摘要
主缆作为悬索桥不可更换的关键承重构件,其钢丝的疲劳寿命将直接影响桥梁的安全性和耐久性。由于主缆通常暴露于侵蚀环境中,往往会产生不同形式的腐蚀效应,其中点蚀是一种破坏力强且十分典型的腐蚀损伤,通常会成为疲劳裂纹萌生的初始点,从而显著降低构件的疲劳寿命。为研究点蚀效应对超高强钢丝疲劳性能的影响,采用能反映腐蚀电化学机理的元胞自动机模型模拟点蚀复杂形成过程,并基于盐雾试验标定演化参数,获得超高强钢丝的表面点蚀坑模型;在ABAQUS中开发基于连续损伤力学的UMAT子程序,实现腐蚀钢丝的疲劳损伤演化与寿命预测,揭示腐蚀程度、蚀坑形状参数对超高强钢丝的损伤演化规律和疲劳寿命的影响。结果表明:采用元胞自动机方法能够准确模拟钢丝点蚀过程,生成的模型可以很好地展现真实的蚀坑形态和特征;在蚀坑处最早出现损伤,前中期损伤速率较慢,后期发展迅速;随着疲劳荷载的加载,蚀坑处会发生应力重分布现象,蚀坑底部的应力逐渐降低,周边应力反而增加;在元胞自动机中以质量损失率表征钢丝腐蚀程度,当钢丝的质量损失率从0.1%增加到0.25%时,其疲劳寿命减少约36.8%;点蚀坑的深宽比越大,形状越尖锐,钢丝越容易发生疲劳破坏。研究结果可为腐蚀环境下超高强钢丝的疲劳寿命评估和提高桥梁的耐久性提供参考。
The main cable is a key load-bearing component that cannot be replaced in suspension bridges.The fatigue life of its steel wire directly affects the safety and durability of the bridge.Since the main cable is usually exposed to corrosive environments,it tends to produce different forms of corrosion effects.Among them,pitting corrosion is a highly destructive and typical corrosion damage,which usually becomes the initial point of fatigue crack initiation,significantly reducing the fatigue life of the component.To study the effect of pitting corrosion on the fatigue performance of ultra-high strength steel wire,this article used a cellular automata model that reflects the electrochemical mechanism of corrosion to simulate the complex formation process of pitting corrosion,and calibrated the evolution parameters based on salt spray test to obtain a surface pitting pit model of ultra-high strength steel wire.A UMAT subroutine based on continuous damage mechanics was developed in ABAQUS to achieve fatigue damage evolution and life prediction of corroded steel wires.The effects of corrosion degree and pit shape parameters on the damage evolution and fatigue life of ultra-high strength steel wires were revealed.The results show that the use of cellular automata method can accurately simulate the process of steel wire pitting,and the generated model can well demonstrate the true morphology and characteristics of pitting.The damage first appeared at the erosion pit,with a slower rate in the early and middle stages and a rapid development in the later stages.With the application of fatigue loading,stress redistribution occurs at the corrosion pit,and the stress at the bottom of the corrosion pit gradually decreases,while the surrounding stress increases instead.In cellular automata,the degree of steel wire corrosion is characterized by the mass loss rate.When the mass loss rate of the steel wire increases from 0.1%to 0.25%,its fatigue life decreases by about 36.8%.The larger the depth to width ratio of pitting pits,the sha
作者
王晓明
张浩楠
邓华
张煜博
彭寒笑
WANG Xiaoming;ZHANG Haonan;DENG Hua;ZHANG Yubo;PENG Hanxiao(School of Highway,Chang’an University,Xi’an 710065,China;Key Laboratory of Old Bridge Detection and Reinforcement Technology in the Transportation Industry(Xi’an),Xi’an 710064,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2024年第6期2523-2534,共12页
Journal of Railway Science and Engineering
基金
国家自然科学基金资助项目(52178104)
长安大学中央高校基本科研业务费专项资金资助项目(073182656536)。
关键词
超高强钢丝
元胞自动机
腐蚀疲劳
损伤演化
疲劳寿命
ultra-high strength steel wire
cellular automata
corrosion fatigue
damage evolution
fatigue life
