Digital Prognosis of Fatigue Residual Life of Lightweight Metallic Materials.

Fatigue damage of critical components and structures is an important phenomenon in engineering practice where service loads are normally much lower than the strength of materials. Few past studies focused on the correlation between macroscopic fatigue residual life and the micro-/meso-scale defect evolution He (Fatigue Fract. Eng. Mater. Struct. 36: 102-114, 2013), Shanyavskiy (AIP Conf. Proc. 2167: 020324, 2019), Tang (Int. J. Fatigue 70: 270 277, 2015). This study explores the fatigue damage with three significant contributions: (1) one of the first studies on predicting fatigue residual life at different load stages without prior knowledge of the load history, (2) a new multiscale fatigue damage index for linking of micro-/meso-scale defects and damage to macroscale high-cycle fatigue life, and (3) a novel incremental evaluation method for fatigue damage. A series of coordinated materials tests were conducted along with the corresponding numerical simulations. Experimental results indicate that our multiscale fatigue damage index (MFDI) is significantly better than the state of the art in terms of the correlation with actual fatigue life of test specimens and MFDI may serve as an ideal fatigue damage signature for nondestructive inspection of fatigue residual life. Our MFDI can also be potentially utilized to evaluate the impact of micro-/meso-scale defects and damage in new manufacturing processes of materials such as additive manufacturing and nanomaterials manufacturing. [ABSTRACT FROM AUTHOR]