Defect-tolerance in adhesive joints with patterned interfaces

The mandatory emission reduction schemes established by national governments across the globe induced an irreversible shift toward low-emission mobility in the strategic field of transportation. Priority has been given to weight reduction through the clever use of a consistent mix of materials, such as aluminum alloys and fiber reinforced composites. However, joining still represents one of the industrialization hurdles that prevents to fully benefit from lightweight materials. Adhesive bonding already surfaced as a potential candidate technology that can supplement or replace existing techniques. Yet, the transition from classical joining techniques to fully adhesive bonded lightweight structures has been hampered by the relative paucity of highly controllable, reproducible, flexible and environmentally friendly surface preparation methods. Moreover, the lack of safety measures that can cope with potential disbonds, either arising in service or due to improper manufacturing, is causing additional concerns. In this work the authors will highlight a toughening strategy which can support the development of damage tolerant adhesive joints. The approach presented largely leverages on the deployment of highly controllable and reproducible surface pre-treatments using pulsed laser irradiation. The discussion around the associated beneficial effects on joint strength and bond toughness will be supported by the analysis of our most recent experimental and numerical results.