Nondestructive testing of the delaminated interface between two materials (Q2835611)

The article deals with the problem of detecting whether two materials that should be in contact are separated or delaminated. The goal is to find an acoustic technique to detect the delamination. The delamination is modeled as a thin opening between two materials of different acoustic properties. Asymptotic techniques are used to derive an asymptotic model where the delamination region is replaced by jump conditions on the acoustic field and flux. The asymptotic model has potential singularities due to the edges of the delaminated regions. It is shown that the forward problem is well-posed for a large class of possible delaminations. A special linear sampling method (LSM) is designed for detecting the shape of the delamination assuming that the background or undamaged state is known. Numerical experiments demonstrate that the LSM can indeed determine the shape of delaminated regions.