初始缺陷对冷弯薄壁腹板开孔C形钢梁稳定承载力的影响研究
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（1 中国建筑设计研究院，北京 100044； 2 清华大学土木工程系，北京 100084）[摘要] 冷弯薄壁型钢构件在制作安装过程中将会产生一定的初始缺陷，包括几何初始缺陷和力学初始缺陷。采用ANSYS程序分析了几何初始缺陷、冷弯残余应力及两者综合作用对冷弯薄壁腹板开孔C形钢梁稳定承载性能的影响。根据算例分析得到以下结论和建议：对于破坏形式为跨中截面受弯破坏的开孔梁，局部初始缺陷对其承载力几乎没有影响，可忽略局部初始缺陷的影响；对于破坏形式为局部屈曲破坏的开孔梁，需要考虑局部初始缺陷的影响，可取0.005倍的腹板高度作为初始缺陷峰值进行计算。冷弯残余应力对构件极限承载力影响较小，使构件整体刚度和稳定性略有降低。[关键词] 冷弯薄壁型钢; 腹板开孔; C 形截面梁; 稳定承载力; 初始缺陷; 残余应力中图分类号：TU391 文献标识码： 文章编号：1002-848X(2013)S1-0439-04Study on the effects of initial imperfections on stability bearing capacity of the web opening C-shaped cold-formed steel beamXu Hongyan1,2, Liu Jingbo2(1 Structure Institute, China Architecture Design & Research Group, Beijing 100044, China;2 Department of Civil Engineering, Tsinghua University, Beijing 100084, China)Abstract: C-shaped cold-formed steel beam will carry some initial imperfections during manufacturing process, including initial geometrical imperfection and cold-formed residual stress. Finite element analysis software ANSYS is used to study the influence of initial geometrical imperfection and cold-formed residual stress in bearing capacity of the web opening beam. According to the results, the following conclusion and propose are given: the initial geometrical imperfection should be included only when the failure mode is local buckling, and a peak value of the initial geometrical imperfection is suggested as 0.005 times the web height. Meanwhile, stability bearing capacity is verified to be little influenced by the cold-formed residual stress.Keywords: cold-formed steel; slot in web plate; beam with C-shaped section; stability bearing capacity; initial imperfection; residual stress
