Nondestructive inverse approach for determining thermal and geometrical properties of internal defects in CFRP composites by lock-in thermography

Resolution approach of an inverse problem by lock-in thermography was developed for research geometric and thermal properties of internal defects, which are found in composites (CFRP), as depth, size, thermal conductivity and heat capacity. We have developed a new hybrid algorithm that uses the adaptive simulated annealing algorithm and the generalized patterns search algorithm to calculate the depth, size, thermal conductivity and heat capacity of defects. The gaps between results and literature values are very small, they do not exceed 4%. For optimizing the inverse problem objective function, the proposed algorithm has converged faster than literature algorithms.