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初始缺陷是影响大跨度结构稳定承载力和弹塑性抗震性能的重要因素,但杆件的初弯曲还较少考虑.为引入初弯曲并有效模拟杆件的弹塑性大变形反应,对圆钢管杆件的梁单元合理分段问题进行了考察.分析结果表明,当杆件划分4个三节点梁单元且端部与中部单元长度比值为1∶4时,便能确保与壳单元模型的弹塑性分析结果非常接近.以一经过满应力设计的弦支穹顶为研究对象,进行结构的弹塑性屈曲分析以及地震时程分析,考察杆件的初弯曲对结构稳定承载力以及地震响应的影响.发现考虑了梁单元细分并引入1/1000的杆件初弯曲后结构的极限承载力最多可降低13%.当地震动强度较大时,结构的顶点位移、塑性应变能等地震响应会随着杆件初弯曲的形状、方向和幅值的变化产生较大差异.
The initial defect is an important factor affecting the long-span structural stability and elasto-plastic seismic performance, but the initial bending of the members is seldom considered.In order to introduce the primary bending and effectively simulate the elastic-plastic deformation of the members, The analysis results show that when the members are divided into four three-node beam elements and the ratio of the end to the central element length is 1: 4, the elastic-plastic properties of the shell element model can be ensured. The results of the analysis are very close to each other.With a full-stress design of the suspen-dome as the research object, the elastoplastic buckling analysis and seismic time history analysis of the structure are carried out to investigate the influence of the initial bending of the member on the structural stability and seismic response. Considering the subdivision of the beam element and the introduction of 1 / 1000th member, the ultimate bearing capacity of the structure can be reduced by at most 13% .When the local vibration intensity is large, the seismic response of the structure such as apex displacement, The shape, orientation and amplitude of the initial bend have a big difference.