Welded thermoplastic composite keel beam demonstrator achieved
Thermoplastic composite keel beam demonstrator, scale 1:1 transverse section and 1 meter in length, completed in Clean Sky 2 KEELBEMAN project. SOURCE | EURECAT.
At the end of February 2020, the project with acronym KEELBEMAN https://cordis.europa.eu/project/id/785435 has successfully concluded. Funded by the European Commission in the framework of the Clean Sky 2 Public-Private Partnership within the EU Horizon 2020 program, the KEELBEMAN project goal was to complete design and manufacturing of a thermoplastic composite keel beam section for an Airbus A320-type aircraft to validate the technology at technology readiness level TRL3.
The KEELBEMAN project addressed the design and manufacture of a full component via a keel beam section demonstrator, using thermoplastic matrix resin reinforced with carbon fiber. The use of manufacturing technologies with significant potential for automation were explored and selected combinations were demonstrated at TRL3.
Under the technical lead of CETMA (Brindisi, Italy), an R&D center highly specialized in composite processing and characterization, a novel continuous compression molding (CCM) process was used to manufacture the skins and the stringers of the keel beam section. CCM is a very fast process, one of the most promising for manufacturing very long thermoplastic composite parts, and CETMA is one of the leading providers of this technology in Europe.
Stiffening ribs were produced using more conventional non-isothermal compression molding by the project coordinator EURECAT, a leading research center located in Barcelona, Spain. Skins, stringers and ribs were assembled using CETMA’s patented induction welding technology.
These manufacturing technologies were complemented by the contributions from two additional KEELBEMAN project partners:
- CT Ingenierie, a French engineering company, carried out the keel beam re-design from metal to composite with no rivets, starting from the metallic baseline defined by Clean Sky 2 topic manager Airbus (Toulouse, France) and defined the architecture and thickness according to calculations from structural and manufacturing process analysis.
- SOFITEC, a leading Spanish TIER 2 supplier for aerostructures, focused on the detailed definition and implementation of ultrasonic nondestructive inspection (NDI) of coupons, subcomponents and the final demonstrator, based on Airbus standards and the particularities of welded thermoplastic composite structures.
A look at the process by which precursor becomes carbon fiber through a careful (and mostly proprietary) manipulation of temperature and tension.
Oven-cured, vacuum-bagged prepregs show promise in production primary structures.
Applications aren't as demanding as airframe composites, but requirements are still exacting — passenger safety is key.