杆系结构鲁棒性应变能敏感度分析及试验

为研究结构鲁棒性动态分析方法,进行了理论分析、数值模拟和破坏性模型试验。结合平面悬臂桁架和六角星型穹顶算例,利用应变能敏感度法分析了杆系结构鲁棒性。基于杆件移除法讨论了结构应变能和应变能敏感度对结构破坏特征的影响,并同鲁棒性应力变化率评价法进行了对比。结果表明:应变能敏感度法能动态地反映杆系结构鲁棒性变化、预测结构稳定极限荷载、识别结构破坏模态及评价杆件易损性;尽管支座压杆、环向拉杆对应变能敏感度的影响比中心压杆小,但可能引起结构整体倾覆和中心压杆强度破坏;工程应用中应在杆件重要性分析和结构破坏模态识别基础上采用应变能敏感度法评价结构鲁棒性。

Experimental Research and Strain Energy Sensitivity Analysis Method on Robustness of Truss Structure

An important index for evaluating structural anti-progressive collapse capability is robustness. In order to study the dynamic analysis method of structural robustness, theoretical analysis, numerical simulation, and the destructive model test are conducted. Using samples of a planar cantilever truss and hexagonal star-type dome, the robustness of a truss structure is analyzed on the basis of the strain energy sensitivity method. The influences of structural strain energy and strain energy sensitivity on the structural destructive characteristic are discussed based on the element removal method, which is compared with the stress ratio evaluation method of structural robustness. The results show that the strain energy sensitivity method is effective in reflecting robustness changes of the truss structure, predicting the structural maximum stable bearing loading, recognizing the structural damage mode, and evaluating element vulnerability. Although supporting compression struts and circumferential tension struts have less influence on strain energy sensitivity compared with the radial direction compression bars, they will cause structural integral collapse and strength failure of central compressive struts. As a result, structural robustness evaluation can be achieved by the strain energy method based on analyzing the import coefficient of elements and recognizing the structural damage mode in engineering applications.