Fast simulation approach dedicated to infrared thermographic inspection of delaminated planar pieces

Abstract

In the present work, we propose a semi-analytical model based on the so-called truncated region eigenfunction expansion method, for the simulation of thermographic inspection. The problem is solved in the Laplace domain with respect to time, and the temperature distribution is approximated by its expansion on a tensor product basis. Configurations addressed by this model are stratified planar pieces affected by thin delamination flaws. Considered sources are lamps providing a thermal excitation at the surface of the inspected piece. The description of the delamination defects as thin air gaps between the piece layers proves to be equivalent with the introduction of a surface resistance to the heat flow, thus allowing their treatment via the applied modal approach without additional discretisation.