The effect of the pre-bond contamination with fingerprint (FP), both during the production and the application of adhesively bonded patch repairs on composite aircraft parts, and the cumulative effect of fingerprint and hygrothermal ageing on the fracture toughness of carbon fiber reinforced plastic (CFRP) bonded joints are experimentally investigated. To this end, mode I and mode II fracture toughness tests were conducted on FP contaminated coupons and mode II fracture toughness tests on FP contaminated and aged coupons. The artificial FP was supposed to mimic the accidentally applied fingerprints on the CFRP adherent and was applied on the adherent in the size of a human thumb. The two investigated FP formulations consisted of an artificial hand perspiration solution for the production scenario, and of Skydrol hydraulic-oil for the repair scenario. Three levels of contamination with FP were considered for each scenario. The hygrothermal ageing conditions applied until moisture saturation achieved were 70 °C/85% RH. Prior to bonding, the CFRP adherent surfaces were inspected using full-scale monitoring with optically stimulated electron emission (OSEE), an extended nondestructive testing method, in order to analyze the physicochemical variations at the contaminated surface of the adherents before bonding. The ANOVA statistical method was used to assist the evaluation of the results and the deduction or reliable conclusions. The results revealed that the pre-bond FP contamination of the adherents leads to the reduction of the fracture toughness of the CFRP bonded joints. After-bond hygrothermal ageing under the prescribed conditions had no significant influence on the moisture absorption and load carrying capacity of the joint. However, it influenced the bondline integrity as it led to a significant reduction of the fracture toughness of the joint. The effect of the combination of pre-bond contamination and after-bond hygrothermal ageing is more severe than the two separate effects.

复合材料飞机零件的生产过程和粘合修补程序的修复过程中，粘结前的指纹污染（FP）的影响，以及指纹和湿热老化对碳纤维增强塑料断裂韧性的累积影响（ CFRP）粘结接头进行了实验研究。为此，对FP污染的试样进行了I型和II型断裂韧性测试，对FP污染和老化的试样进行了II型断裂韧性测试。人造FP应该模仿CFRP粘附剂上意外施加的指纹，并以人的拇指大小施加到粘附剂上。两种被调查的FP配方均包含针对生产场景的人工手汗解决方案，和Skydrol液压油进行维修。对于每种情况，均考虑了FP的三种污染水平。直至达到水分饱和为止的湿热老化条件为70°C / 85％RH。粘结之前，使用扩展的无损检测方法光学刺激电子发射（OSEE）进行全面监控，以检查CFRP粘结表面，以便在粘结之前分析粘结物受污染表面的物理化学变化。使用ANOVA统计方法来协助评估结果以及推论或得出可靠的结论。结果表明，粘结前的FP污染粘附剂会导致CFRP粘结接头的断裂韧性降低。规定条件下的粘结后湿热老化对接缝的吸湿性和承重能力没有显着影响。但是，它影响粘合线的完整性，因为它导致接头的断裂韧性大大降低。结合前的污染和结合后的湿热老化的影响比两种单独的影响更为严重。