Recently, signal processing methods are shown to be
successful while diagnosing faults in mechanical systems, using noise or
vibration data. In this study, two
different faulty air disc brakes; noisy and less noisy ones are investigated
using Wavelet Synchrosqueezed Transform on audio recordings. The difference
between two types are shown in scalogram and also verified by a quantitative
measure of entropy. The audio recording has been carried out by using two
identical microphones sited on the brakes via data acquisition unit at a
sampling rate of 20 kHz, 16-bit resolution and these data are analyzed in
MATLAB software. The average of the entropy values of faulty and non-faulty
brakes were found to be 0.98 and 0.65, respectively. Therefore, it has been
concluded that, the entropy could be used as a distinguishing tool to
discriminate the faults.