Mechanical assembly's i.e. epicyclic speed reduction unit, structural anomaly monitoring method for helicopter, involves triggering alert when indicator equal to square root of sum of harmonic amplitudes to power of two exceeds threshold

摘要

The method involves acquiring a measured signal delivered by a vibration sensor during rotation of tour of planet carrier and determining a frequency spectrum of the signal. Meshing harmonic greater than another meshing harmonic is determined for each pair of frequencies emerging from order of 1 to maximal order of row. Monitoring harmonics neighboring the meshing harmonics are selected, and an indicator equal to a square root of a sum of amplitudes of monitoring harmonics to power of 2 is determined. An alert is triggered when the indicator exceeds a preset threshold.