Closed Loop Approach to Structural Health Monitoring of Critical Rotorcraft Components

We present a model-based structural health monitoring approach to mitigate fatigue damage of critical rotorcraft components in real time. The overall concept is demonstrated with aerodynamic loads for a utility helicopter similar to the UH-60 Black Hawk and a structural model of the main rotor's pitch link. The potential of reducing computational costs associated with modeling by utilizing a quasi-static analysis was considered in this study, however, it was concluded that a dynamic analysis was indeed necessary to accurately capture the inertial effects of the vehicle. Maximum stress results extracted from the model can be sent to a controller to apply a load alleviation control scheme to appropriately modify the input to the rotorcraft controls and reduce air loads to the vehicle. The modeling, analysis, and load alleviation process were also automated. We also completed an investigation into the impact of vehicle control input parameters on stress experienced by the component.