SBIR-STTR Award

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.

Rotorcraft undergo constant vibratory excitation due to unsteady airloads resulting from the rotor rotation even in steady state flight conditions. These vibratory loads are a challenging aspect in terms of both operational cost and flight safety. This research aims at developing 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 research emphasizes the development of a simulation based predictive capability by coupling a state-of-the-art rotorcraft loads prediction tool with fatigue damage analysis to aid in the development of fatigue mitigation controls. Extensive simulation testing will be conducted to evaluate the effectiveness of the fatigue mitigation controller and its impact on the primary flight controls to ensure that both the flight performance and flying qualities are preserved.