轴心受压复杂卷边等肢角钢屈曲承载力试验与设计方法研究

Study on Buckling Bearing Capacity Test and Design Method of Cold-Formed Thin-Walled Steel Double-Lipped Equal-Leg Angle under Axial Compression

为了研究轴心受压冷弯薄壁复杂卷边等肢角钢的屈曲性能及承载力设计方法.首先,对16根不同截面和不同长细比的复杂卷边等肢角钢开展轴压承载力试验.结果表明:宽厚比较小、长细比较小的试件发生畸变屈曲,而宽厚比较小、长细比较大的试件发生畸变和整体弯曲的相关屈曲;宽厚比较大、长细比较小的试件发生局部和畸变相关屈曲,而宽厚比较大、长细比较大的试件发生局部、畸变和整体弯曲相关屈曲.随后,采用ABAQUS有限元仿真软件对试验进行了模拟分析,屈曲模式和承载力分析结果与试验结果吻合良好,表明用构建的有限元模型分析此类冷弯薄壁复杂卷边等肢角钢的屈曲和承载力是可行的.最后,将试验结果与直接强度法和有效宽度法计算结果进行对比,表明直接强度法和有效宽度法计算承载力非常保守或偏不安全.基于上述研究结果,提出轴心受压冷弯薄壁复杂卷边等肢角钢柱承载力计算的修正直接强度法和有效宽度法,试验结果对比表明建议方法是较为精确且偏于安全的.

In order to study the buckling performance and bearing capacity design method of cold-formed thin-walled steel double-lipped equal-leg angle under axial compression,the axial compression capacity test of 16 complex crimped equal-limb angle steels with different sections and lengths was carried out.The results show that distortional buckling occurs to the specimens with small width-to-thickness ratio and small slenderness ratio,while the specimens with small width-to-thickness ratio and large slenderness ratio undergo distortional buckling and overall bending buckling.For the specimens with large width-to-thickness ratio and small slenderness ratio,local and distortion-related buckling occurs,while for the specimens with large width-to-thickness ratio and large slenderness ratio,local,distortion-related and overall bending-related buckling occurs.Subsequently,the ABAQUS finite element simulation software was used to simulate the test,and the buckling mode and bearing capacity analysis results were in good agreement with the test results,indicating that the finite element model was constructed to analyze the buckling and bearing capacity of this kind of cold-formed thin-walled complex lip angle steel.Finally,the test results were compared with the calculation results of the direct strength method and the effective width method,which shows that the direct strength method and the effective width method are very conservative or unsafe in calculating the bearing capacity.Based on the above research results,the modified direct strength method and the effective width method for calculating the bearing capacity of cold-formed thin-walled complex edged equal-leg angle steel columns under axial compression are proposed.The comparison of test results shows that the proposed method is more accurate and safer.