ACTIVE THERMOGRAPHY TECHNIQUE FOR FATIGUE DAMAGE CHARACTERIZATION IN GEARS

Active Thermography (AT) is a Non Destructive Technique (NDT) that may be an efficient alternative to evaluate possible microstructural alterations inside materials due to damaging conditions. In this paper, a fatigue damage identification on two different gears (standard and thin-rim) was conducted by using an AT approach with a Lock-In technique. Both gears were previously tested under bending fatigue conditions, by loading the teeth at the so called Single Contact Point by a dedicated equipment. Damaged and undamaged zones were identified, phase maps and thermal diffusivities were estimated. In this way, a possible fatigue damage characterisation was pointed out by using the thermal diffusivity variation as damage parameter.