Abstract Surface patterning has been used to enhance the fracture toughness of adhesive joints. In this study, the effect of the variable bondline thickness introduced by the patterns and the effect of pattern geometry on the fracture behaviour of adhesive joints were analysed. Surface patterns including longitudinal grooves, transverse grooves, dimples and grids were fabricated by means of laser texturing. The patterned surfaces were bonded using a tough structural adhesive and the mode I fracture toughness was measured using the J-integral method. The toughness of the patterned joints was compared with the results from bonding with control surfaces and with grit blasted in combination with chromic acid etched (GB-CAE) surfaces. It was shown that both longitudinal and transverse grooves led to the highest value of toughness. Grid patterns yielded a toughness close to the GB-CAE treatment, both of which were higher than the dimple patterns. It was also shown that the variable bondline thickness due to the existence of surface patterns, which influences the size of the plastic zone, reduced rather than increased the fracture toughness.

中文翻译：

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表面微图案对胶接接头 I 型断裂韧性的影响

摘要 表面图案化已被用于提高胶接接头的断裂韧性。在这项研究中，分析了由图案引入的可变胶层厚度的影响以及图案几何形状对粘合接头断裂行为的影响。通过激光纹理制造包括纵向凹槽、横向凹槽、凹坑和网格的表面图案。图案化表面使用坚韧的结构粘合剂粘合，I 型断裂韧性使用 J 积分法测量。将图案接头的韧性与与控制表面和喷砂结合铬酸蚀刻 (GB-CAE) 表面结合的结果进行比较。结果表明，纵向和横向凹槽都导致最高的韧性值。网格图案产生接近 GB-CAE 处理的韧性，两者都高于凹坑图案。还表明，由于表面图案的存在而导致的可变胶层厚度会影响塑性区的尺寸，从而降低而不是增加断裂韧性。