Acquisition of kinematic surface fields for the assessment of 3D crystal plasticity numerical simulations

Guillaume Protin [webpage]

Research Engineer @ENSAM/PIMM

November 14, at 13h30 in Amphi A

ABSTRACT

The macroscopic behavior of materials is rooted in their microscopic structures. 

For polycrystalline materials, crystal plasticity models are capable of simulating the mechanical response of large polycrystalline aggregates while maintaining a resolution that allows for intra-granular observation. These models thus enable the study of the effects of microscopic mechanisms on macroscopic behavior. However, their validation must necessarily be carried out through a comparison of experimental and numerical results at the intra-granular scale, for which experimental acquisition is complex.

This presentation will outline a methodology for validating crystal plasticity models by comparing experimental and numerical surface strain fields during tensile tests (0-3.5% strain) on near-pure iron and Inconel 718. Experimental strain fields are obtained through Digital Image Correlation (DIC) acquired by Scanning Electron Microscopy (SEM) (displacement resolution of approximately 1.5 nm, field of view of 400 x 400 μm² , over 100 grains), along with crystallographic information obtained through Electron Backscatter Diffraction (EBSD). The comparison highlights the ability of the models to produce a satisfactory statistical distribution. However, the grain-by-grain analysis reveals the complexity of obtaining accurate local responses.

This work serves as an example demonstrating the value of coupling electron microscopy and digital image correlation for the quantitative analysis of complex mechanisms at micro- to nanometer scales.