摘要
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.
Initial imperfection is one of the important factors affecting the buckling load capacity and elasto- plastic seismic response of large span structures. But the initial curvature of bar was seldom considered. In order to simulate the elasto-plastic and large deformed response of members with initial curvature effectively, a study was performed to find out the reasonable meshing method for beam element in circular tube. It showed that when the bar was divided into 4 three-node beam elements and the ratio of the length of the end part to the central part is 1 ： 4, the calculation would yield a result approximately to that of the model using shell element in elasto-plastic analysis. In order to find out the effect of member initial curvature on buckling capacity and seismic response, elasto-plastic buckling analysis and time-history analysis were performed on a suspended dome designed according to the full-stress principle. It reveals that when bar is meshed and the initial curvature with 1/1000 is introduced, the ultimate capacity of structure will decrease up to 13~. In case of the larger intensity of the earthquake, the seismic response of the structure, e.g. the displacement of the peak point of structure and plastic strain energy etc. , will vary greatly according to the shape, direction and peak value of initial curvature.
出处
《空间结构》
CSCD
北大核心
2013年第4期18-24,33,共8页
Spatial Structures
关键词
弦支穹顶
杆件初弯曲
稳定承载力
弹塑性
地震响应
suspended dome
bar initial curvature
buckling load capacity
elasto-plastic
earthquake respons
