Multilevel analysis of continuous AE from helicopter gearbox

0438589 - ÚT 2015 RIV CZ eng A - Abstract
Chlada, Milan - Převorovský, Zdeněk - Heřmánek, Jan - Krofta, Josef
Multilevel analysis of continuous AE from helicopter gearbox.
11th European Conference on Non-Destructive Testing (ECNDT 2014). Brno: University of Technology, 2014. s. 12. ISBN 978-80-214-5019-6.
[European Conference on Non-Destructive Testing (ECNDT 2014) /11./. 06.10.2014-10.10.2014, Praha]
R&D Projects: GA MPO FR-TI3/755
Institutional support: RVO:61388998
Keywords : structural health monitoring (SHM) * signal processing * acoustic emission (AE) * diagnostics of helicopter gearbox * wavelet analysis * continuous acoustic emission
Subject RIV: JU - Aeronautics, Aerodynamics, Aircrafts

Acoustic Emission (AE) analyzers for the purpose of structural health or condition monitoring should provide longtime continuous signal records with relatively high sampling frequency. Recorded huge data must be analyzed to disclose any faults in monitored processes or structures like e.g. leakages in pressure vessels or defects in rotating machines and gearboxes, etc. Fast and reliable AE signal processing and analyzing methods are required. In this paper we present such analysis of continuous AE recorded during tests of renovated helicopter gearboxes. Four-channel continuous AE recording system with 4 MHz sampling rate was used in the tests performed under variable 'flight' simulation regimes. As an alternative to classical spectrogram analysis, we proposed to use histograms of time intervals between crossings of threshold amplitudes (multilevel counting) in the wavelet decomposition details. Results obtained on long-time records are discussed.
Permanent Link: http://hdl.handle.net/11104/0242489