Abstract The over-ply covering the bondline in scarf-repaired laminates can avoid direct exposure of the adhesive to moisture environment which would decrease the properties of the adhesive. The effect of the over-ply on moisture absorption behavior of scarf-repaired composite laminate was studied in this paper. 3D finite element models (FEMs) of scarf-repaired laminates with and without over-ply were established to simulate the moisture absorption behavior and verified by experimental results. Then these models were used to investigate the effects of some factors, including over-ply type, configuration, direction and number, on moisture absorption behavior of the repaired structures, especially of the adhesive. The results show that the over-ply can efficiently decelerate moisture absorption of the adhesive and delay the time of its moisture absorption equilibrium. Over-ply type has effect on moisture absorption of the adhesive. Woven over-ply is more effective to protect the adhesive in repaired laminates from moisture absorption than unidirectional over-ply. For the laminates with only large-circle bonding surface covered, over-ply lap length, configuration and direction are not very important parameters to affect the moisture absorption.

中文翻译：

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外层对围巾修复复合层压板吸湿性能的影响

摘要 在围巾修复的层压板中覆盖粘合层的外层可以避免粘合剂直接暴露在潮湿环境中，这会降低粘合剂的性能。本文研究了外层对围巾修复复合层压板吸湿行为的影响。建立了有和没有覆盖层的围巾修复层压板的 3D 有限元模型 (FEM) 来模拟吸湿行为并通过实验结果进行验证。然后使用这些模型研究了一些因素，包括覆层类型、配置、方向和数量对修复结构，特别是粘合剂的吸湿行为的影响。结果表明，外层可以有效地减缓粘合剂的吸湿速度，并延迟其吸湿平衡的时间。Overply 类型对粘合剂的吸湿性有影响。与单向覆盖层相比，编织覆盖层更有效地保护修复后的层压板中的粘合剂免受水分吸收。对于仅覆盖大圆粘合面的层压板，覆盖层搭接长度、配置和方向不是影响吸湿性的非常重要的参数。