 Aircraft are still being assembled, primarily using rivets and other mechanical fasteners to discreetly join all of the parts together. But this joining mechanism is inefficient as it concentrates load transfer to individual fastener locations. Joining methods which more evenly distribute load transfer, such as adhesive bonding, would be far more structurally efficient and thus result in lighter weight and more efficient aircraft. So why are we not widely using adhesive bonding to assemble aircraft? One of the major barriers to the widespread application of adhesive bonding is that of ensuring the quality and strength of the bond. You may have inadvertently encountered this problem yourself if you are an avid user of sticky notes as I am. If you put a number of sticky notes on a wall, being sure to try and repeat this process in the same way for each note. You may encounter over time that one or more of the notes falls down. The nature and complexity of the bonding process results in a risk that some bonds may form that appear to be intact but are in fact weaker than expected. This risk is difficult to accept in aerospace structures, particularly if their failure would be catastrophic to the aircraft. As a result, we continue to use the more inefficient but less risky joining method. In my master's research project within the aerospace structure and materials department, I am examining ways of mitigating the risk in bonded joints. Numerous researchers have attempted to tackle this problem through stringent process control to eliminate the risk of weak bonds from forming during the production. But this approach has not yet been able to eliminate the risk entirely. As a result, I have decided to adopt an alternative approach to accept that weak bonds can occur and look at adding features to the bonded joint itself that will arrest the growth of weak bonds preventing catastrophic failure. My research builds on the work of the European project called BOPUX that investigated numerous bondline features that could be used as damage arresting features. This project identified a simple bold as the easiest and most effective design feature to arrest a disbond and demonstrated its effectiveness in composite structures. My work looks at the extension of this concept to metal and hyper-metal composite structures. The first aim of my work was to better understand the key mechanisms for damage arrest introduced by the bold itself. The bold both clamps the parts together, providing mode 1 suppression of the damage and introduces an additional load path for load transfer, providing mode 2 suppression of the damage. To isolate these effects, I designed a clamping fixture that could apply the predefined clamping load across the entire width of a simple test coupon, allowing the effectiveness of mode 1 suppression to be studied in isolation. The second aim of my work was to understand potential risks associated with arresting a disbond in a bonded metal or hybrid structure. If we look at what happens when we arrest a disbond in a bonded joint, we actually fixed the position of a stress concentration associated with the edge of the disbond. Because this edge no longer moves, the stress concentration can lead to fatigue crack initiation within a metal or hybrid structure that could create an even bigger problem than the original disbond. To investigate this, I have developed a simple analytical model to investigate different disbond arrest features that would slow down but not completely arrest a disbond so that the time to detect that damage could be maximized without risking the initiation of a new fatigue crack damage. Through my work, we are gaining a better understanding of the mechanisms of arrest and the desired arresting behavior that would enable the safe detection and repair of bond line damages over the life of an aircraft. This will perhaps enable the tailoring of the fasten design for this damage arresting function and enable more weight efficient bonded aircraft structures without a sacrifice in safety or reliability. If you are interested to know more about my work, my thesis is publicly available on the TU Delphi repository and can be accessed with the following QR code.