Experimental study on The Distortional Bucking of Ultimate Thin-Walled Open Section Member

本文介绍了为弄清超薄壁受压构件局部失稳和畸变失稳的基本性能而进行的板厚约为1.0mm的薄壁卷边槽钢短柱的受压试验结果，然后详细阐述了基于屈服线理论的数值分析方法。研究结果表明：（1）板的局部屈曲强度不仅受宽厚比的影响，还受相邻板的影响。特别是，凸缘强度受唇缘长度的强烈影响。ii）基于屈服线理论的分析很好地解释了试验中观察到的畸变屈曲引起的破坏行为，该分析使用了一个数学模型，其中唇缘被视为翼缘的一部分，并且实验最大强度也很好地解释了试验中观察到的畸变屈曲。 关于我们 其次，介绍了双卷边槽钢组合梁的负弯曲试验结果，以及可能的刚度和强度评估方法，并讨论了刚度、强度和破坏模式，将试验结果与分析结果进行了比较。研究结果表明：（1）同一试件发生了局部屈曲、翼缘畸变屈曲和腹板畸变屈曲三种屈曲形式，且三种屈曲形式的变形相互影响，但在侧向支撑间距较短的试件中，翼缘畸变屈曲变形占主导地位，而在侧向支撑间距较长的试件中，腹板畸变屈曲变形占主导地位。ii）随着卷边槽的高度变得更高，并且横向支撑间隔变得更长，畸变屈曲强度趋于变得更小。（3）考虑畸变屈曲影响的有限条法屈曲强度分析结果与试验结果吻合较好。少

A report has been presented to report findings obtained from the research supported by the Grant-in-Aid.The report first introduces the results of compression tests of light-gauge lipped channel short columns with plate thickness equal to about 1.0 mm that has been carried out to clarify the fundamental behavior of ultra thin-walled compression members failing in the local and distortional buckling, and then the method of numerical analysis based on the yield line theory is thoroughly explained. The research findings are as follows : i) Local buckling strength of a plate is affected by not only width-thickness ratio but also the behavior of adjacent plates. Especially, flange strength is strongly affected by lip length. ii) Failure behavior due to distortional buckling observed in the tests is well explained by the analysis based on the yield line theory using a mathematical model in which the lip is treated as a part of the flange, and the experimental maximum strength is also well es … More timated by the yield line analysis.Secondly, the report shows the results of negative bending tests of beams consisting of two lipped-channels, and the possible stiffness and strength evaluation methods, and then discusses stiffness, strength, and failure mode, comparing the results of tests and analysis. The research findings are as follows : i) Three kinds of buckling, local buckling, flange distortional buckling and web distortional buckling, occur in a specimen, and their deformations grows affecting each other, but the deformation of flange distortional buckling becomes predominant in the specimens with shorter lateral support interval, while that of web becomes predominant in the specimens with longer lateral support interval. ii) Distortional buckling strength tends to become smaller, as the height of the lipped channel becomes taller, and the lateral support interval becomes longer. iii) The buckling strength obtained by the analysis considering the effect of distortional buckling based on the finite strip method agrees well the experimental results. Less