Non-linear ultrasound investigation of extended plates

Abstract: A non-linear ultrasound non-destructive testing method called Non-linear Wave Modulation Spectroscopy is studied. The method shows the non-linearity of the test specimen and can in that way detect cracks. It is at present non-localizing. For some particular objects like extended plates and long tubes, the whole object cannot be investigated in one sampling. It is for these objects important to know in which region the crack might be and one needs to know the wave field. In this report the wave field from an acoustic source in a plate is shown experimentally and numerically. Further, in order to obtain higher localisation to a small region the concept of a standing wave in a resonator can be studied.