Page 13 - Vibrations-2

Achieving efficiency and minimising vibration requires the

detection of these faults and imbalances.

They can never be entirely eliminated.

When incorporating one machine into another structure –

like an aircraft engine – it’s important to understand the

machine’s vibration output to avoid consequences such

as exciting structural resonances.

Frequency Analysis

Frequency analysis is the most commonly used method

for analysing a vibration signal.

The most basic type of frequency analysis is the Fast

Fourier Transform (FFT) which is a digital algorithm for

performing,

1
() = ∫ () −2
0

It converts a signal from the time domain into the

frequency domain.

The product of this conversion is a power spectrum and

shows the energy contained in specific frequencies of the

overall signal.

This is quite useful for analysing stationary signals whose

frequency components do not change over time.

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