(浙江省建筑设计研究院, 杭州 310006)

摘要: 对于荷载无偏心、构件无初弯曲和初转角、无残余应力等初始缺陷的完善梁,其整体失稳属于极值型失稳。但对于实际结构,由于初始缺陷的存在,一经加载即出现侧向位移和截面转角,失稳时的极限弯矩要小于完善梁的临界弯矩。 为了较为真实地对实际结构进行有限元模拟分析,有必要考虑初始缺陷。 着重考虑初始几何缺陷和残余应力这两种初始缺陷,并分别研究这两种初始缺陷在 ANSYS 有限元分析软件中的模拟方法,将模拟分析结果与试验结果进行对比,并对仅考虑初始几何缺陷和同时考虑两种初始缺陷这两种缺陷情况进行对比。 结果表明,模拟分析结果与试验结果有较好的吻合度;残余应力的存在会使钢梁更快地产生水平位移,整体稳定临界荷载也有一定程度的下降,钢梁跨高比越大,下降程度越大。

关键词: 钢梁稳定; 初始几何缺陷; 残余应力; 极限弯矩; 临界弯矩

中图分类号:TU317+. 1 文献标志码:A 文章编号:1002-848X(2022)15-0075-05

DOI:10. 1970 / j. jzjg. ZIAD2230

Simulation study of initial defects in analysis of overall stability of steel beams

ZHANG Heping, CHEN Xiating

( Zhejiang Province Institute of Architectural Design and Research, Hangzhou 310006, China)

Abstract: For perfect beams without load eccentricity, initial bending, initial angles and residual stresses, the overallinstability belongs to the extreme-value type instability. However, for the actual structure, due to the existence of initialdefects, there is a lateral displacement and cross-section angle once loaded, and the ultimate bending moment at instabilityis smaller than the critical bending moment of the perfect beam. In order to perform a realistic finite element simulationanalysis on a practical structure, it is necessary to consider the initial defects. The initial defects of initial geometric defectsand residual stresses were considered in particular, and the simulation methods of the two initial defects in finite elementanalysis software ANSYS were studied, and the simulation analysis results were compared with the experimental results,and the two types of defects considering only the initial geometric defects and considering both initial defects werecompared. The results show that the simulation analysis results are in good agreement with the test results; the existence ofresidual stress causes the steel beam to generate horizontal displacement faster, and the overall stable critical load alsodecreases to a certain extent. The greater the span-to-height ratio of the steel beam is, the greater the decrease degree is.

Keywords:steel beam stability; initial geometric defect; residual stress; ultimate bending moment; critical bendingmoment

第一作者:张和平,硕士,高级工程师,一级注 册 结 构 工 程 师,主 要 从 事 大 跨 空 间 结 构、钢 结 构、超 高 层 结 构 等 研 究,Email:zhangheping@ ziad. cn。

[引用本文] 张和平,陈夏挺. 钢梁整体稳定有限元分析中初始缺陷模拟研究[ J] . 建筑结构,2022,52( 15) :75-79.ZHANG Heping,CHEN Xiating. Simulation study of initial defects in analysis of overall stability of steel beams [ J ] .Building Structure,2022,52(15) :75-79.