Author(s)

N. M. Saeed & A. S. K. Kwan

Abstract

Morphing structures have great importance in numerous engineering applications, and have significant potential in the aerospace industry. An aircraft structure has different aerodynamic requirements for different stages of flight, and an optimal aircraft structure would also have different optimal shapes and geometry for these different requirements. A morphing structure has capability to provide for variable geometry. In this research, suitable morphing aerofoil structures have been found, as alternatives to the traditional aerofoil, and they provide larger lift (CL) and smaller drag (CD) coefficients. The morphing aerofoil structures proposed are achieved via series of interconnected, curved, single-actuator pantographs, with standard aerofoil NACA2415 chosen as the base-shape for comparative work. Two configurations have been studied in depth. The first consists of a small number of big pantographic elements, while the second consists of a large number of small pantograph elements. Results show that the second morphing structure exhibits a wider range of CL and CD than achievable by the first, and also by the standard NACA2415 with flaps. Taking the place of the traditional hinged control by the morphing aerofoil with smaller drag was shown to produce bigger lift. In addition, it was found that the morphing aerofoil can decrease the drag by more than 18%, especially in the starting stages of morphing. Furthermore, two useful and relatively simple methods have been presented in this paper, which provide a direct method for calculating required morphing shape displacements and calculating set of length actuations for bar assembly to adjust shape imperfection. This paper will cover the details of the geometry of the morphing structures and the aerodynamic properties of the different shapes during the morphing process. Keywords: morphing structure, morphing aerofoil, NACA aerofoil, aerodynamic characteristics, shape adjustment.

Keywords

morphing structure, morphing aerofoil, NACA aerofoil, aerodynamiccharacteristics, shape adjustment.