Series of diagnostic indicators of gearbox teeth wear in aircraft gas turbine engines

Aircraft gas turbine engine gearboxes are intended for providing optimum rotational speeds for propellers and fans. Wear of the tooth flanks is their key and most dangerous defect. The defect generates vibrations leading to fatigue failure of engine components. Vibration-based diagnostics is the most effective tool of non-destructive testing of the technical condition of rotating machines. This review of the known diagnostic indicators of the defect in question shows the need for its significant expansion. Previously performed researches made it possible to suggest a series of diagnostic indicators of tooth wear for the sun gear satellites couple in the differential reducer of a gas turbine engine. It is shown that the mathematical models of the dependence of the levels of diagnostic indicators on the wear value have both linear and power form. It was found that diagnostic indicators described by power dependences are the closest ones to the model of wear development. It is noted that when selecting diagnostic indicators for operating conditions, the optimal ones should be recognized as those based on the parameters of the current frequency.