Acoustic Emissions and Thermography Monitoring In Fatigue Crack Propagation In Aluminum Samples: a comparative study

This paper aims to monitor the fatigue crack propagation by two different experimental techniques. Three acoustic sensors were placed on the sample in order to monitor the evolution of the acoustical events during the cyclic load application; at the same time the change in temperature was examined by thermography. Tests were carried on aluminum samples (Al 5068) previously cracked, by cutting notches having known sizes and geometry. Successively X-Ray diffractometry analysis were performed in order to establish the given initial stress state of each sample. Specimens were then subjected to mechanical fatigue tests. During these tests the crack propagation was continuously examined and recorded by both techniques. Data obtained, in terms of number of hits, amplitude signals and maps’ temperature, were compared in order to evaluate the capability of each technique in following the evolution of the damage process.