高超龄铆接钢桥腐蚀后数字孪生疲劳评估模型

DIGITAL TWIN FATIGUE ASSESSMENT MODEL FOR CORRODED RIVETED STEEL BRIDGES WITH AGED OR OVER DESIGN SERVICE LIFE

  • 摘要: 腐蚀和疲劳是控制高超龄铆接钢桥服役安全和耐久使用的关键因素,腐蚀与疲劳的耦合作用会导致结构使用安全性显著下降,服役寿命缩减加剧。为了评估腐蚀后在役高超龄铆接钢桥的抗疲劳性能,基于马尔可夫过程和概率演化理论,建立了可体现桥梁钢材腐蚀规律的多参数点蚀概率分布与随机演化模型,采用Python语言编写了腐蚀自动建模程序;在经典Paris疲劳裂纹扩展公式中引入腐蚀损伤系数,提出了修正的Paris疲劳裂纹扩展公式。应用支持向量回归(SVR)的机器学习算法量化了腐蚀特征参数与腐蚀疲劳损伤系数的相关关系;验证分析结果表明该模型预测误差小于5%,拟合优度为0.95。进而使用修正的Paris公式,对腐蚀后铆接构件疲劳寿命进行了计算分析,计算结果与物理试验值平均误差小于10%。通过热铆接过程精细化模拟,实现了铆合力及铆接残余应力场向数字孪生模型的空间传递。将足尺铆接接头疲劳试验的物理力学信息映射于数字试验中,实现数据原生与孪生模型验证。对一座带腐蚀的铆接钢板梁桥进行数字孪生疲劳模拟与评估,建立全桥数字疲劳孪生模型,通过原位监测的原生数据进行校验。将腐蚀数据引入全桥数字疲劳孪生模型,进行腐蚀后疲劳裂纹扩展与演化模拟,分析腐蚀参数的影响规律,实现数据相生;对比分析不同腐蚀程度下模拟结果与修正Paris公式计算结果,两者差异亦在10%以内。本文提出的高超龄铆接钢桥腐蚀后数字孪生疲劳评估模型,量化了腐蚀特征参数和腐蚀后疲劳损伤的相关关系,且具有一定评估精度,可为实际工程服役寿命与使用安全评估提供参考,为创建高超龄铆接钢桥腐蚀、疲劳损伤元宇宙奠定基础。

     

    Abstract: Corrosion and fatigue are key factors controlling the service safety and durability of aged and over design service life riveted steel bridges. The coupling effect of corrosion and fatigue will significantly reduce the safety of the structure and aggravate the reduction of service life. In order to evaluate the fatigue performance of aged and over design service life riveted steel bridge after corrosion, a multi-parameter pitting probability distribution and random evolution model that can reflect the corrosion law of bridge steel was established based on Markov process and probability evolution theory, and the corrosion automatic modeling program was written in Python. The corrosion damage coefficient was introduced into the classic Paris fatigue crack growth formula, and a modified Paris fatigue crack growth formula was proposed. The machine learning algorithm of support vector regression (SVR) was used to quantify the correlation between the corrosion characteristic parameters and the corrosion fatigue damage coefficient. The verification analysis results showed that the prediction error of the model was less than 5%, and the goodness of fit was 0.93. Then, the fatigue life of the riveted components after corrosion was calculated and analyzed using the modified Paris formula, and the average error between the calculated results and the physical test values was less than 10%. Through the refined simulation of the hot riveting process, the spatial transfer of the riveting force and the riveting residual stress field to the digital twin model was realized. The physical and mechanical information of the full-scale riveted joint fatigue test was mapped into the digital test to realize the data native and twin model verification. A digital twin fatigue simulation and evaluation was conducted on a corroded riveted steel plate girder bridge, and a digital fatigue twin model of the entire bridge was established, which was verified by the original data of on-site monitoring. The corrosion data was introduced into the digital fatigue twin model of the entire bridge, and the fatigue crack propagation and evolution after corrosion were simulated. The influence of corrosion parameters was analyzed to achieve data generation; the simulation results under different corrosion degrees were compared with the calculation results of the modified Paris formula, and the difference between the two was also within 10%. The digital twin fatigue evaluation model for corroded riveted steel bridges proposed in this paper quantifies the correlation between corrosion characteristic parameters and fatigue damage after corrosion, and has a certain evaluation accuracy. It can provide a reference for the service life and safety evaluation of actual engineering, and provide technical support for the construction of metaverse of bridge fatigue damage.

     

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