Manufacturing and reinforcement technologies for the next generation aircraft rear-end

Abstract

Caused by increasing mobility of more and more people, the demand for reducing CO2 emissions emitted by civil aviation increases constantly. Foreseeable CO2 restrictions for future aircraft require lightweight designs, new engine concepts and likely disruptive new aircraft configurations to prevent growing ecological footprints. Beside these ecologic requirements, the mobility increase dictates to develop technologies for low-cost, high rate production. Therefore, the Clean Sky 2 research program supports finding answers for these challenging, sometimes conflicting requirements. Different promising aircraft concepts (hybrid electric propulsion, forward swept wings or tails) require new designs of the a/c rear end. Design drivers are the auxiliary power unit (APU) and its arrangement as well as engine integration and tail surface arrangement. Additionally, low cost manufacturing technologies for lightweight materials will be addressed in order to increase the production rate and the fuel efficiency due to mass reduction. 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. Meanwhile, two large high velocity impact test campaigns were conducted on a range of different materials, including a reference material. One test campaign was conducted at DLR Stuttgart and the second test campaign took place at ONERA Lille (France). A further test campaign is foreseen this year. Besides the security relevant high velocity impact test, real-time damage assessment technologies are developed supporting the maintenance of aircraft and enables a flexible maintenance concept. The first development step towards high-rate thermoplastic fiber lay-up is the approach based on the use of a xenon heating lamp. Xenon heating requires hardly any security efforts and is therefore interesting for flexible low cost manufacturing. First manufacturing trials with this technology at DLR Stade reveal the control parameters necessary to adjust the nip point temperature. Furthermore, the test samples show a good consolidation in the microsection. The final paper will discuss the benefits and drawbacks of the investigated advanced impact materials and their effects on the initially mentioned environmental targets. Furthermore, the thermoplastic lay-up technology will be assessed with respect to the manufacturing targets of 100 a/c a month.