疲劳裂纹的跨尺度分析  

Trans-scale analysis for fatigue crack

作　　者：李明[1] 刘扬[1] 唐雪松[1] 

机构地区：[1]长沙理工大学土木与建筑学院,湖南长沙410114

出　　处：《浙江大学学报（工学版）》2017年第3期524-531,共8页Journal of Zhejiang University：Engineering Science

基　　金：国家"973"重点基础研究发展规划资助项目(2015CB057701;2015CB057704;2015CB057705);国家自然科学基金资助项目(51378081);长沙理工大学土木工程湖南省优势特色重点学科创新性研究资助项目(16ZDXK04)

摘　　要：为了准确模拟正交异性钢桥面板疲劳裂纹扩展行为,提出基于约束应力区的三维表面半椭圆跨尺度裂纹模型.采用有限元法求解应力强度因子,将跨尺度应力强度因子作为疲劳裂纹从微观到宏观扩展的控制参量,使用统一模型描述正交异性钢桥面板疲劳破坏全过程.对正交异性钢桥面板的疲劳失效行为进行数值模拟,并与试验应力-寿命曲线进行对比分析.结果表明:疲劳裂纹扩展跨尺度模型能正确反映正交异性钢桥面板纵肋与桥面板焊接部位的疲劳破坏过程,并可模拟疲劳裂纹扩展从微观到宏观的跨尺度行为.由于微观效应对疲劳寿命有显著影响,当考虑到材料的微观效应时,该模型可解释疲劳寿命试验数据的离散现象.A trans-scale model of 3Dsemi-ellipse surface crack based on the restraining stress zone was developed for accurately simulate the fatigue crack propagation behavior of orthotropic steel bridge deck.The finite element method was applied to calculate the stress intensity factor.The trans-scale stress intensity factor was used as controlling parameter for the fatigue crack growth from micro-scale to macroscale.Therefore,the whole fatigue failure process could be described by a unified model.Numerical simulation was performed for the fatigue failure behavior of an orthotropic steel bridge deck.Comparison and analysis were made between the theoretical results and experimental S-N curves.Results indicate that the trans-scale fatigue crack growth model can correctly describe the fatigue failure process of the welded joint between bridge deck and U-rib of orthotropic steel bridge decks.As is known that the microscopic effects have great influence on the fatigue life;when the microscopic effects are taken into account,the scatter of the fatigue test data can be explained by the proposed multi-scale model.

关 键 词：正交异性钢桥面板 疲劳裂纹扩展 跨尺度模型 应力-寿命曲线 有限元法 应力强度因子 

分 类 号：U441[建筑科学—桥梁与隧道工程]