轴心受压钢构件高温下局部稳定设计方法

为了得到钢构件高温下局部稳定设计方法,通过试验对建立的有限元模型进行了验证。采用验证后的有限元模型,分析了温度、板件宽厚比、初始几何缺陷、腹板和翼缘相互作用等因素对H形截面轴心受压钢构件局部屈曲应力的影响,提出了Q235钢和Q460钢H形截面轴心受压构件高温下的局部稳定承载力简化计算公式和高温下防止局部屈曲的翼缘宽厚比和腹板高厚比限值。研究表明:当板件宽厚比较小时,构件的局部屈曲应力随宽厚比的增大迅速减小,宽厚比较大时,构件屈曲应力降低不明显;初始几何缺陷对构件局部屈曲应力影响较小;高温下翼缘对腹板屈曲的约束作用比常温下明显;高温下防止局部屈曲的宽厚比限值与常温下宽厚比限值不同。

Design approach for local stability ofaxially compressed steel members at elevated temperature

In order to obtain the design approach for local buckling of steel members at elevated temperatures, an established finite element model is verified by experiment. The calibrated model is used to study the effect of temperature, width to thickness ratio, initial imperfection and interaction between web and flange on the local buckling stress of H shaped axially compressed members. Simplified design approach and limited ratio of width to thickness is proposed on Q235 steel and Q460 steel H shaped axially compressed members at elevated temperature.The study shows that the local buckling stress decreases rapidly with the increase of width to thickness ratio, and the ultimate stress decreases slowly when width to thickness ratio is large enough.The influence of initial imperfection on local buckling stress is insignificant. Restrained effect of the flange on the web at elevated temperature is more obvious than that at room temperature; and the limited ratio of width to thickness at elevated temperature is different with that at room temperature.