Development of a fast numerical simulator for infrared thermography testing signals of delamination defect in a multilayered plate

In this paper, a very fast numerical solver for simulating signal perturbation of infrared thermography testing (IRT) due to delamination defects was developed by using the database of unflawed IRT information. First, the IRT signal simulation method of the frequency-domain summation scheme proposed by authors is briefly introduced as the bases of the present fast-forward solver. Second, a database-type fast numerical scheme for rapid simulation of single-frequency IRT harmonic signals was proposed to enhance the efficiency of the IRT simulation without worsening the numerical precision. In addition, in order to efficiently implement the proposed fast solver for simulation of delamination defects in a multilayered plate, a two-dimensional (2-D) shifting symmetry strategy was applied to reduce the computational burden for the construction of the unflawed database. Based on the proposed scheme, a fast-forward numerical code was developed for simulation of IRT signal perturbation due to the delamination defect. The validity of the proposed scheme and the corresponding numerical code was verified by comparing its results with those of a full FEM code and experiments. It was demonstrated that the database-type fast scheme can significantly reduce the simulation time for the IRT signal perturbation due to a delamination defect but keep the same simulation accuracy with that of the full FEM code.