Untersuchung adaptiver Konzepte zur Reduktion von Hubschraubervibrationen, zur Minderung des Hubschrauberlaerms und zur Steigerung der aerodynamischen Effizienz

By applying adaptronics to helicopters, i.e. by use of self-adapting structural components, noise can be suppressed, vibration reduced and aerodynamic efficiency increased. This thesis investigates two concepts, the adaptive blade root and the adaptive blade tip, allowing direct adaptive shape control of the main rotor areas that are the main sources of helicopter noise and vibration. Both concepts are based on the introduction of a local twist into the rotor blades. Since non-stationary helicopter aerodynamics and their interaction with the elastic helicopter structure are the main sources for flight envelope boundaries as well as vibration and noise, the comprehension of aerodynamics is essential to effectively influence local airflow conditions and finally evaluate the investigated concepts. With respect to these relations the adaptive blade root and the adaptive blade tip are described and evaluated. The adaptive blade root represents a torsional actuator integrated in the rotor blade root that mainly introduces rigid body blade torsion. A torsional actuator integrated in the rotor blade tip is realized by the adaptive blade tip. This concept influences the blade twist distribution close to the blade tip and leads to higher aerodynamic efficiency due to this approach. (orig.)SIGLEAvailable from TIB Hannover: RN 437(98-12) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman