不锈钢焊接箱形截面短柱轴压局部稳定性能

Local buckling behavior of axially loaded stub columns with welded stainless steel box sections

设计并加工了7个奥氏体型S30408和6个双相型S22253不锈钢焊接箱形截面短柱试件,通过压缩材性试验得出了2种不锈钢板材的力学性能指标,同时量测了试件的几何初始缺陷和焊接残余应力分布形态.此外,在两端固接的约束条件下开展短柱轴压试验,得到了试件的局部稳定承载力和屈曲失效形态.试验结果表明,随着板件宽厚比的增大,其局部稳定承载力逐渐降低.采用ABAQUS建立考虑材料非线性和各向异性、几何初始缺陷和焊接残余应力的有限元模型,对短柱轴压局部稳定性能进行了数值模拟,计算结果与试验结果吻合良好,验证了有限元模型的准确性和可靠性.得到的短柱试验结果和建立的有限元模型可以为焊接不锈钢构件稳定性能的研究提供参考.

The stainless steel stub column specimens with box sections were designed and fabricated by welding, among which seven specimens were made of austenitic grade S30408 and six other ones were made of duplex grade S22253. The material properties of both kinds of stainless steel plates were obtained by compressive coupon tests, and the initial geometric imperfections and welding re- sidual stresses were accurately determined. In addition, the stub column tests were conducted under axial compression with fixed end boundary conditions to obtain the buckling capacities and failure modes. The experimental results show that the local buckling capacity gradually decreases along with the increase in plate width-to-thickness ratios. Meanwhile, the ABAQUS software package was used to develop finite element （FE） models that take into account nonlinear material properties, effects of anisotropy, initial geometric imperfections and welding residual stresses. Numerical simulations for the stub column tests were performed by the FE models, which indicate good agreement between the FE predictions and test results. The accuracy and reliability of the developed FE models were, there- fore, validated. The obtained test results and the corresponding FE models can be used for further re- search on the stability of welded structural stainless steel members.