960MPa高强度钢材轴压柱局部稳定性能及设计方法

为研究960 MPa(屈服强度标准值)高强度钢材轴心受压构件的局部稳定受力性能,本文使用ANSYS软件建立有限元模型,对4个箱形截面和4个工字形截面轴心受压构件进行了有限元分析.模型考虑了几何初始缺陷及焊接残余应力的影响,提取构件的极限承载力和局部屈曲临界承载力的有限元计算结果与试验实测结果进行对比,验证了模型的有效性.利用这种建模方法,对960 MPa高强度钢材箱形和工字形轴心受压构件的局部稳定受力性能进行了有限元参数分析,并将有限元计算结果,以及本文汇总的已有试验结果,与中国、美国和欧洲的钢结构设计规范中轴心受压构件的设计曲线进行了对比,并提出了新的设计公式.结果表明,本文使用的有限元建模方法能够准确地分析计算960 MPa高强度钢材轴心受压构件的局部屈曲受力性能;几何初始缺陷和残余应力对构件的极限应力的影响很小,但是对板件宽厚比较大构件的局部屈曲应力的影响相对较大;相对于中美欧现行钢结构设计规范中的设计方法,本文提出的设计公式更适用于960 MPa高强度钢材轴心受压构件的局部屈曲应力和屈曲后极限应力的设计计算.

Analysis and Design Method on Local Buckling Behavior of 960 MPa High Strength Steel Columns under Axial Compression

In order to examine the local buckling behavior of 960 MPa (yield strength standard) high strength steel (HSS) columns under axial compression, finite element models were developed by using the finite element (FE) software, ANSYS. Local buckling of four welded box section and four welded I-section columns under axial compression considering the initial geometric imperfections and welding-induced residual stresses was investigated. The FE model was then verified by comparing the ultimate bearing capacity and bearing capacity governed by local buckling of the existing test results. Using the validated FE modeling approach, parametric analyses were conducted on the local buckling behavior of 960 MPa HSS box section and I-section columns under axial compression. Moreover, the FE analysis results and the existing test results summarized in this paper were compared with the design curves in Chinese, American and European codes. It is found that the FE model established in this paper can accurately simulate the local buckling behavior of 960 MPa HSS columns under axial compression. The initial geometric imperfection and the residual stress have little influence on the ultimate stress of 960 MPa HSS columns, but exhibit a great influence on the local buckling stress. Compared with the design methods in the Chinese, American and European codes, the new design formulae proposed in this paper were recommended for the design of the local buckling stress and post-buckling ultimate stress of 960 MPa HSS columns under axial compression.