TRumpf

Thermoplastic fuselage

In the TRumpf project, novel manufacturing and processing technologies for aircraft fuselage structures based on carbon fiber-reinforced high-performance thermoplastics have been developed.

Joining of carbon fiber-reinforced PEKK by laser in-situ joining: three-layer laminate straps are deposited in a butt strap-design of the monolithic plate; post-consolidation is not required.
© Fraunhofer IWS
Joining of carbon fiber-reinforced PEKK by laser in-situ joining: three-layer laminate straps are deposited in a butt strap-design of the monolithic plate; post-consolidation is not required.
Detailed view of butt strap join.
© Fraunhofer IWS
Detailed view of butt strap join.

Motivation

Research in recent years has led to findings that suggest the use of thermoplastic technologies is advantageous for the construction of structures for civil aircraft, especially fuselage structures. Due to their remeltability, materials based on thermoplastic polymers offer a wide range of advantages in terms of their processability compared to commonly used thermoset materials.


Aims and procedure

In the TRumpf project, technologies were tested and validated for their suitability for manufacturing fuselage structures and then their economic and technological advantages were analyzed in a holistic approach. In the associated sub-project TRumpf-ASS (Automated Surface Protection and Welding Processes for PEKK Fuselage), Fraunhofer IWS scientists developed "laser-in-situ joining", a joining technology that enables continuous laser welding (co-consolidation) of carbon fiber-reinforced thermoplastic laminates to create longitudinal fuselage seams.#

The process is based on already proven automated depositing processes such as Automated Tape Laying (ATL) – but with one decisive difference: With the newly developed technology, pre-consolidated and multi-layer multidirectionally reinforced semi-finished products can be deposited in a single process step. Current manufacturing processes are limited to single-layer unidirectionally reinforced tapes. The ability to deposit semi-finished products at right angles to the implemented fiber directions opens up new manufacturing opportunities for joining complex structures. 


Innovations and perspectives

The technology developed in the project paves the way for new manufacturing options for thermoplastic aircraft fuselage structures, which could drastically reduce the number of additional fasteners required in future aircraft generations. This saving would be reflected in the resulting total weight and thus directly in the form of a reduction in emissions.