This article presents a methodology for real-time monitoring of fatigue life in machinery components that utilizes the accumulation of entropy to assess the severity of degradation associated with fatigue. Using this concept, a prototype called the fatigue monitoring unit that automatically shuts down the machine prior to the onset of fatigue fracture based on a user-specified factor of safety is developed. The method is applicable to variable loading and does not require the specification of the loading history or loading sequence. The results of a series of laboratory fatigue tests pertaining to Al 6061-T6 and SS 304 specimens, which show the utility of the approach and its suitability for implementation in the field, are provided.
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