Measurement of sonic pulse velocities on structural elements

The measurement of the sonic pulses velocities in a given material is commonly referred to as sonic test. These tests consist, mainly, on inducing a wave by impact with an instrumented hammer and registering the reception of the wave through an accelerometer. Knowing the wave travel distance (measured on-site) and the wave travel time (computed by the difference between the impact and the reception instants), the propagation velocity of the sonic wave is determined. This velocity is related to the higher or lower compactness of the material crossed by the wave, in particular, to its stiffness.
These tests allow, for example, estimating in a non-destructive way the higher or lower compactness of a material, i.e. to detect different materials, defects or voids in elements and to assess its uniformity.

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