方钢管混凝土柱-型钢梁节点断裂分析及延性节点研究

Fracture analysis and ductile joints of concrete filled square steel tube column-steel beam connections

运用结构钢椭球面屈服模型和椭球面断裂模型,对梁柱节点试验进行了数值模拟分析,得出了等效考虑焊接残余应力和焊接缺陷的对接焊缝断裂因子CI的修正系数k。对方钢管混凝土柱-型钢梁节点进行了基于椭球面强度模型的数值模拟和断裂分析,结果显示:柱对梁的强约束使对接焊缝处应力集中严重,该处的等效应力和平均应力幅值均较高,当对接焊缝应力场函数达到建议的椭球面断裂准则临界值时,该处发生断裂。以结构钢椭球面断裂模型为评判依据,提出了降低对接焊缝等效应力和平均应力幅值(即提高节点延性)的构造建议。

Using an elliptical yield model together with an elliptical fracture model,the correctional coefficient of fracture index was obtained to equivalently calculate the effects of residual stress and disfigurement through numerical simulation and fracture analysis of beam-column connection tests.The concrete filled square steel tube column-steel beam connections were numerical simulated and analyzed based on the elliptical yield model and the elliptical fracture model.Numerical results show that the strong constraint of column on the beam leads to high stress concentration in beam flange butt weld,where the equivalent stress and the average stress amplitude are high.The butt weld fractured when the stress function reached the ellipsoidal fracture critical value.Using the ellipsoidal fracture criterion for evaluation,the details of connection were proposed to reduce equivalent stress and average stress amplitude in butt weld.