Conduction thermography for non-destructive assessment of fatigue cracks in metallic materials

Metallic materials are widely used in many applications of mechanical and aerospace engineering. Due to severe environmental and loading conditions, components and structures can experience cracking phenomena. In this regard, different non-destructive techniques were developed in the last years to detect and monitor cracks that can propagate during the actual loading conditions. This work deals with the application of the conduction thermography as a non-destructive technique for the offline control and inspection of different notched metallic specimens characterized by short fatigue cracks. The potentials of the technique have been demonstrated considering a low-cost set-up consisting of a power supply of low current and limited voltage, and a microbolometer sensor. Moreover, to further simplify the inspection, the specimens were not black coated. Quantitative results, in terms of crack lengths, have been obtained using a new procedure of data analysis and then compared to those provided by thermoelastic stress analysis, a well-established technique adopted for the detection and monitoring of cracks.