Fatigue damage detection using a speckle-contrast technique

An optical setup based on speckle-contrast measurement is proposed as an alternative to analyze fatigue damage on surfaces of metal samples. Based on the dispersion of the light, generated by a laser beam reflected by the surface, roughness and fatigue damage are analyzed after a specially designed fatigue test of metallic samples. The experimental results are obtained from an aluminum alloy type A319 modified with strontium with nodular silicon precipitates that was subjected to a fatigue procedure based in the norm ASTM E647.