Data-Driven Correlation Analysis Between Observed 3D Fatigue-Crack Path and Computed Fields from High-Fidelity, Crystal-Plasticity, Finite-Element Simulations

Abstract

A systematic correlation analysis is performed between simulated micromechanical fields in an uncracked polycrystal and the known path of an eventual fatigue-crack surface based on experimental observation. A concurrent multi-scale finite-element simulation of cyclic loading is performed using a high-fidelity representation of grain structure obtained from near-field high-energy X-ray diffraction microscopy measurements. An algorithm is developed to parameterize and systematically correlate the 3D micromechanical fields from simulation with the 3D fatigue-failure surface from experiment. As a comparison, correlation coefficients are computed between the micromechanical fields and arbitrary planes through the microstructure. Correlation of the fields with arbitrary planes is found to be consistently weaker than correlation with the known crack surface, suggesting that the micromechanical fields of the cyclically loaded, uncracked microstructure might provide some degree of predictiveness for microstructurally small fatigue-crack path, although more work must be done to test this. In general, gradients of the field variables exhibit stronger correlations with crack path than the field variables, themselves. Results from the data-driven approach implemented here can be leveraged in future model development for the prediction of fatigue-failure surfaces