In the framework of CleanSky2 (CS2)-Large Passenger Aircraft project, a consortium led by Airbus consisting of universities, research centers and industrial partners across Europe investigated various fuselage system, cabin & airframe technologies for commercial aircraft. The goal has been to strongly contribute to the environmental objectives of 20-30% CO2 reduction whereas at the same time performance increase through weight reduction and improved competitiveness through less recurring cost and industrial ramp up capabilities had to be demonstrated. In total, more than 40 different technologies have been further developed by the European consortium consisting of 14 partners in order to finally deliver an 8m large scale flagship in 2024: the Multifunctional Fuselage Demonstrator. Novel fuselage design and built concepts are demonstrated as well as thermoplastic composite material testing & modelling, elementary parts manufacture and assembly for large scale fuselage structures incl. “zero airframe customization” concepts for cabin installation. Final results and major achievements of this European funded program will be presented and discussed in this paper.

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Multi-spot sequential ultrasonic welding is a promising joining technique for thermoplastic composites in an overlap configuration. In the framework of the EU Clean Sky 2 Multi-functional fuselage demonstrator (MFFD) and the lower shell SmarT multifUNctioNal and INteGrated TP fuselage (STUNNING) projects, a robot-based sequential ultrasonic spot welding process has been developed for joining of large thermoplastic structural components, based on process development steps reported in previous work [1]. The technology is being demonstrated on a full-scale thermoplastic composite fuselage section of 8 m length and 4 m shell radius. The fuselage skin is being joined to longitudinal stringers and circumferential frames through welded clips, in the lower shell of the fuselage demonstrator. This paper presents an overview of the robotic sequential welding technology developed at SAM|XL in collaboration with Delft University of Technology and the ongoing sub-assembly process of the fuselage demonstrator, led by GKN Aerospace.@en

Multi-spot sequential ultrasonic welding is a promising joining technique for fibre-reinforced thermoplastic composites structures (TPC). In existing research on the multi-spot sequential ultrasonic welding process, welds are produced through the use of a static table-top welding machine, at a coupon level. However, in order to apply this joining technology to large structures, the welding process needs to be up-scaled through the use of a robotic platform. At the Smart Advanced Manufacturing (SAM|XL) automation field lab and TU Delft Aerospace Engineering, a robotic sequential ultrasonic welding system has been developed. The system consists of a welding end-effector (EEF) equipped with various sensors that enable online process monitoring and control, which can be mounted on an industrial robot arm to perform sequential multi-spot welds. The goal of this study was to assess the welding performance of the ultrasonic welding EEF, which was mounted on an industrial KUKA KR210 R2700 Extra 10-axis robot arm, by comparing it to the performance of welds produced through the static table-top machine. In this study, single and multi-spot welds were produced on thermoplastic composite coupons, based on welding conditions which were defined in a preliminary study. The robot and EEF deflections observed during the welding process were analysed to assess the deviation of the robotic process from the static one. The feedback obtained from the welding equipment in terms of consumed power and tool displacement in both processes was also compared. The weld quality was assessed though single lap shear testing of the welded joints as well as fractography of the failure surface. The results of this study indicate that the developed robotic welding process is quite robust and is capable of producing high-quality sequential welded joints despite significant system deflections observed during the welding process. Slightly lower welded area and weld strength was obtained which can be attributed to the system deflections. Finally, the results indicate that the use of a stiffer robotic platform as well as a stiffer EEF construction will result in better system rigidity and weld spot positioning accuracy, and through this the welding process shows promise for large-scale industrial applications.@en

In this study, the effect of rapid laser heating, which is typical during laser-assisted fiber placement (LAFP), on the micro- and meso- structure of the thermoplastic tape was investigated. Thermoplastic tapes were heated above the melting temperature with different heated lengths (30 and 80 mm and heating times (0.2 and 0.8 s) in a dedicated experimental setup. In-situ and ex-situ characterization techniques were used to observe the differences between the micro- and meso- structure of the tape before and after heating. The experiments resulted in significant changes in the tape structure, namely increased out-of-plane deformation, waviness, arc-length width, roughness, thickness and volumetric void content. This study shows for the first time that a unique deconsolidation behavior takes place during the heating phase of LAFP: the deconsolidation mechanisms are exacerbated by the non-uniform temperature at the tape surface, which is caused by roughness increase and waviness formation.@en