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Accession Number ADA584696
Title Prognostics and Diagnostics of Rotorcraft Bearings.
Publication Date Sep 2011
Media Count 9p
Personal Author A. Ghoshal D. Le M. A. Haile
Abstract This paper presents a diagnostic and prognostic approach for rotorcraft bearing health monitoring using the Hilbert-Huang Transform (HHT). The HHT transforms a raw vibration data into in a two-dimensional time-frequency domain by extracting instantaneous frequency components within the signal through an empirical mode decomposition EMD process. EMD transforms the complex vibration signal into simple oscillatory modes called intrinsic mode functions (IMFs). Since the IMFs are obtained based on the local characteristic time scale of the data, they can be used to analyze the nonlinear and nonstationary bearing degradation processes. In performing diagnostic decisions, the work presented here uses the energy ratios of the highest two intrinsic modes and the respective marginal frequencies as condition indicative features. The approach has been tested using experimental data obtained from seeded spall and corrosion tests on AH-64 Apache hanger bearings.
Keywords Bearings
Emp(Empirical mode decomposition)
Frequency domain
Hht(Hilbert-huang transform)
Imf(Intrinsic mode functions)
Integral transforms
Rotary wing aircraft
Stft(Short-time fourier transforms)
Time domain
Wavelet transforms
Wt(Wavelet transforms)

Source Agency Non Paid ADAS
NTIS Subject Category 51C - Aircraft
72B - Algebra, Analysis, Geometry, & Mathematical Logic
41J - Tooling, Machinery, & Tools
46E - Structural Mechanics
Corporate Author Army Research Lab., Aberdeen Proving Ground, MD.
Document Type Technical report
Title Note Conference paper.
NTIS Issue Number 1403
Contract Number N/A

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