Modeling and Control Methods for Future Vertical Lift Rotorcraft Fatigue Reduction

Rotorcraft experience vibratory loads due to the constantly varying airloads under all flight conditions. Maximizing the fatigue life of their structural components is a vital factor for sustained operations with low-maintenance. Most existing fatigue analysis methods are empirical-based and, hence, are limited for use in investigating the effects of maneuvering flight as well as for exploring modern control methods (e.g., on-blade controls) for alleviating fatigue. ART proposes to develop rotorcraft loads analysis methods with fatigue damage estimation and fatigue reduction controllers to augment a technical base toward the goal of "zero-maintenance" (or minimum maintenance) for significantly reduced operational costs and enhanced flight safety. The innovations of this proposal are 1) the state-of-the-art rotorcraft loads analysis methods, 2) the tool that couples the analysis with both the fatigue damage detection sensors and the damage estimation methods, and 3) the development of the fatigue mitigation controls. The feasibility of the proposed methods will be demonstrated through the Phase I development.