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为研究焊接加固热作用及不同初始负载对工字形压弯钢柱承载性能的影响,基于考虑热影响的热结构耦合分析方法进行了热源模型热输入改进,并考虑初始几何缺陷、初始残余应力及摩擦等,完成了不同负载下焊接加固的3个工字形压弯钢柱的模拟分析。研究了焊接位移时程、腹板应力应变重分布及荷载位移关系,通过有限元分析与相应试验结果对比验证,进而获得了试验无法获得的焊接温度场、翼缘与加固板间的焊接应力应变重分布以及翼缘边缘屈服承载力等结果,并将承载力结果与规范计算结果对比,考察了现有设计方法。结果表明,焊接顺序决定焊接变形的发展过程,焊接热输入和初始负载共同决定持载焊接的位移变化范围和焊接残余变形的大小;初始负载越大,应力应变重分布往偏心受力方向发展更多,承载力越低,而初始残余应力不影响极限承载力;采用考虑热影响的有限元方法具有一定可行性和总体安全性,规范设计方法仍有可提升空间。
In order to study the influence of welding reinforcement heat load and different initial load on the bearing capacity of I-shaped bent steel columns, heat input improvement based on heat structure coupled analysis method considering heat effect is taken into account. The initial geometric defects, initial residual stress and Friction and so on, completed the simulation analysis of 3 I-shaped bent steel columns strengthened by welding under different loads. The relationship between welding displacement time history, stress and strain redistribution and load displacement of the web is studied. The finite element analysis and the corresponding test results are compared to verify the welding temperature field, the welding stress and strain between the flange and the reinforcing plate Redistribution and yield edge of the flange edge yield results, and the results of the bearing capacity compared with the normative calculations, investigated the existing design methods. The results show that the welding sequence determines the development of welding deformation. The welding heat input and the initial load jointly determine the range of displacement and the residual welding deformation. The larger the initial load, the greater the initial stress is, the more the stress and strain are redistributed towards the direction of eccentric stress And the lower the bearing capacity, while the initial residual stress does not affect the ultimate bearing capacity. The finite element method considering the thermal effect has some feasibility and overall safety, and the standard design method still can improve the space.