Fault Diagnosis of Wheel Flat Using Empirical Mode Decomposition-Hilbert Envelope Spectrum

Table 3

Effects of flat length on Hilbert envelope spectrum amplitude with dual flats.

Flat length; (mm)	Actual frequency; (Hz)	Amplitude of IMF1Hilbert envelope spectrum; (m/s^2)	Sum of Hilbert envelope spectrum amplitude of IMF1-IMF3 (m/s^2)
10	9.658	0.2054	0.4778
20	9.658	0.6932	1.1056
30	9.661	1.1848	2.0216
40	9.658	1.9579	3.5301
50	9.658	2.7344	5.6904