Qualitative analysis of a 2D multiphysics model for vibration induced heating at closed defects

Vibrothermography is a promising Non-Destructive Testing (NDT) technique for the detection and characterization of closed defects. The technique uses elastic waves to excite the damaged component in order to generate frictional behavior at the internal closed defects. This results in vibrational energy dissipation through thermal diffusion. Apart from incipient damage detection, defect characterization is equally important, e.g. to anticipate the future defect growth. A proper characterization study necessitates a theoretical framework for in-depth analysis of the obtained thermal images. In the present work, we propose a 2D finite element multiphysics model for vibrothermography. The model consists of a mechanics/dynamics module to describe elastic wave propagation in samples with rough surface cracks, and accounts for nonlinear wave generation due to dynamic stimulation of the defect faces. In addition, the model is capable of calculating the energy dissipated due to frictional effects and translates it to a local generation of heat in the defect area. We will perform a qualitative analysis of the developed model by comparing the obtained numerical results with theoretical results already described in literature.