Acoustic resonance analysis, which also refers to sound testing, is a non-destructive testing method. It enables a fast and effective testing of a wide range of workpieces.
The physical effect is utilized, that a body which is stimulated suitably by an excitation, vibrates in certain characteristic frequencies, its natural frequencies. They are the “language” of the workpiece. Everything what has an influence on the mechanical strength (cracks) or on the material structure can be measured and evaluated by variances in the resonant spectrum.
With the acoustic resonant testing, you can detect cracks, nodularity, Perlite ratio, and weight variations. A range of compensation methods will help to filter the influences by temperature, aging, dimensional variance and others.
An example is shown in Fig 1 and Fig 2 RTE Akustik + Prüftechnik GmbH