楔形翼缘连接板腹板连接节点断裂性能

Studies on fracture behavior of beam-to-column web connections with tapered beam flange plates in steel moment frames

为定量确定采用楔形翼缘连接板的钢框架结构梁柱腹板连接节点焊缝应力强度因子与初始缺陷深度之间的函数关系,采用断裂力学与有限元分析相结合的方法.判断焊缝开裂的依据是一型应力强度因子,应力强度因子通过J积分的方法求得.通过有限元计算研究初始裂缝深度、梁截面尺寸、柱截面尺寸、梁柱长度和翼缘连接板伸出柱边缘的长度对腹板连接节点焊缝应力强度因子的影响.采用正交设计法进行研究方案设计,根据参数分析结果归纳出应力强度因子计算公式.结果表明,梁下翼缘焊缝比上翼缘更容易开裂,采用楔形翼缘连接板可以明显改善焊缝边缘的断裂性能,应力强度因子与梁截面参数是增函数关系,与柱截面参数是减函数关系.

To quantify the variation of stress intensity factor to weld root flaw sizes in beam - to - column web connections, a methos that combines fracture mechanics and finite element analysis is presented. Fracture toughness demands were evaluated in terms of the Mode I stress intensity factor. The stress intensity factor was calculated through J - integral approach. The connection geometry was separately investigated in terms of the beam and column properties. The influences of the length of beam, column and beam flange plate on the stress intensity factor were analyzed. The fracture toughness demands were studied for the flaw on the top of the beam flange and the bottom surface, respectively. Finally, formulas for stress intensity factor were derived by orthogonal design. Results show that the deformation of panel zone has significant effects on stress intensity factor. The likelihood of top flange fractures is smaller than that of bottom flange fracture. Stress intensity factor increases with the increase of beam parameters and is reduced with the increase of column parameters.