Study of micro-crack localization based on vibro-acoustic modulation

Abstract

As a prevalent nonlinear acoustic method, vibro-acoustic modulation (VAM) is more sensitive to micro-crack than the traditional linear acoustic. Nevertheless, recent theoretical and experimental studies have demonstrated that VAM cannot quantitatively ascertain the location of micro-crack. To overcome this limitation, VAM is combined with time reversal (TR) in this paper. The finite element (FE) software was used to simulate the process of VAM detecting micro-crack and the VAM experimental system was established by using an aluminum plate with presupposed micro-crack. The TR method was used to reverse the first-order nonlinear signals from VAM simulated signals in time domain, then the pre-processed signals were reloaded into aluminum plate model and the TR simulation was implemented. The results showed that the first-order side-lobe signals were able to focus around original crack location. It is proved that TR method can be used to combine with VAM and realize micro-crack localization.