Fatigue Analysis by Acoustic Emission and Thermographic Techniques

Aim of this paper is to evaluate how two non-destructive testing techniques may be integrated in a methodology to analyze the fatigue on materials. The compared techniques are the acoustic emission and the thermography. Both the techniques are able to reveal the strain energy even if was produced by strictly localized phenomena, as in the fatigue process. Moreover, both the techniques use the energy directly produced by the stressed body without any external source, differently from other NDT (US, X-Rays …). The experimental tests were carried out on flat steel specimens either under static loading or under sequences of increasing cyclic loading (R=0). The results allow to define the fatigue limit either by the thermography or by the acoustic emission. The present work is a first approach performed by the authors to compare and integrate the results obtained by experimental tests where the two methods were simultaneously applied.