摘要
为探讨厚壁箱形钢桥墩的超低周疲劳裂纹萌生寿命及裂纹扩展规律,利用ABAQUS有限元分析软件对多组厚壁箱形钢桥墩在恒定竖向荷载和水平往复荷载作用下的超低周疲劳裂纹萌生、扩展与破坏过程进行数值模拟分析。对钢桥墩试件的1/2进行建模,采用壳单元和梁单元相结合的方法提高计算效率。采用基于Rice-Tracey模型的裂纹萌生准则和钢材混合强化模型对厚壁箱形钢桥墩的超低周疲劳裂纹萌生寿命进行预测,并使用一种基于极限断裂位移的裂纹扩展准则对超低周疲劳裂纹的扩展过程进行模拟。通过与既有试验结果的对比,验证所采用的裂纹萌生准则预测裂纹萌生寿命的准确性,以及所采用的裂纹扩展准则预测厚壁箱形钢桥墩裂纹扩展过程的准确性。对影响厚壁箱形钢桥墩疲劳裂纹萌生寿命、裂纹扩展规律的因素(即翼缘正则化宽厚比、正则化长细比、加载方式)进行参数化分析,研究厚壁箱形钢桥墩在不同结构参数条件下的破坏模式。将裂纹萌生寿命与超低周疲劳破坏寿命的差值定义为钢桥墩超低周疲劳剩余寿命,分析不同结构参数条件对钢桥墩超低周疲劳剩余寿命的影响。由于裂纹萌生寿命的模拟结果与试验结果较吻合,因此基于Rice-Tracey模型的裂纹萌生准则和钢材混合强化模型能准确预测厚壁箱形钢桥墩的裂纹萌生寿命。裂纹扩展长度的模拟结果与试验结果也吻合良好,因此基于极限断裂位移的裂纹扩展准则能准确预测厚壁箱形钢桥墩超低周疲劳裂纹的扩展过程。在验证有限元分析方法准确性的基础上,通过比较超低周疲劳破坏点与局部屈曲破坏点发生的时刻以及基于裂纹扩展长度的参数化分析结果,提出了不同结构参数条件下的三种破坏模式,分别为超低周疲劳破坏模式、局部屈曲破坏模式与混合破坏模式。结果表明:超低周疲劳破坏发生�
In order to investigate the Extremely Low-Cycle Fatigue(ELCF) crack initiation life and crack propagation process of thick-walled steel box-section bridge piers, a series of thick-walled steel box-section piers subjected to a constant vertical load and cyclic lateral loading are numerically simulated by using ABAQUS software package. To improve the computing efficiency, 1/2 of the pier is modelled and the method to combine the shell element and beam element is employed to simulate the lower part and upper part of the piers, respectively. The crack initiation criterion based on Rice-Tracey model and the combined hardening model of steel is utilized to predict ELCF crack initiation life. A method based on ultimate fracture displacement is used to simulate ELCF crack propagation process. The accuracy of the crack initiation criterion and the crack propagation criterion to predict the ELCF crack initiation life and crack propagation process is verified by comparing the analytical results with test results. The factors affecting the ELCF crack initiation life and crack propagation process of the piers(i.e., normalized flange’s width-thickness ratio, normalized slenderness ratio, and loading pattern) are parametrically studied, and the failure modes of the piers under different structural parameters are investigated. The difference between the crack initiation life and the ELCF failure life is defined as the ELCF residual life. The effect of structural parameters on the ELCF residual life of the piers is discussed. The agreement of the crack initiation life between the simulation result and test result indicates that the crack initiation criterion based on the Rice-Tracey model and the combined hardening model of steel can accurately predict the crack initiation life of the piers. The agreement of the crack growth length between the simulation result and test result demonstrates that the crack propagation criterion based on the ultimate fracture displacement can accurately predict the ELCF crack propagation process o
作者
朱婷
高圣彬
Ting Zhu;Shengbin Gao(Department of Civil Engineering,School of Naval Architecture,Ocean and Civil Engineering,Shanghai Jiaotong University,Shanghai 200240,China;College of Civil Engineering,Shanghai Normal University,Shanghai 201418,China)
出处
《钢结构（中英文）》
2021年第10期16-24,共9页
Steel Construction（Chinese & English）
基金
国家自然科学基金项目(51778361)。
