Maneuver Loads Calculation with Enhanced Aerodynamics for a UCAV Configuration

摘要

The authors present the development of a software for loads and aeroelastic analysis with aerodynamic enhancements. The background for this effort is the investigation of an unmanned combat air vehicle. 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. In a previous work a structural model was created with DLR's parametric ModGen/Nastran design process. Using that approach, the conceptual design becomes more sophisticated as the structure is sized with typical design load cases. It allows for the investigation of physical effects of maneuver, gust and ground loads or flutter at an early stage of the design process. In this paper, the focus is on static maneuver loads. The analysis is conducted with a commercial software and an in-house software. In contrast to the use of commercial software, the development of the so-called Loads Kernel has the benefit of having full control of the whole procedure of a static maneuver loads calculation. In addition, it allows the implementation of new features. One example is the selective use of aerodynamic forces obtained from CFD. This promises better and more physical results than from fast aerodynamic methods such as the Doublet Lattice Method. In this paper, the Doublet Lattice Method delivers a baseline and is enhanced with results from CFD. It is shown that the aerodynamic characteristics of the DLR-F19 are rather complex and require detailed investigations. The impact on structural loads is significant and an aerodynamic enhancement is absolutely necessary for sophisticated and reliable loads analysis.