Fatigue life assessment by means of full-field ESPI vibration measurements

Electronic Speckle Pattern Interferometry (ESPI) technology gives nowadays the opportunity to measure high spatially defined 3D displacements in a wide frequency range by means of optical laser techniques. An experiment-based procedure for fatigue behaviour assessment of mechanical components is proposed in this paper. ESPI technology is described in brief in order to explain how to measure full-field dynamic displacements. From the ESPI complex-valued displacement fields at each frequency line and constitutive laws, stress&strain fields are numerically derived to be directly processed, without the aid of any structural model, by an adopted cumulative damage model. Fatigue life assessment is thus obtained by means of an experiment-based procedure. The described approach is applied on a car brake disk and reported in detail.