腹板开圆孔冷弯卷边槽钢轴压构件畸变屈曲承载力试验及计算方法

DISTORTIONAL BUCKLING TEST AND CALCULATION METHOD OF LOAD-CARRYING CAPACITY OF COLD-FORMED THIN-WALLED STEEL LIPPED CHANNEL COLUMNS WITH CIRCLE HOLES IN WEB UNDER AXIAL COMPRESSION

对26根屈服强度为235 MPa的腹板开孔和未开孔冷弯薄壁型钢截面轴压构件进行畸变屈曲承载力试验研究,分析构件的屈曲模式和极限承载力。将我国及北美相关规范计算的构件承载力以及非线性有限元数值模拟结果与试验结果进行分析比较,并对腹板开孔冷弯薄壁型钢截面轴压构件的承载力合理计算模式进行研究。结果表明:对于中等长度腹板开孔冷弯薄壁型钢截面轴压构件主要出现局部、畸变和整体屈曲的相关作用;腹板开孔对构件畸变屈曲稳定承载力有一定的降低作用;采用折减构件有效截面面积的修正方法可计算开孔构件的畸变屈曲稳定承载力;非线性有限元方法可用于腹板开孔冷弯薄壁型钢构件的屈曲模式和极限承载力的分析。

In order to research the distortional buckling mode and load-carrying capacity of cold-formed thin-walled steel members with holes,compression tests were conducted on 26 intermediate length columns with and without web holes. For each specimen,a shell finite element eigenbuckling analysis and nonlinear analysis were also conducted such that the influence of the hole on local,distortional,and global elastic buckling responses could also be got. The comparison of ultimate strength between test results and calculated results using relevant codes was made. The calculated method for cold-formed thin-walled steel columns with web holes was proposed. The results showed that the interaction of local buckling,distortional buckling,and overall buckling usually would occur in the intermediate length member under axial compression,and the web holes had a little influence on the elastic buckling strength and the distortional buckling ultimate strength of columns,the ultimate strength of the members with holes in web could be predicted using a reduced effective area,and the nonlinear finite element method could be used to analyse the buckling mode and ultimate strength of cold-formed steel members with holes in web.