摘要
建立顶板与U肋有限元模型,采用扩展有限元模拟顶板弯曲荷载与U肋变形次应力作用下的水平裂纹,计算裂纹在不同作用下的应力特征及应力强度因子,对比开裂前后顶板与U肋焊缝的应力分布变化。计算止裂孔位于裂纹或其延长线相切时,不同止裂孔位置下的顶板焊趾与U肋焊趾的应力变化,对比止裂孔外侧应力,确定合理的止裂孔位置。通过实桥测试,确定钻孔止裂对缓解水平裂纹应力集中的作用。结果表明：水平裂纹在承受顶板弯曲荷载作用时,表现为张开型与撕开型的复合裂纹,在受到U肋变形产生的次应力作用时,主要表现为张开型裂纹。钻孔止裂可以缓解水平裂纹的二次开裂,为了避免钻孔后顶板焊趾与U肋焊趾应力集中,减少裂纹扩展母材的削弱,建议止裂孔边缘恰好与裂纹尖端相切。
The finite element model of deck and U-rib was established. The horizontal cracks under bending load and secondary stress of U-rib deformation were simulated respectively by using EFEM. The stress characteristics and stress intensity factors of the horizontal crack under different stresses were calculated. The stress distributions before and after cracking were compared. The stop-hole was tangent to the crack or its extension cord. The stress variations of weld toe on deck and U-rib were calculated with different stop-hole positions. The effect of the stop-hole on remitting the stress concentration of horizontal crack was studied by actual bridge test. The analysis results indicated that the crack was mixed mode crack with type Ⅰ and type Ⅲ under bending load. The crack was mainly type Ⅰunder the secondary stress of U-rib deformation. Stop-hole could relieve re-cracking of the horizontal crack. In order to avoid the stress concentration of the weld toe on the deck and U-rib and the section weakening caused by crack propagation,the paper suggested that the edge of stop-hole should be tangent to the crack tip.
作者
姚悦
傅中秋
徐捷
吉伯海
YAO Yue;FU Zhongqiu;XU Jie;JI Bohai(College of Civil and Transportation Engineering,Hohai University,Nanjing 210098,China)
出处
《工业建筑》
CSCD
北大核心
2018年第10期40-45,共6页
Industrial Construction
基金
国家自然科学基金项目(51678216,51678215)
关键词
顶板与U肋焊缝
水平裂纹
止裂孔
孔位
U-rib to deck weld joint
horizontal crack
stop-hole
stop-hole positon
