The School of Civil Engineering，Chongqing University
The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan)
钢结构发生局部屈曲破坏时，屈曲应力小于钢材的屈服强度。为了研究高温下高强Q690钢柱的局部稳定性能，本文采用ABAQUS有限元软件建立经试验验证的有限元模型，考虑宽厚比、温度、初始缺陷、残余应力和翼缘与腹板之间的相互作用的影响，对高强Q690钢柱进行参数分析。研究结果表明:宽厚比对局部屈曲有显著影响，宽厚比的增大导致试件极限承载力的降低；初始缺陷和残余应力对局部屈曲应力有较大影响，并且随着温度的升高，试件的极限承载力明显下降。将有限元分析结果与GB50017-2017、Eurocode 3和ANSI /AISC 360-10中的设计方法进行比较，提出了适用于高强Q690钢柱高温下的局部稳定设计方法和宽厚比限值
Local buckling is referred to the failure of a structural steel member and characterized by lower compressive stress than the corresponding stress that steel material can withstand. This paper highlights the effects of local buckling on the structural behavior of steel column subjected to elevated temperature. The aim of this paper is to develop a design method for the local buckling of high-strength (HSS) Q690 steel column at elevated temperature. Therefore, the local buckling of HSS Q690 steel columns is numerically investigated by the means of FE modeling using ABAQUS software. The developed FE models are validated against the experimental results of local buckling for HSS Q690 steel column under axial compression, which previously conducted by other researchers. Subsequently, a parametric study carried out to evaluate the influence of several parameters that affect the design of local buckling such as, the width-to-thickness ratio, temperature, initial imperfection, residual stress and interaction between the flange and web of the H-shaped cross-section. The results of study showed that local buckling is significantly affected by the width-to-thickness ratio in which increasing the width-to-thickness led to a reduction in the ultimate bearing capacity of the specimens. It also indicated that both initial imperfection and residual stress have a significant effect on local buckling stress. Furthermore, it was observed that the overall capacity of the specimens deteriorates significantly at elevated temperature as the temperature increases. Based on the results, simplified design method and new width-to-thickness ratio limits are proposed for the HSS Q690 steel compression members with H-section. The results data were also compared with the design rules provided by GB 50017-2017, Eurocode 3, and ANSI /AISC 360-10.