基于增量动力分析方法的单层球壳结构强震损伤分析

为研究地震作用下空间网格结构的倒塌过程及其破坏行为,进而揭示结构的倒塌机理,基于增量动力分析方法(dynamic analysis method, IDA),以单层球面网壳结构为研究对象,考虑材料损伤累积效应,模拟网壳结构在地震作用下的倒塌过程,并分析不同杆件截面尺寸、矢跨比、初始几何缺陷、支座约束数量等参数对结构抗倒塌能力的影响。结果表明:强震作用下,考虑损伤后网壳结构的动力极限承载力比未考虑损伤时其极限承载力下降了20%左右,塑性单元比例上升10%左右;其他参数一定时,加强杆件截面以及矢跨比的减小,均能提高网壳的动力极限承载力,网壳对初始几何缺陷十分敏感,缺陷为跨度的1/100时其极限承载力比完整结构降低30%左右,支座约束减半后,损伤累积效应使结构的地震承载力降低10%左右。因此在结构设计之初,应考虑材料损伤累积效应的影响。

Analysis of strong earthquake damage of single-layer spherical shell structure based on IDA

In order to study the collapse process and failure behavior of space grid structure under earthquake action, and reveal the collapse mechanism of the structure, based on the incremental dynamic analysis method (IDA), the single-layer spherical reticulated shell structure is taken as the research object, and the cumulative effect of material damage is considered. The collapse process of the simulated reticulated shell structure under earthquake action is analyzed, and the influences of parameters such as cross-section size, span-to-span ratio, initial geometric imperfections, and number of bearing constraints on the collapse resistance of the structure are analyzed. The results show that under the action of strong earthquakes, considering the dynamic ultimate bearing capacity of the reticulated shell structure after damage, the ultimate bearing capacity of the reticulated shell structure is reduced by about 20%, and the proportion of plastic elements is increased by about 10%. When other parameters are constant, the reinforcing rods are strengthened. The reduction of the section and the span ratio can improve the dynamic ultimate bearing capacity of the reticulated shell. The reticulated shell is very sensitive to the initial geometrical defects. When the defect is 1/100 of the span, its ultimate bearing capacity is reduced by about 30% compared with the complete structure. After the bearing restraint is halved, the cumulative effect of the damage reduces the seismic bearing capacity of the structure by about 10%. Therefore, at the beginning of structural design, the effects of cumulative effects of material damage should be considered.