Modeling the Influence of Material Structure on Deformation Induced Surface Roughening in AA7050 Thick Plate

A methodology for incorporating a description of material structure into a finite element formulation is presented. This work describes an experiment/simulation - based methodology for characterizing attributes of material structure, and then incorporating those attributes into a modeling framework. The modeling framework was used to study the development of deformation induced surface roughening in thin sheets machined from AA 7050 thick plate. Predicting this roughening phenomenon necessitates the quantification and representation of material structure and processes that exist over several size scales. Electron backscatter diffraction experiments were used for material structure characterization, which included crystallographic texture, distributions in grain sizes, and a distribution in intragrain misorientation. These distributions in structure were incorporated in digital microstructures which represented virtual specimens composed of finite element-discretized crystals. A continuum slip-polycrystal plasticity model was coupled with the digital microstructures to study the differences in roughening seen in specimens deformed along the rolling direction and transverse direction of the plate material. The success of these simulations build additional insight into how to incorporate material structure into deformation simulations, and build representative virtual specimens that can be used to study the complicated processes that underlie deformation mechanics in polycrystalline materials.