Abstract
This paper presents a method to identify the geometrical shape and the location of the debonding failure embedded in a concrete structure by processing nonstationary thermal images of the structural surface captured by an infrared thermography camera. In the proposed method, the structure is modeled as a homogeneous infinite plate whose boundary condition on the observed surface is known. The temperature field in the plate is represented by a truncated power series with respect to time, and a layer-by-layer inverse analysis scheme using a regularized interlayer transfer matrix based on 2D Fourier transform is carried out to obtain the sharper image of the failure as well as the depth of the damaged layer. The estimated depth is mapped as a depth image which displays the shape of the failure as well as their depth. The influence of the truncation order as well as the time interval of measurement is investigated by numerical simulations and experiments.
