CHARACTERIZATION OF DEFORMATION HETEROGENEITY DURING CYCLIC LOADING OF POLYCRYSTALLINE MATERIALS USING CRYSTAL PLASTICITY
Carson, Robert Allen
Cyclic loading of polycrystalline metals result in complex states of intragrain heterogeneous deformation. In cyclic loading, persistent slip bands (PSBs) have been studied since the late 1950s as a mechanism for void and crack formation in fatigued single crystals. Several models exist that offer an explanation for the formation of persistent slip bands. Of these, only a few potentially extend to polycrystalline aggregates, where the manner in which PSBs manifest is unclear. From these models, however, a recurrent ingredient is the presence of localized slip. In this work, we explore the necessary tools to characterize the localized slip and other deformation heterogeneities within a polycrystalline material using crystal plasticity models. First, we examine how to characterize heterogeneous intragrain deformation using kinematic and diffraction metrics. Next, we present a smooth crystal lattice orientation assumption imposed upon each crystal in order to allow for networks of slip to form and cross grain boundaries. Finally, we go over necessary frameworks to characterize the formation of slip networks across the sample.
Supplemental file(s) description: Readme file describing files contained in the zipped folder, Folder containing videos of the different slip network evolution
Crystal Plasticity; Dislocations; Finite Elements; Fatigue; Mechanical engineering
Miller, Matthew Peter
Dawson, Paul Richard; Warner, Derek H.
Ph. D., Mechanical Engineering
Doctor of Philosophy
dissertation or thesis