| Helicopter structure and occupants are subject to a severe vibratory environment caused by the cyclic change in angular position, pitch and velocity of a rotor blade relative to the undisturbed incoming air. To improve service life and ride quality rotor vibrations hence must be monitored and controlled. Geometric modal sensors can be tailored to monitor specific vibratory modes by virtue of their geometric design. Because they are distributed over the entire rotor blade, their application relieves problems encountered with discrete sensors. Active Fibre Composites (AFC) can be used as sensor, actuator or can combine both functions in one component. They are manufactured similar to traditional composites and can be built into composite structures to serve as both active and structural component. This thesis develops the geometric sensor shape required for the detection of torsional, flapping and lead-lag modes of vibration of a helicopter rotor blade and determines the mechanical and sensor properties of AFC. |
