冷弯薄壁型钢四肢组合受弯构件承载力研究

针对冷弯薄壁型钢四肢组合箱形截面受弯构件,建立了考虑材料、几何和接触非线性的有限元模型,进行了其承载力的数值分析.数值分析所得构件的破坏模式、极限承载力和荷载-挠度曲线与试验结果吻合较好,验证了有限元模型的可靠性.采用这一模型就钉距、截面高度、宽度及初始缺陷等对构件极限承载力的影响进行了一系列参数分析.提出了构件实用设计和计算的折减系数法,与现有AISI和中国规范基于有效宽度法的计算结果进行了比较,证明现有规范计算结果偏于保守,本文方法与数值分析结果吻合较好、简便可行.

Analysis of the Bearing Capacity of Cold-formed Steel Quadruple Limbs Built-up Members under Flexural Loading

Specimens of cold-formed steel quadruple limbs built-up box section member were tested to investigate its load capacity under flexural loading, and a finite element model involving geometric large deformation, materials and contact nonlinearity was established for numerical analysis. The model was validated by comparing the failure mode, ultimate bearing capacity and load-deflection curves with the test result. Based on this proved model, a series of parametric analysis was carried out to identify factors affecting flexural strength, such as spacing of screws, the height and width of section, and the quantity of initial imperfections. A practical design method named reduction coefficient method based on effective width method was proposed and compared with current AISI and Chinese cold-formed steel codes. It shows that current AISI and Chinese codes lead to a conservative evaluation. The reduction coefficient method proposed in this paper shows good agreement with the finite element result, and is relatively simple and convenient for design.