TOWARD DEVELOPMENT OF AN INTELLIGENT ROTOR SYSTEM

The helicopter rotor system is a flight critical system with no redundant load path and rotor components require high maintenance. To improve safety and reliability and reduce maintenance costs for rotrocraft, an intelligent rotor system is in the beginning stages of development. The function of the intelligent system is health and usage monitoring, which is to diagnose small scale damage to the flexbeam and rotor blade, and to monitor and control loads. The challenges in designing the damage detection system are related to the operating conditions of the flexbeam/rotor. These conditions include significant aerodynamic and external damping in bending and torsion modes, moderate nonlinearities in the system, large dynamic loads in the rotor, and difficulty in actuating pure interrogation signals in the airborne (rotating blades) condition. The approaches taken for health and load monitoring are discussed in this paper. The approaches include Resonant Comparison, Wave Propagation and Acoustic Emission.