CFRP-OFBG板加固损伤钢梁抗弯疲劳试验及其寿命预测研究  

Study on flexural fatigue test and life prediction of damaged steel beams strengthened by CFRP⁃OFBG plate

作　　者：邓朗妮[1] 李太升 刘阳[1] 廖羚[1] 钟锰军 李华 DENG Langni;LI Taisheng;LIU Yang;LIAO Ling;ZHONG Mengjun;LI Hua(College of Civil and Architectural Engineering,Guangxi University of Science and Technology,Liuzhou 545006,China)

机构地区：[1]广西科技大学土木建筑工程学院,柳州545006

出　　处：《建筑结构》2024年第3期141-146,102,共7页Building Structure

基　　金：国家自然科学基金地区基金项目(51568008)。

摘　　要：为研究采用碳纤维增强复合材料(CFRP)加固后钢梁的疲劳性能,采用自主研发的具有自监测性能的智能碳纤维-光纤光栅板(CFRP-OFBG板)加固受损钢梁,在完成常幅荷载四点弯曲疲劳试验的基础上,研究不同应力幅作用下CFRP-OFBG板加固钢梁的疲劳性能。借助有限元方法,建立“三维实体”有限元模型,结合J积分计算方法求解得到加固钢梁裂纹尖端的应力强度因子,基于线弹性断裂力学理论建立疲劳裂纹扩展模型,对CFRP-OFBG板加固钢梁的疲劳裂纹扩展寿命进行预测。研究表明:CFRP-OFBG板的加固作用可有效提高受损钢梁的疲劳寿命,延缓裂纹扩展速率,改善裂纹尖端的受力状态,降低裂纹尖端的应力强度因子;在循环荷载作用下,CFRP-OFBG板加固试件的疲劳寿命均随着应力幅的增大呈现递减趋势。将试验结果与预测结果相比较,发现加固试件疲劳寿命预测值比试验值略高,分析认为,这主要是因为在有限元模拟时没有考虑到试验中CFRP-OFBG板的局部剥离。In order to study the fatigue properties of steel beams strengthened by carbon fiber reinforced plastics(CFRP),the self⁃developed smart carbon fiber reinforced plastics⁃optical fiber bragg gratings plate(CFRP⁃OFBG plate)plate with self⁃monitoring performance was adoptd to strengthen the damaged steel beams.Based on the completion of the four⁃point bending fatigue test under constant amplitude load,the fatigue properties of steel beams strengthened by CFRP⁃OFBG plate under different stress amplitudes were studied.The“three⁃dimensional solid”finite element model was established by using the finite element method,and the stress intensity factor at the crack tip of the reinforced steel beam was solved by theJ integral calculation method.The fatigue crack propagation model was established based on the linear elastic fracture mechanics theory,and the fatigue crack propagation life of the steel beam strengthened by CFRP⁃OFBG plate was predicted.The results show that the reinforcement effect of CFRP⁃OFBG plate can effectively improve the fatigue life of the damaged steel beam,delay the crack growth rate,improve the stress state at the crack tip,and reduce the stress intensity factor at the crack tip.Under cyclic loading,the fatigue life of specimens strengthened by CFRP⁃OFBG plates decreases with the increase of stress amplitude.Comparing the test results with the predicted results,it was found that the predicted values of fatigue life of the reinforced specimens were slightly higher than the test values,which was analyzed to be mainly due to the fact that the local peeling of the CFRP⁃OFBG plate in the tests was not taken into account in the finite element simulations.

关 键 词：钢梁 加固 CFRP-OFBG板 疲劳裂纹扩展 寿命预测 

分 类 号：TU391[建筑科学—结构工程]