复合材料胶接修补航空铝合金的疲劳性能与损伤监测实验研究

Experimental study on fatigue performance and damage monitoring for aeronautical aluminum alloy adhesively repaired by composite

针对航空铝合金在疲劳载荷作用下易发生疲劳裂纹快速扩展引起突发断裂破坏的问题,采用碳纤维复合材料来胶接修补受损航空铝合金,以提高其疲劳性能。同时,使用红外热成像技术结合数字图像处理,对复合材料与铝合金界面脱粘进行在线监测,尝试建立脱粘缺陷发展与疲劳裂纹扩展之间的关系。进行无修补和有修补受损铝合金试件的疲劳实验对比研究,结果表明:复合材料胶接修补铝合金试件的疲劳寿命比未修补试件提高60%,从实验曲线走势和破坏形态看,可认为复合材料的疲劳性能优于复合材料/铝合金界面的疲劳性能,而界面的疲劳性能优于铝合金的疲劳性能,脱粘缺陷的像素增加与金属的裂纹长度延伸规律一致、高度相关,可以为后续疲劳裂纹扩展监测提供参考。

To address fast growth of fatigue crack and sudden burst fracture of aeronautical aluminum alloy under fatigue loads, this study proposed to use carbon fiber reinforced composite materials to repair damaged aluminum alloy to improve its fatigue performance. At the same time, infrared thermal imaging technology with digital image processing was employed to online monitor the interfacial debonding, and tried to establish the correlation of the fatigue crack growth and the interfacial debonding. The research on fatigue experiment contrasted with un-repair and repair damaged aluminum alloy specimen. The results show that the fatigue life of the specimen adhesively repaired by composite is 60% longer than that of the un-repaired specimen; the fatigue performance of the composite is better than that of the bonding interface, and the fatigue performance of the bonding interface is better than that of the aluminum alloy; the number of pixels of the debonding defect increase with the growth of crack length, and they are highly correlated. The finding provides a reference for further fatigue crack growth monitoring.