钢框架焊接节点局部屈曲累积损伤分析

为解决试验和三维有限元方法在模拟结构地震作用下的局限性，在构件阶段寻找损伤退化的影响因素以及退化特征对改进杆系模型计算的准确性显得尤为重要. 采用通用有限元软件ABAQUS建立非线性有限元模型，结合国内外已有的钢框架焊接节点拟静力试验，验证了建立的有限元模型对模拟局部屈曲的准确性和适用性. 通过算例参数分析，对钢框架梁柱节点局部屈曲累积损伤现象进行深入探讨，得到节点局部屈曲累积损伤退化分布曲线形式并分析影响因素，进而得到节点强度退化的规律，为提出考虑损伤退化的杆系模型提供有力的工具. 参数分析结果表明：剪切域强弱以及板件宽厚比对于节点的破坏模式有较大影响. 通过局部加强，改变节点的破坏模式，可以有效提高结构的延性和耗能能力，防止结构由于焊缝开裂导致提前破坏，在大震作用下退化程度快进而严重影响结构的整体受力性能.

Analysis of local buckling cumulative damage of steel frame welded connections

To overcome the limitation to simulate thestructure under earthquake with tests and three-dimensional finite element method,it is important to search for damage and degradation factors and the degradation characteristics in component stage to improve the accuracy of member model.ABAQUS is used and the non-linear finite element model is proved correct and applicable by the existed steel frame connections quas-static tests at home and abroad.By a large number of parameters analysis,the local buckling cumulative damage phenomena of steel frame connections is further discussed and local buckling cumulative damage degradation distribution curve is obtained.Due to analysis of influence factors,the connections strength degradation is acquired which is a powerful tool for member model analysis considering of damage and degradation.The results show that the panel zone strength and thickness ratios of plates have significant impact on failure mode of connections.By local reinforcement to change the connections failure mode can effectively improve the ductility and energy dissipation,prevent weld cracking that will lead to early damage and fast degradation under large earthquake which would seriously affect the overall mechanical properties of the structure.