湿度对共胶接复合材料层间断裂韧性的影响机制

Mechanism of Influence of Humidity on Interlayer Fracture Toughness of Co-Bonded Composites

前期研究表明,已固化的复合材料层板在存放过程中会吸收环境中的水分,继而对复合材料的胶接性能造成影响,但湿度影响复合材料共胶接性能的机制尚不清楚。通过I型层间断裂韧性(GIC)表征共胶接性能,将三种有代表性的T800级碳纤维预浸料在不同吸湿条件下进行处理后,分别与两种胶膜进行胶接,测试复合材料共胶接性能,探究不同预浸料层板的吸湿差异及后续共胶接性能的差异,最后采用扫描电镜观察试验件的断面形貌,探讨待胶接板吸湿后,共胶接复合材料胶接性能下降的原因。试验结果表明:三种材料层板的吸湿率与时间的开方呈近似线性关系,满足菲克定律,但吸湿速率和吸湿量有所不同;吸湿后三种复合材料的GIC发生不同程度的下降,且两种胶膜匹配下的复合材料胶接性能下降程度有差异。通过扫描电镜观察,分析得到待胶接板吸湿后共胶接复合材料的内部结构变化,探究了不同材料和不同胶膜匹配时胶接试验件的失效机制。

Previous studies have shown that cured composite laminates absorb moisture from the environ-ment during storage,which in turn affects the bonding performance of composite materials.However,the mechanism by which humidity affects the co-bonding performance of composites is still unclear.The co-bonding performance through I-type fracture toughness(GIC)was characterized.Three representative T800 grade carbon fiber prepregs were treated under different moisture absorption conditions and then bonded with two types of adhesive films to test the co-bonding performance of composites.The moisture absorption differences of different prepreg layers and the subsequent co-bonding performance differences were ex-plored.Finally,scanning electron microscopy was used to observe the cross-sectional morphology of the test piece and explore the reasons for the decrease in bonding performance of the co-bonding composites af-ter the moisture absorption of the bonding plate.The experimental results show that the moisture absorption rate of the three material laminates is approximately linearly related to the square root of time,satisfies Fick's law,but the moisture absorption rate and amount are different.After moisture absorption,the GIC of the three composites decreases to varying degrees,and there was a difference in the degree of decrease in the bonding performance of the composites under the matching of the two adhesive films.By observing with scanning electron microscopy,the internal structural changes of the co-bonding composites after the mois-ture absorption of the bonding plate were analyzed,and the failure mechanism of the bonding test piece un-der different materials and different adhesive film matching was explored.