不同焊接节点构造形式钢框架整体抗震性能分析

ANALYSIS ON SEISMIC BEHAVIOR OF OVERALL STEEL FRAME WITH DIFFERENT WELDED CONNECTION CONSTRUCTIONS

为系统全面地对比不同构造形式对于焊接节点钢框架抗震性能的影响,该文采用通用有限元软件ABAQUS,建立多尺度钢框架非线性有限元模型,应用国内外典型试验结果,验证了精细模型和多尺度有限元模型的准确性和等效性。通过建立9种不同节点构造形式的钢框架多尺度模型,进行罕遇地震下的弹塑性时程分析,与标准型节点框架在结构变形、基底剪力、塑性耗能、断裂倾向指数等方面进行对比分析,深入探讨不同节点构造形式对钢框架抗震性能的影响,为工程应用提供参考依据。分析结果表明:只要设计合理,局部构造差异对于结构变形的影响不大,不会引起刚度的突变进而对结构造成不利的影响;对于局部加强节点框架,没有造成基底剪力的增加(少数增加最大为6%),降低了结构的地震响应,这对于结构抵抗地震荷载起到有利作用;改变节点构造可以显著地改善节点焊接接头处的断裂倾向,减缓节点焊接处的应力集中现象,使得破坏发生在母材而不是焊缝处,进而发生延性破坏避免脆性破坏。

In order to compare the influence on the seismic behavior of different connection constructions of a steel frame systematically, an efficient and accuracy finite element model of ABAQUS is used. The accuracy and equivalence of the non-linear fine model and multi-scale model are proved by published steel-frame-connection quasi-static tests at home and abroad. Nine multi-scale models of different connection construction steel frames are established and elastic-plastic time-history analyses are used. The structural deformation, base shear, plastic energy dissipation and fracture tendency index are compared and discussed in depth.The results show that： as long as the design is reasonable, the connection construction differences have little effect on structural deformation and do not cause the stiffness mutation and adverse effects on struetures; reinforced connections do not cause the increase of the base shear （little increase up to 6%）, which reduce the seismic response and have beneficial effect on structures to resist seismic loading; the change of constructions can significantly improve the fracture tendency at the welded toe to relieve the stress concentration at weld so that make the damage in the base metal but not weld itself in order to avoid brittle ductile occurrence.