Page 34 - Vibrations

() is the spectrum of the

impulse response of the

machine which will show up

any resonances which will be

vibrations sources.

Here is a photo of a wheel tapper using his hammer which

acts as in impulse response function.

As a white noise source it will stimulate all vibrations in

the wheel.

He knows what a perfect wheel sounds like. If there is a

fracture, () will change and he will be able to hear any

additional resonances.

Although the technique is very old, it is still used today to

determine the Transfer Function of a machine.

Today accelerometers are used to measure vibrations.

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