动荷载作用下钢结构涂装的累积损伤机理与量化模型  

Cumulative Damage and Prediction Model of Steel Structure Coating Under Dynamic Load

作　　者：蔺鹏臻[1] 戚彦福 李籽祺 李岩 潘亚磊 LIN Peng-zhen;QI Yan-fu;LI Zi-qi;LI Yan;PAN Ya-lei(Key Laboratory of Road&Bridge and Underground Engineering of Gansu Province,Lanzhou Jiaotong University,Lanzhou 730070,Gansu,China)

机构地区：[1]兰州交通大学甘肃省道路桥梁与地下工程重点实验室,甘肃兰州730000

出　　处：《中国公路学报》2022年第6期113-121,共9页China Journal of Highway and Transport

基　　金：国家自然科学基金重大项目(11790281);甘肃省交通运输厅科研项目(2020-08);中央引导地方科技发展资金专项(2022-15)。

摘　　要：为研究动荷载作用下公路钢桥涂装层与基体间的协同变形和破坏机制,开发了钢结构涂装层试件的动荷载试验系统,研究了疲劳荷载作用下涂层的破坏模式、附着力、弹性厚度、应变等随循环加载次数的发展规律。结合涂层破坏模式和发展规律,构建了涂层疲劳累积损伤度的计算模型,提出了基于损伤度的涂层破坏分级方法,并结合试验结果进行了验证。结果表明:疲劳荷载将引起涂层的附着力下降、弹性厚度降低和应变松弛,进而导致涂层出现附着破坏、内聚破坏及其组合。涂层附着损伤度是涂层损伤的主要因素,且随加载次数持续增大,当加载次数较大时内聚损伤贡献突出。试验涂装体系在22万次应力循环后附着损伤度最大为0.34,内聚损伤度最大为0.27,总损伤度达0.61,属于严重损伤。提出的损伤度模型及破坏分级方法与试验规律吻合良好,可应用于公路钢桥涂装层受动荷载作用下的寿命预测。In order to study the cooperative deformation and failure mechanism between coating layer and substrate of highway steel bridge under dynamic load, a dynamic load test system for steel structure coating specimens was developed, and the development laws of coating failure mode, adhesion, elastic thickness and strain relaxation with cyclic loading times under fatigue stress were studied. Combined with the coating failure mode and development law, the calculation model of coating fatigue cumulative damage degree was constructed, and the coating failure classification method based on damage degree was proposed, which was verified by the test results. The results show that fatigue load would cause the decrease of adhesion, elastic thickness and strain relaxation of the coating, and then lead to adhesion failure, cohesion failure and their combination. The degree of coating adhesion damage was the main factor of coating damage, and increases continuously with the number of loading times. When the number of loading times was large, the contribution of cohesion damage was prominent. After 220000 stress cycles, the maximum adhesion damage degree of the test coating system was 0.34, the maximum cohesion damage degree was 0.27, and the total damage degree was 0.61, which belongs to serious damage. The damage degree model and damage classification method proposed in this paper were in good agreement with the test law, and could be applied to the life prediction of coating layer of highway steel bridge under dynamic load.

关 键 词：桥梁工程 钢结构涂层 动荷载 累积损伤 预测模型 劣化等级 

分 类 号：U443.33[建筑科学—桥梁与隧道工程]