基于断裂力学的腐蚀钢丝疲劳S-N曲线研究  

Fatigue S-N curve of corroded steel wires based on fracture mechanics

作　　者：叶华文[1] 叶杨帆 邓雪峰 杨军川 徐勋[1] YE Huawen;YE Yangfan;DENG Xuefeng;YANG Junchuan;XU Xun(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Chengdu Municipal Engineering Design and Research Institute Company Ltd.,Chengdu 610023,China;Sichuan Zitong Expressway Company Ltd.,Chengdu 641300,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]成都市市政工程设计研究院有限公司,四川成都610023 [3]四川资潼高速公路有限公司,四川成都641300

出　　处：《铁道科学与工程学报》2024年第5期1990-2000,共11页Journal of Railway Science and Engineering

基　　金：国家重点研发计划资助项目(2023YFB2604400,2023YFB2604403);国家自然基金面上项目(52278219);中国中铁股份有限公司科技研究开发计划(2023-专项-02)。

摘　　要：高强冷拔钢丝因其优异的力学性能被广泛应用于缆索承重结构,服役过程中钢丝腐蚀与断裂威胁着结构安全。钢丝腐蚀后表面的蚀坑因应力集中效应易产生疲劳裂纹,因此腐蚀钢丝剩余疲劳寿命主要取决于裂纹的扩展阶段,且裂纹扩展受到腐蚀程度(初始损伤)的显著影响。精确表征腐蚀程度并准确评估服役期钢丝腐蚀后的剩余寿命,仍是亟待解决的维修难题。首先采用蚀坑最大深度表征钢丝腐蚀程度,以应力强度因子幅作为裂纹扩展驱动力指标,基于断裂力学的Paris公式建立受拉钢丝裂纹扩展理论模型,进而推导腐蚀钢丝的疲劳S-N曲线。大量既有的腐蚀钢丝疲劳试验结果与理论预测值的比较验证了所提理论模型及疲劳S-N曲线的合理性和有效性。含多个蚀坑的钢丝裂纹扩展有限元模拟表明,等效单裂纹适用于多腐蚀坑钢丝疲劳寿命的简化分析。参数分析表明,蚀坑深度和腐蚀环境是腐蚀钢丝疲劳强度的关键影响因素,而应力比和疲劳加载频率影响较小,所提出的S-N曲线在钢丝常规服役条件下适用于评估其剩余寿命,可得到合理的预测结果。基于断裂力学所提的理论方法和疲劳S-N曲线可为腐蚀钢丝的疲劳强度和寿命评估提供参考。High-strength cold-drawn steel wire is widely used in cable load-bearing structures due to its excellent performance,but the corrosion and fracture of steel wire pose a threat to the structure safety in service.Pitting corrosion on the wire surface can lead to fatigue cracks due to stress concentration effects.Therefore,the residual life of corroded steel wire depends mainly on the crack propagation stage,and crack growth is significantly influenced by the corrosion degree(initial damage).Accurate characterization of the corrosion degree and precise assessment of the remaining life of corroded steel wire remain a challenge in maintenance.In this study,the maximum depth of corrosion pit was used to represent the corrosion degree,and the stress intensity factor range was used as the driving force indicator for crack propagation of the tensile steel wire.A theoretical model for crack propagation was established using the Paris equation based on fracture mechanics,from which the fatigue S-N curve of tensile corroded steel wire was derived.Extensive comparisons between the results of numerous corrosion wire fatigue tests and the theoretical predictions can validate the rationality and effectiveness of the proposed theoretical model and the S-N curve.Finite element simulations of crack propagation in steel wire with multiple corrosion pits demonstrate that an equivalent single crack can be used for simplified analysis of the fatigue life of steel wire with corrosion pits.Finally,parameter analysis indicated that pit depth and corrosion environment were key influencing factors on the fatigue strength of corroded steel wire,while stress ratio and fatigue loading frequency had minor effects.The proposed S-N curve can remain applicable for evaluating the remaining life of corroded steel wire under normal service conditions and yields reasonable predictive results.The theoretical approach based on fracture mechanics and the fatigue S-N curve presented here can serve as a reference for assessing the fatigue strength and resi

关 键 词：冷拔钢丝 腐蚀 剩余寿命 S-N曲线 蚀坑深度 

分 类 号：U447[建筑科学—桥梁与隧道工程]