海洋大气环境对CFRP-钢界面粘结性能的影响

Effect of marine atmosphere on the bond behaviour of CFRP-steel interface

为研究长期海洋大气环境作用对碳纤维增强树脂复合材料(CFRP)-钢界面粘结性能的影响,设计并制作了36个CFRP-钢板双搭接试件,采用盐雾沉降量1~2 mL/80(cm^(2)·h)的盐雾箱来模拟海洋大气环境。对试件进行了疲劳加载后的静力拉伸试验,分析了环境作用时间(30、180、360天)、长期持续荷载和硅烷表面处理方式对CFRP-钢界面破坏模式和承载力的影响。研究结果表明:随着海洋大气环境作用时间增加,CFRP-钢双面搭接节点由胶层内破坏伴随CFRP层离破坏逐渐向钢-胶界面粘结失效转变。暴露360天后极限承载力最大下降了15.72%。硅烷表面处理对CFRP-钢界面耐久性提升作用较小。持续荷载导致短期环境作用下(30天)极限承载力下降了18.39%,但对长期环境作用影响很小,高应力预加疲劳导致CFRP-钢界面极限承载力最大下降了26.6%。采用Hart-Smith模型对CFRP-钢界面极限承载力进行计算,发现长期环境作用后的承载力预测值和试验值误差超过了30%。在考虑破坏模式变化对界面极限承载力的影响下进行了修正,将误差减小到最大为14.04%。

To investigate the effect of long-term marine atmosphere on the bond behaviour of carbon fibre reinforced polymer(CFRP)-steel interface,36 CFRP-steel plate double-lap joint specimens were designed and fabricated.A salt spray box with a salt spray deposition volume of 1-2 mL/80(cm^(2)·h)was used to simulate the marine atmospheric environment.Fatigue and static tensile tests were carried out successively.The effects of environmental exposure time(30,180,360 days),long-term sustained load and silane surface treatment on the failure mode and ultimate bearing capacity of the CFRP-steel interface were analyzed.The results show that the failure mode of CFRP-steel interface gradually changes from cohesive failure and CFRP delamination to steel-adhesive interfacial debonding with the increase of exposure time to marine atmosphere.The long-term marine atmosphere effects cause significant degradation of the CFRP-steel interface bond performance,and the ultimate bearing capacity decreases by a maximum of 15.72%after 360 days of exposure.Silane surface treatment has little effect on improving the durability of CFRP-steel interface.The sustained load causes the ultimate bearing capacity to decrease by 18.39%under the short-term environmental action(30 days)while having little effect on the long-term environmental action.The high stress preload fatigue resulted in a maximum decrease of 26.6%in the ultimate bearing capacity.The Hart-Smith model was used to calculate the ultimate bearing capacity of the CFRP-steel interface,and it is found that the error between the predicted and experimental values of ultimate bearing capacity after long-term environmental action exceeds 30%.After considering the influence of failure mode change on the ultimate bearing capacity,the error is reduced to a maximum of 14.04%.