基于扩展有限元法的钢桥面横隔板弧形切口疲劳裂纹扩展特性研究  

Research on Propagation Behaviors of Fatigue Cracks ofArc-Cutouts in Diaphragms Based on XFEM

作　　者：向泽 刘力 祝志文 XIANG Ze;LIU Li;ZHU Zhiwen(Key Laboratory of Green Construction and Intelligent Monitoring in Southwestern Hunan for Regular Higher Educational Institutions of Hunan Province,Shaoyang 422000,China;Hunan Provincial Engineering Research Center of Bamboo Fiber Construction Materials,Shaoyang University,Shaoyang 422000,China;China Railway Britech Co.,Ltd.,Wuhan 430034,China;Department of Civil and Intelligent Construction Engineering,Shantou University,Shantou 515063,China)

机构地区：[1]湘西南绿色建造与智能监测湖南省普通高等学校重点实验室,湖南邵阳422000 [2]邵阳学院竹纤维建造材料湖南省工程研究中心,湖南邵阳422000 [3]中铁桥研科技有限公司,湖北武汉430034 [4]汕头大学土木与智慧建设工程系,广东汕头515063

出　　处：《桥梁建设》2024年第3期46-53,共8页Bridge Construction

基　　金：国家自然科学基金项目(52278509);湖南省自然科学基金项目(2022JJ50030);湖南省教育厅科学研究项目(21B0684)~~。

摘　　要：为了解正变异性钢桥面板横隔板弧形切口疲劳开裂的规律,以某跨径350 m的独塔单跨钢箱梁自锚式悬索桥为背景,基于扩展有限元法建立纵肋-横隔板弧形切口多尺度裂纹扩展数值模型,求解弧形切口在轮载作用下的应力强度因子,分析轮载-热残余应力耦合作用下的疲劳裂纹扩展形态和特性。结果表明:当顺桥向车轮作用于弧形切口正上方时,应力强度因子急剧增大,基于该响应曲线可以识别疲劳荷载模型的轴组,但无法识别轴组内的单轴。弧形切口切向热残余拉应力峰值达到341.1 MPa,使得轮载作用下的压应力幅转换为拉应力幅,裂纹扩展方向与实桥疲劳裂纹的扩展形态基本吻合。由于弧形切口处于复杂的三维变形状态,以面内变形为主,因而弧形切口为Ⅰ型断裂主导的Ⅰ-Ⅱ-Ⅲ型复合裂纹扩展模式,裂纹扩展速率与应力强度因子幅均随着裂纹扩展呈现出先增大后减小的趋势。This study investigates the fatigue cracking performance of arc-cutouts in diaphragms of orthotropic steel deck.An existing steel box girder self-anchored suspension bridge,which features a single tower and a single-suspended main span of 350 m,was used as a case.Multi-scale models that simulate the crack propagation behaviors of arc-cutouts of U ribs and diaphragms were built up by the extended finite element method(XFEM).The stress intensity factors of the arc-cutouts under wheel loads were calculated,and the propagation mode and characteristics of fatigue cracks under the interaction of wheel loads and thermal residual stresses were analyzed.It was found that when the wheel loads acted directly above arc-cutouts,the stress intensity factors exhibited a drastic increase,based on this response curve,the axle groups of the fatigue loading models can be identified,but single axles in each axle group can not be extracted.The peak tangential residual tensile stress in the arc-cutouts reached 341.1 MPa,forcing the compressive stress range under the wheel loads to convert to tensile stress range,and the crack propagation direction are basically consistent with the actual crack propagation mode of the real bridge.Due to that the arc-cutouts are in complex three-dimensional shape deformation state,with in-plane deformation in dominance,the arc-cutouts display the mix ofⅠ,Ⅱ,andⅢtypes of cracks,with theⅠ-type fracture playing a dominant role.As the cracks propagate,the cracking propagation velocity and stress intensity factor range shows the sign of from increasing to decreasing.

关 键 词：正交异性钢桥面板 模隔板 弧形切口 疲劳 裂纹 应力强度因子 热残余应力 扩展有限元法 

分 类 号：U443.32[建筑科学—桥梁与隧道工程] U441.4[交通运输工程—道路与铁道工程]