Investigation of reconstructed three-dimensional active infrared thermography of buried defects: multiphysics finite elements modelling investigation with initial experimental validation

In this paper, we use a Multiphysics approach in COMSOL™ Platform to develop and validate a finite element model that simulates thermal images obtained in active thermography mode. This approach allows variation in material properties, the selection of active thermography methods such as Flash, Pulse Phase & Lock-in techniques, source wavelength, depth and dimensions of defect. We then take experimental thermography images of a defect embedded into a PLA block to compare with simulated images generated by the Multiphysics model. Our work shows the feasibility of real-time three-dimensional (3D) active infrared thermography (IRT) of buried defects. Such imaging can be hugely beneficial not only in quality control and process optimisation in additive manufacturing but also determination of shape and outline of tumours and plaques in medical applications.