钢桥复杂构造疲劳裂纹跨尺度扩展与寿命预测  

Multiscale fatigue crack growth and life prediction for complex details of steel bridges

作　　者：崔闯[1] 郑秋松 袁晓鹏 张宁 张清华[1] Cui Chuang;Zheng Qiusong;Yuan Xiaopeng;Zhang Ning;Zhang Qinghua(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Shanghai Municipal Engineering Design Institute(Group)Co.,Ltd.,Shanghai 200092,China)

机构地区：[1]西南交通大学土木工程学院,成都610031 [2]上海市政工程设计研究总院(集团)有限公司,上海200092

出　　处：《东南大学学报（自然科学版）》2024年第3期578-585,共8页Journal of Southeast University：Natural Science Edition

基　　金：国家重点研发计划资助项目(2022YFB3706405);国家自然科学基金资助项目(52108176,52278318)。

摘　　要：针对传统宏观唯像学方法无法描述钢桥疲劳损伤由微观到宏观的多尺度演化过程的问题,建立了可描述钢桥复杂构造疲劳裂纹跨尺度扩展与寿命预测方法.首先,结合微观晶体塑性本构模型,建立了以能量耗散理论为基础的微观短裂纹成核与扩展模型.同时,结合线弹性断裂力学,建立了宏观长裂纹扩展模型.在此基础上,以钢桥典型的纵肋与顶板焊接构造细节为研究对象,结合既有疲劳试验,模拟并验证了微观短裂纹的成核、扩展,以及宏观长裂纹扩展全过程.数值模拟结果与试验结果基本一致,表明所提出的疲劳裂纹跨尺度扩展与寿命预测方法对于钢桥复杂构造细节疲劳损伤演化与评估具有较好的适用性.Since the traditional macroscopic phenomenology cannot describe the multiscale evolution process of fatigue damage in steel bridges from micro to macro,a method for describing the multiscale fatigue crack growth and life prediction in complex structures of steel bridges is proposed.Firstly,combining with the microscopic crystal plasticity constitutive model,a microscopic short crack nucleation and growth model is established based on the energy dissipation theory.Meanwhile,a model for macro long crack growth is established by combining the linear elastic fracture mechanics.On this basis,taking the welding structure details of typical longitudinal rib and roof plate of steel bridge as the research object,the whole process of nucleation and propagation of micro short crack and macro long crack is simulated and verified using the existing fatigue test.The numerical simulation results are basically in agreement with those of the test.It is shown that the proposed method for predicting multiscale fatigue crack spanning and life has good applicability for fatigue damage evolution and assessment of details of steel bridges with complex structures.

关 键 词：钢桥 疲劳损伤演化 位错偶极子模型 短裂纹成核扩展 长裂纹扩展 

分 类 号：U441.4[建筑科学—桥梁与隧道工程]