Low-Coherence Speckle Interferometry (LCSI) for characterisation of adhesion in adhesive bonded joints

Low Coherence Speckle Interferometry (LCSI) combines the depth-resolved measurement of Low Coherence Interferometry (LCI) with the high-accuracy deformation measurement of Electronic Speckle Pattern Interferometry (ESPI). Depth-resolved deformation measurement enables the characterisation of the behaviour of interfaces in multi-layer materials or structures while changing the ambient conditions. In this paper LCSI is introduced as a new tool for characterisation of adhesion. The experimental set-up and the principle of work are described. A FEM-model of an adhesive bonded aluminium joint is developed to analyse the behaviour of the Al-adhesive interface during mechanical testing. Some recent results are shown. This application demand measurements on a microscopic scale (camera field of view down to 500 x 500mum).