冷弯薄壁C型构件的屈曲模态形成与变形相关作用

Buckling mode formation and related buckling mechanism of C-section specimens of cold-formed steel

采用有限元数值模拟方法,从一维杆件屈曲模态形成机理入手,推广至薄壁C型构件屈曲模态的形成,重点分析了几何初试缺陷与构件几何属性对构件屈曲模态的影响和相互作用,证明构件几何属性对构件最终破坏模态的决定作用.同时,考虑构件长度对畸变屈曲模态的形成和对承载力的影响,以此划分不同的屈曲区间;在此基础上,定义各类屈曲变形参数,进行相关屈曲作用机理和变形相关性的分析与推导,并结合试验现象加以验证;最后提出形心偏移的概念,对整体变形未引发整体失稳的现象加以解释,提出了新的屈曲判定准则,以此精确的判断构件的屈曲模态和屈曲过程.

The buckling mode of thin-walled C-section components tormation is obtained Irom the anaL- ysis on mechanism of one-dimensional bar buckling modes using the FEM and theoretical analysis. The influence on buckling mode of geometry defects and component properties, as well as the interaction between the two, are focused on, which tells that component section properties control the ultimately destroy modal. In addition, considering the influence of length on carrying capacity and the distortion- al buckling mode, various buckling range are divided. Based on that, parameters on various types of buckling deformation are defined for the analysis and derivation of related buckling, which are proved by the test. Lastly, the reason that overall deformation does not lead to the global buckling is explained by the centroid offset, and new judging criterion is proposed, which can show us the buckling mode and course accurately.