-Hei, prøv å coin-tappe...
The “original” coin tapping method
is a manual test where the operator is tapping over the surface
of the object with a big coin, or a small hammer, as shown inFigure3.
1
. This is one of the oldest
and, in principle, simplest non-destructive tests. The operator listens to the resulting sound to find alterations, and hence indications of defects in the underlying material
[6]. When tapping over defective regions, with e.g. poorbonding quality, the sound will have more “hollow” characteristics than for the intact areas[3.In the same way,internal cracks will also change the sound response from the object.
http://www.ffi.no/no/Rapporter/12-00928.pdfDu vil høre en tydelig klangendring hvis, det er struktur skade....