Fatigue damage precursor detection and monitoring with laser scanning technique

Over the last decade, investigations into fatigue damage precursors have established that metal components subjected to cyclic stress develop surface-evident defects such as microcracks and slip bands [1-4]. These defects evolve with the development of fatigue. Detection of such damage precursors on a component and examination of their evolution can thus provide information on the state of the critical parts and prognostics of their catastrophic failure. Evolving surface defects, although of a different nature, can similarly be observed on some materials when subjected to thermal cycling fatigue.