first investigation into identifying challenges for up-scaling, proposing and testing new ultrasonic welding concepts and utilization of the best concept in the design of a sequential welding procedure for a practical application.

The aerospace industry is looldng to reduce their enviromnental impact through projects like the Clean Sky Joint Technology Initiative. Two measures to help achieve this goal are to reduce the aircraft weight so the emissions during flight decrease and to increase the manufacturing efficiency. Composites often offer lighter solutions and new manufacturing possibilities. Especially thermoplastic composites, which have the ability to melt and fuse, offer many interesting possibihties in manufactming and structural integration. Ultrasonic welding (USW) is a fusion bonding process which utilizes the ability of thermoplastic composites to form a fusion bond. USW has extremely short process cycles, does not introduce any foreign materials regardless of
the composition of the samples to be welded, is energy efficient and has the ability to be on-line monitored, providing joint quality information during welding. With USW it is possible to create fast, clean and consistent welds in lap shear samples. However the step to up-scaling of the process has yet to be made. If found possible, USW might contribute to clean joints with strongly reduced processing times and therefore reduce the environmental impact...