LASER-GENERATED ULTRASOUND APPLIED TO 2-LAYERED MATERIALS CHARACTERIZATION - SEMIANALYTICAL MODEL AND EXPERIMENTAL VALIDATION

This paper presents a new and original model of laser ultrasonics, ada pted to structures made of two homogeneous and orthotropic layers (pai nted metals, composites, etc.). The cylindrical symmetry of the model allows fast calculation and observation of the displacements over a lo ng duration. The simulations are compared with the experimental result s performed with a Nd:Yag laser generation and a heterodyne interferom eter. Applied to NDT, this model is used to optimize the choice of a p aint covering a metallic plate in order to improve the detection of de fects such as the effects due to corrosion. (C) 1998 Elsevier Science B.V.