Mixed mechanical-metrological approach to quantify the fractographic damage in mechanical components subjected to cyclic loading

Abstract

The purpose of this paper is to present a mixed mechanical-metrological procedure, based on a fractographical approach, capable of correlating the fracture deformation behaviour with the fatigue loading history. The degradation mechanisms, which are related to the degree of fatigue damage, are identified from the changes in the dynamic response of the mechanical system. These changes, recorded during the tests by means of uniaxial acceleration sensors, are compared to different surface texture parameters, namely height parameters and material/void parameters, determined for both parts of the fracture surfaces after fatigue damage, and with the force needed for complete failure. The results show a direct relationship between the degree of fatigue damage, accounted for by the changes in the uniaxial acceleration sensors, and the surface texture parameters. This connection between the mechanical system dynamics and the surface metrology can provide a more precise fitness-for-service assessment.