　　者：刘国光[1] 武志玮[1] 刘慧源[1] 谭振[1] 

机构地区：[1]中国民航大学机场学院,天津300300

出　　处：《振动与冲击》2014年第18期77-83,共7页Journal of Vibration and Shock

基　　金：国家自然基金项目(51178456);民航局民航科技资助项目(MHRD201230);中央高校基本业务费中国民航大学专项资助(3122013D010);中国民航大学青年骨干教育项目

摘　　要：为研究空间杆系结构鲁棒性及结构失效模式预测方法,将杆件关键系数引入应力变化率法用于结构失效模式预测和结构可靠度分析以考虑悬链线作用对杆件失效模式的影响。利用ANSYS数值模拟分析了静力阶跃荷载和竖向地震荷载作用下单层星型穹顶结构杆件失效模式,对比了考虑杆件关键系数前后应力变化率曲线。作为对比分析,应用有限元软件ALGOR分析了一种新型张弦桁架结构在7种局部构件损坏工况下剩余构件内力变化的敏感性系数,分析了结构可靠度的鲁棒性并同传统张弦桁架结构进行了对比。结果表明,考虑杆件关键系数后显著提高了临界破坏发生前若干荷载步的应力变化率,从而可利用该方法在结构失效前进行预警。通过改变下弦拉索的数量和布置方式可有效降低其对构件内力变化敏感性的影响,从而有效提高结构可靠度。在断索工况下,该高冗余度张弦桁架结构可提高结构抗连续性倒塌能力,延长结构从局部破坏到全部倒塌的过程,增加了结构安全储备,增强了结构抵抗灾变荷载的能力。In order to study the robustness of spatial truss structures and the prediction method of structural failure models, the member key coefficien was introduced into the stress rate method considering structural catenary curve effects on element＇s failure models to predict structural failure models and to analyze structural reliability. A single layer star dome＇s structural failure model was analyzed using ANSYS and comparing the curves of stress rate with the classical and improved stress rate methods under static step load and vertical seismic loads. As a contrast analysis, the finite element analysis software ALGOR was applied to analyze a new type of truss string structure, its structural sensitivity coefficient was computed under 7 partial failure conditions, the structural robustness was analyzed and compared with that of a traditional truss string structure. The results showed that the stress rate before the structural critical failure significantly increases after considering the member key coefficient, so this method can be used to predict structural failure; by changing the numbers and location arrangement of cables, the structural failure sensitivity is significantly reduced and the structural reliability is greatly improved; under broken cable conditions, the resisting ability against progressive collapse of the new type truss string structure is improved and the process from partial damage to full collapse is prolonged, the structure safety is improved and the structural capability to resist disaster loads is enhanced.

关 键 词：鲁棒性 应力变化率法 空间杆系结构 失效模式预测 

分 类 号：TU394[建筑科学—结构工程]