自黏结预应力CFRP修复含缺陷钢板的疲劳性能  

Fatigue Performance of Self-bonded Prestressed CFRP Repaired Steel Plates Containing Defects

作　　者：陈卓异[1] 刘雁 王升旗 严子卓 彭晖[1] CHEN Zhuo-yi;LIU Yan;WANG Sheng-qi;YAN Zi-zhuo;PENG Hui(Key Laboratory of Safety Control for Bridge Engineering of the Ministry of Education,Changsha University of Science&Technology,Changsha 4101l14,Hunan,China)

机构地区：[1]长沙理工大学桥梁工程安全控制教育部重点实验室,湖南长沙410114

出　　处：《中国公路学报》2024年第4期224-238,共15页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(51708047,51778069);湖南省自然科学基金项目(2023JJ40505);长沙市自然科学基金项目(kq2202207)。

摘　　要：为研究预应力CFRP加固含中心缺陷和双边缘缺陷钢板的疲劳性能,基于团队自主研发的自黏结型预应力CFRP施加装置,开展了2种缺陷类型和3种缺陷长度下预应力CFRP单面加固含缺陷钢板在拉伸循环荷载下的疲劳试验,分析了试件的两阶段预应力,讨论了有限黏结长度下试件的破坏模式、疲劳寿命以及荷载循环次数-钢板表面应变分布规律。利用ABAQUS建立有限元模型,通过计算结果分析了不同疲劳裂纹长度下钢板、CFRP和胶层的应力分布,讨论了胶层刚度的退化规律,探讨了CFRP和预应力对裂纹尖端应力强度因子幅ΔK的影响,并基于裂纹闭合效应的Paris模型预测了缺陷钢板的疲劳寿命。结果表明:有限黏结长度下,自黏结预应力CFRP加固钢板具有更长的光滑断裂面,更长的疲劳裂纹稳定扩展区域,可以较好增加钢板的临界裂纹长度;预应力可以提高CFRP的加固效果,使CFRP承担更多的荷载,改善钢板和胶层应力分布,降低缺陷区域应力集中程度,延缓胶层刚度退化时间;CFRP和预应力可以有效降低裂纹尖端应力强度因子幅ΔK,提高钢板疲劳寿命;基于有限元计算的ΔK和裂纹闭合效应的Paris公式,可以准确预测缺陷钢板的疲劳寿命,预测值与试验值误差小于10%。To the fatigue performance of prestressed CFRP-reinforced steel plates with central defects and double-edge defects. Based on the team's self-developed self-bonding prestressed CFRP application device, fatigue tests of prestressed CFRP single-sided reinforced steel plates with defects under tensile cyclic loading were carried out for two defect types and three defect lengths. In addition, the two-stage prestressing of the specimens was analyzed, and the damage mode, fatigue life and the number of load cycles-plate surface strain distribution law of the specimens under finite bond length were discussed. A finite element model was established using ABAQUS, and the stress distribution of the steel plate, CFRP and adhesive layer under different fatigue crack lengths was analyzed by the calculated results. Furthermore, the degradation law of glue layer stiffness was discussed, the effects of CFRP and pre-stress on the stress intensity factor amplitude ΔK at the crack tip were explored, and the fatigue life of the defective steel plate was predicted based on the Paris model of crack closure effect. The results show that the self-bonded prestressed CFRP-reinforced steel plate has a longer smooth fracture surface and longer stable fatigue crack expansion area under a finite bond length, which can better increase the critical crack length of the steel plate;the prestressing can improve the reinforcement effect of CFRP, make CFRP bear more load, improve the stress distribution of the steel plate and the adhesive layer, reduce the stress concentration in the defective area, and delay the stiffness of the adhesive layer. The CFRP and prestressing can effectively reduce the stress intensity factor amplitude ΔK at the crack tip and improve the fatigue life of steel plates;the Paris formula based on the finite element calculation of ΔK and the crack closure effect can accurately predict the fatigue life of the defective steel plate, and the error between the predicted value and the test value is less than 10%.

关 键 词：桥梁工程 预应力CFRP 有限元分析 缺陷钢板 疲劳性能 应力强度因子 

分 类 号：U443.3[建筑科学—桥梁与隧道工程]