腹板连接节点焊缝应力强度因子的参数分析

为定量的确定荷载作用下钢框架结构延长翼缘连接板梁柱腹板连接节点焊缝应力强度因子的大小,采用断裂力学与有限元积分相结合的方法，研究腹板连接节点的断裂性能.判断延长翼缘连接板腹板连接节点焊缝开裂的依据是Ⅰ型应力强度因子,应力强度因子可以通过有限元计算J积分的方法求得.通过有限元计算分析了初始裂纹深度、梁截面尺寸、柱截面尺寸和梁柱长度对延长翼缘连接板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,根据有限元分析结果归纳出应力强度因子计算公式.研究结果表明：延长翼缘连接板腹板连接节点梁下翼缘焊缝比上翼缘更容易开裂,应力强度因子随梁截面参数的增大而增大,随柱截面参数的增大而减小.

Parametric analyse of stress intensity factors of beam-to-column web connections in steel moment frames

A method that combined fracture mechanics and finite element was presented to quantify the variation of stress intensity factor to weld root flaw sizes in beam-to-column web connections with extended beam flange plates. Fracture toughness demands of web connections with extended beam flange plates were evaluated in terms of the mode I stress intensity factor. The stress intensity factor was calculated through a J-integral approach. The connection geometry was separately investigated in terms of the beam and column properties by finite element method. The influences of the length of beam and the length of column on the stress intensity factor were analyzed. The fracture toughness demands for the flaw on the top of the beam flange and for the bottom surface were studied, respectively. Finally, formulas for stress intensity factor were derived by orthogonal design and the results of finite element analysis. Results show that 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 reduces with the increase of column parameters.