Parametric Modeling of a Long-Range Aircraft under Consideration of Engine-Wing Integration

The purpose of this paper is to investigate the influence of the engine position and mass as well as the pylon stiffness on the aeroelastic stability of a long-range wide-body transport aircraft. As reference configuration, DLR’s (German Aerospace Center/Deutsches Zentrum für Luft und Raumfahrt) generic aircraft configuration DLR-D250 is taken. The structural, mass, loads, and optimization models for the reference and a modified configuration with different engine and pylon parameters are set up using DLR’s automatized aeroelastic design process cpacs-MONA. At first, the cpacs-MONA process with its capabilities for parametric modeling of the complete aircraft and in particular the set-up of a generic elastic pylon model is unfolded. Then, the influence of the modified engine-wing parameters on the flight loads of the main wing is examined. The resulting loads are afterward used to structurally optimize the two configurations component wise. Finally, the results of post-cpacs-MONA flutter analyses performed for the two optimized aircraft configurations with the different engine and pylon characteristics are discussed. It is shown that the higher mass and the changed position of the engine slightly increased the flutter speed. Although the lowest flutter speeds for both configurations occur at a flutter phenomenon of the horizontal tail-plane outside of the aeroelastic stability envelope.

Design and Analysis of Composite Window Frame for a Regional Aircraft

This work presents the design and analysis of a thermoplastic composite window frame for integration into a regional aircraft. The main parameters which are investigated include buckling, damage and failure loads of a composite window frame subjected to shear loads repesentative of fuselage skin stress distribution due to flight loads. The attachment of such thermoplastic window frame to a thermoset fuselage skin was investigated including both adhesively bonded interface as well as riveting. Even though the bonded frame did meet the design criteria, its failure was very sudden, and the riveted assembly showed a considerably higher strength and structural integrity. The numerical simulation resulted in failure loads which matched very closely to experimental results.