Morphing Unmanned Aerial Vehicles

The performance and dynamic efficiency of an aircraft are significantly influenced by the aircraft shape and configuration. Therefore, the wing which is an important element in the aircraft load response in terms of drag and lift has been given increasing attention through morphing technology. Several governmental programs and academic research projects on morphing aircraft have investigated methods of efficiently changing the wing geometric characteristics in-flight. The present thesis reviews the current knowledge on wing morphing concepts and investigates the type of methods that can be used to model morphing structures. This review includes the principles of the morphing concept, realization of a morphing structure, aspects of morphing structure design, current methods to model morphing structures, challenges, and the perspectives of the morphing UAVs. It concludes that the wing cover skins must possess a high degree of deformability; but they must be able to maintain their shape and structural integrity under the compression, tension, shear and bending characteristics of aerodynamic and flight loads including the effects of added masses. In order to meet these requirements, thermoplastic elastomers and shape memory polymers are suggested as good candidate materials for smart skins. Nevertheless, an excessively flexible skin is exposed to the hazard of sagging under pressure loads. It is suggested that bio-inspired micro air vehicles based on bat wing structure will gain intensive attention since such a structure prossesses a high flexibility with anisotropy and non-linear elasticity