5. Structural Health Monitoring of Composite Helicopter Rotor

Chapter 5 illustrates the genetic fuzzy system for health monitoring of a composite helicopter rotor in forward flight. The rotor is the most important component of the helicopter, and its health is critical for helicopter performance and control. Progressive damage accumulation is considered in the composite material. This damage model considers matrix cracking as the first damage type, followed by debonding/delamination, and finally fiber breakage. The damaged helicopter rotor is modeled using a finite element simulation which solves the rotor blade equations and vehicle trim equations. This aeroelastic simulation provides the blade response, blade and hub loads, strains, etc., for a damaged composite helicopter rotor in forward flight. The genetic fuzzy system is developed and tested for this helicopter rotor health monitoring problem. Different combinations of measurements are considered, and their advantages and shortcomings are evaluated. Finally, a life prediction approach is developed based on phenomenological damage growth models, and the genetic fuzzy system is illustrated for damage detection as well as life prediction for a helicopter rotor.