Design and Sizing of a Parametric Structural Model for a UCAV Configuration for Loads and Aeroelastic Analysis

Kurzfassung

The set-up of a parametric structural finite element model for loads and aeroelastic analysis of an unmanned combat air vehicle (UCAV) is presented. The DLR-F19 is a “flying wing” configuration with a geometry based on previous research conducted in the scope of the “Mephisto” project and its predecessors “FaUSST” and “UCAV2010”. While there is a considerable amount of knowledge for conventional configurations, unconventional configurations lack of experience, and data for comparison is rarely available. Using an adequate structural model, the conceptual design becomes more sophisticated and allows for the investigation of physical effects already at an early stage of the design process. Strategies for structural modeling and proper condensation, aero-structure coupling, loads integration, control surface attachment, and the use of composite materials are addressed in this paper. The resulting model is sized for minimum structural weight, taking 216 load cases into account. In addition, a comprehensive loads analysis campaign is conducted and resulting loads are evaluated at defined monitoring stations. Next to maneuver loads, quasi-static gust loads are calculated using the Pratt-formula and compared to results obtained from a dynamic 1-cosine gust simulation. The reasons for higher loads when using the Pratt-formula are discussed. The conclusion is that the Pratt formula is suitable for preliminary sizing of “flying wing” configurations.