Colloquium: Nigel van Nierop (ASM)

The goal of the project was to produce slotted single-lap shear specimens using continuous ultrasonic welding, which had not been done before. These aim to provide more reliable lap shear strengths than currently used coupons due to increased assembly stiffness and eliminated squeeze-out. By increasing the weld width and stacking smaller rotated adherends, fully welded coupons could be extracted and subsequently slotted. However, high-quality welds were not yet obtained consistently due to pre-heating of the adherends, resulting in overheating during about the second half of these welds. The produced slotted coupons showed the viability of using this configuration, the best achieving 1% under-welding and 90% of the co-consolidated slotted coupon reference lap shear strength, despite not being fully optimized. However, slot precision is essential. In contrast, welded conventional coupons likely yield non-conservative strengths, reaching 109% of the reference, possibly due to the squeeze-out and adherend geometrical distortions resulting from welding.

Supervisor: Irene Fernandez Villegas