3种钢桥细节基于断裂力学方法的裂纹扩展研究

选取栓焊钢桥3种典型细节(单面盖板搭接节点、不承载角焊缝节点、摩擦型高强螺栓连接节点),用FRANC2D/L软件对这3种细节的裂纹扩展进行模拟分析,给出3种细节在单边裂纹和双边裂纹模式下的几何形状因子计算公式,并得到这3种细节裂纹扩展过程中应力强度因子与裂纹长度的关系,其中,对于单面盖板搭接节点:双边裂纹的KI值要比单边裂纹的KI值略大一些;对于不承载角焊缝节点:单边裂纹的KI值要比双边裂纹的KI值大一些;对于摩擦型高强螺栓连接节点:单边裂纹和双边裂纹的KI值几本相同。研究的结果可直接用于这3种钢桥细节的疲劳寿命预测。

Research on Crack Extending of Three Steel Bridge Details Based on Fracture Mechanics Method

The simulations of crack extending of three typical details of bolted and welded steel bridge including one-side covering plate lap joints,non-load-bearing fillet weld joints and high-strength bolted friction-type joints were proceeded by FRANC2D/L software.The calculation formulas of geometry form factors in the model of single side crack and both sides crack of these details were presented,and the relations between stress intensity factor and crack length in the process of crack extending were observed.The results show that(1) for one-side covering plate lap joints,the stress intensity factor(KI) of both sides crack is larger than that of single side crack;(2) for non-load-bearing fillet weld joints,the stress intensity factor(KI) of single side crack is larger than that of both sides crack;(3) for high-strength bolted friction-type joints,the stress intensity factor(KI) of single side crack is similar to that of both sides crack.These results can be used to evaluate fatigue lives of these steel bridge details.