Some new ideas in dynamic thermal tomography

Dynamic Thermal Tomography (DTI) is a new area of Thermal Non Destructive Techniques (TNDT), very attractive for in field detection of defects inside materials. lt is based on the energetic excitation of solids, resulting in the dynamic distribution of the temperature field on their surface. Defects, inside the solid, change the evolution and the distribution of the surface temperature field. Solving the inverse thermal problem, which involves the processing of surface temperature field, one gets information on the inner structure of solids. Tests has been performed on two specimens compound of 5 layers, with thickness 1.8 mm each. Air holes in internal layers, performed in different shapes and arrangements, simulate defects. Another defect was simulated by a lack of glue. The results for the surface temperature in correspondence of defects show a dependence with time close to that of the simulated curves. Synthesized images of different inner layers of the material show the presence of defects whose position and depth are in good accordance with those of the real one, as it has been verified after destroying the specimens at the end of the experiment.