Manufacturing and reinforcement technologies for the next generation aircraft rear end: part 2

Nowadays, the decarbonization of civil aviation is the major challenge for the aviation industry. Besides the use of alternative green fuels being significantly more expensive, also every aircraft component has to be optimized such that the fuel consumption of the aircraft achieves a minimum. All these efforts have to consider that the European aviation industry have to sell aircrafts at a reasonable price compared to their competitors. In the European research program “Large Passenger Aircraft” as part of the Clean Sky 2 initiative, an advanced rear-end concept is investigated. The advanced rear-end project aiming for a forward swept tail configuration which has several aerodynamic and configurational benefits. At the same time it is developing low-cost and optimal lightweight manufacturing technologies to ensure the competitiveness of future aircraft. The German aerospace center (DLR) supports the investigations towards a future rear end with two research streams: 1.) Simulation tools for the design of lightweight and cost efficient reinforcements required at the aircraft rear end and 2.) Thermoplastic manufacturing technologies for complex and double curved rear end structures. In this presentation, the on-going work since the last DLRK presentation in 2019 is presented. During the last two years, a third high velocity impact test campaign with a ballistic material is conducted. It is shown that the Zylon material has superior impact resistance compared to the formerly tested aluminum and carbon materials. Besides the safety relevant impact studies, a damage assessment simulation tool chain is developed which will support lightweight compliant design of carbon fiber reinforced plastics. This toolchain will furthermore be applied for the maintenance process of future aircraft. Additionally, the manufacturing technology development for thermoplastic material is presented. DLR investigates a Xenon flash lamp heating source to lay up low melt PAEK material. This heating method is an alternative to laser heating and is currently under investigation with respect to lay up speeds, critical curvature, ramps and laminate thickness which are present at the rear-end. Furthermore, the automated lay up of a lightning strike protection (LSP) layer is investigated. Therefore, a LSP material is developed that is processable with a automated fiber placement head on a robot. Also, different designs for the lightning strike layer are studied which offer a weight saving potential compared to the state of the art. In the next project period, the developed impact simulation tools will feed the virtual demonstration of the advanced rear-end enabling the forward shift of the auxiliary power unit. Furthermore, a full-scale part of the rear-end lower shell including all the aforementioned challenges will be manufactured with the thermoplastic technologies