基于直接强度法的冷弯薄壁开口多次卷边槽钢立柱截面形式研究

Research on cross-sections of cold-formed multi-roll lipped channel column based on DSM

现有组装式货架结构的冷弯薄壁开口多卷边柱截面较复杂,加劲高度、侧边高度、斜卷边坡角等参数的变化均对截面加工成形的精度有较大影响。本文基于直接强度法,结合参数化有限元分析,对比研究多卷边柱截面的有限元及使用中国规范、北美规范的计算结果。研究结果表明:对于冷弯薄壁开口多卷边柱,短柱失稳以畸变屈曲为主、辅以局部屈曲,长柱失稳以弯扭失稳为主;对于短柱及中长柱,有限元分析结果与两种规范均吻合良好,长柱则不够理想,相对于有限元结果,中国规范计算值偏低22.9%,北美规范计算值偏低17.0%,两种规范计算值均偏保守,此结果可以为该类截面规范公式修订提供参考。综合考虑截面性能及工艺要求,提出了一种与原有截面S0相比既能提高加工精度又能提高稳定承载力的截面形式S4。

The cross-sections of multi-roll lipped cold-formed steel column in steel storage racks are complicated due to many parameters, such as the depth of stiffening rib, the side width and the angle of slope, which have a great influence on the section forming precision. In this paper, based on the parametric finite element method, a comparative analysis is carried out to the results obtained from ABAQUS, GB50018 and AISI S100, trying to achieve a proper optimized section which the machining accuracy of the column could be enhanced without weakening its bearing capacity. The results show that for cold-formed multi-roll lipped channel column, distortional buckling mainly appears in the failure mode of short axial compression columns along with local buckling, while flexural-torsional buckling appears in the case of long columns. For short and middle long columns, the finite element analysis have a great agreement with the results calculated by codes. However, for long columns, results calculated by GB50018 are 22.9% lower than the finite element analysis, and results calculated by AISI S100 are 17.0% lower. Thus results calculated by codes are overly conservative compared to the finite element analysis. This result can provide a reference for the revision of the standard formula of this kind of section. An appropriate section form, S4, is proposed, according to the production requirement and the analysis of the results.