Debonding imaging of the aluminium/rigid polyurethane foam composite plates using A0 mode Lamb waves

Abstract

ABSTRACT Debonding regions can occur at the interface of aluminium/rigid polyurethane foam composite plates (ARCP) during manufacturing. To help improve the technological process of manufacture, it is essential to precisely locate these debonding regions. This paper proposed a method to image the debonding regions in the ARCP based on the A0 mode Lamb waves. To study the influence of overlap between the debonding region and the coil of the electromagnetic acoustic transducer (EMAT) on Lamb wave propagation, a three-dimensional finite element simulation model was developed. A positive linear relationship was obtained between the amplitude of the A0 mode and the overlap rate between the debonding region and the coil of the EMAT, which was verified through experiments. Based on such relationship, an imaging method was proposed. The imaging method consisted a horizontal scanning for the entire sample and vertical scanning for possible debonding regions determined from the horizontal scanning. The result of the imaging experiments can precisely reveal the size and position of the debonding regions, the maximum relative error of the centre position of the defect is 7.5% and the maximum relative deviation of the dimensions is 16.0%. This imaging method can serve as a reference for debonding imaging in composite plates.