冷弯薄壁型钢拼合工字形截面柱畸变屈曲及相关屈曲轴压性能试验与直接强度法研究  

Tests and Direct Strength Method on the Distortional Buckling and Interactive Buckling of Cold-Formed Thin-Walled Steel Built-Up I-section Columns Under Axial Compression

作　　者：姚行友[1,2] 李潇 YAO Xingyou;LI Xiao(School of Architecture and Civil Engineering,Nanchang Institute of Technology,Nanchang 330099,China;Jiangxi Province Key Laboratory of Hydraulic and Civil Engineering Infrastructure Security,Nanchang Institute of Technology,Nanchang 330099,China)

机构地区：[1]南昌工程学院土木与建筑工程学院,南昌330099 [2]南昌工程学院江西省水利土木工程基础设施安全重点实验室,南昌330099

出　　处：《建筑钢结构进展》2021年第12期33-46,共14页Progress in Steel Building Structures

基　　金：国家自然科学基金(51868049);江西省自然科学基金(20181BAB206040);江西省教育厅科学技术研究项目(GJJ180932、GJJ170983)。

摘　　要：为了研究冷弯薄壁型钢拼合工字形截面柱畸变屈曲及相关屈曲性能和完善直接强度法,对56根不同横截面和长细比的LG550冷弯薄壁型钢拼合工字形截面柱进行了轴压试验。试验结果表明:拼合工字形截面轴压试件表现为畸变和局部相关屈曲以及畸变、局部和整体相关屈曲两种破坏模式。对于发生畸变和局部相关屈曲试件,长细比对其承载力影响较小;但对于板件宽厚比相对较小、长细比较大发生畸变、局部和整体相关屈曲的试件,其极限承载力和刚度随长细比的增大逐渐降低。螺钉间距和端部螺钉群对其承载力影响较小。螺钉连接可满足各肢协同工作要求。采用ABAQUS有限元程序对试验进行了模拟,模拟结果与试验结果吻合良好,验证了有限元分析此类拼合试件的可行性。进而采用验证的有限元模型对该类拼合柱轴压性能的影响因素(长细比、螺钉间距、端部螺钉群)进行分析,结果表明长细比对拼合工字形截面柱轴压性能影响较大;螺钉间距小于450 mm后对承载力影响较小;端部螺钉群对短柱影响较小,对长柱有一定的影响;当拼合柱螺钉间距较大时,端部螺钉群对其承载力影响较大。最后提出了冷弯薄壁型钢拼合工字形截面柱的直接强度法修正公式,并利用试验结果验证了其准确性和可行性。In order to investigate the distortional buckling and interactive buckling behavior of the cold-formed thin-walled steel built-up I-section column and to develop the direct strength method, 56 cold-formed thin-walled steel built-up I-section columns with different cross-sections and slenderness ratio are tested under axial compression.The test results show that the failure modes of built-up I-section columns are the interaction of distortional buckling and local buckling and the interaction of distortional buckling, local buckling, and global buckling.The slenderness ratio has little effect on the ultimate strength of the built-up I-section columns which failed under the interaction of distortional buckling and local buckling.However, for the specimens failed with the interaction of distortional, local, and global buckling, which have smaller width-to-thickness ratio and larger slenderness ratio, the ultimate strength and stiffness decrease with the increasing of slenderness ratio.The spacing of screws and the end fastener group has little effect on the load carrying capacities.The screw can keep the two limbs of built-up I-section columns work together.The tests are simulated using the finite element software ABAQUS,and the simulation results show a good agreement with the test data and demonstrate the feasibility of using the finite element method to analyze these specimens.Furthermore, the finite element model is used to conduct parameter studies including slenderness ratio, spacing of screws and the end fastener group.The analysis results show that the slenderness ratio has a significant effect on the ultimate strength.The spacing of screws has little effect when it is less than 450 mm.The end fastener group has little effect for stud columns, but it has a significant influence when the spacing of screws is 450 mm.Finally, the modified direct strength method to calculate the load capacities of the cold-formed thin-walled built-up I-section columns under axial compression is presented, and the accuracy and fea

关 键 词：冷弯薄壁型钢 拼合工字形截面 轴压试件 畸变屈曲 相关屈曲 直接强度法 

分 类 号：TU392.1[建筑科学—结构工程]