? Please consider attending the following: MATERIALS ENGINEERING SEMINAR "3D Multi-Scale Crystal Plasticity Finite Element Modeling of Nano-Metallic Multilayers" By Zara Molaeinia Purdue MSE Ph.D. Preliminary Exam Advisor: Professor David F. Bahr ABSTRACT Nanometallic multilayers (NMMs) are two-dimensional nanosystems made of alternating metallic nanolayers as unique multifunctional materials with novel properties such as high strength and ductility. The essential concepts differentiating NMMs from their bulk counterparts are the primary role of the layer thickness and the detailed structure of interfaces as the controlling parameters to modify and regulate laminate composites multifunctionality. Design and behavioral prediction of NMMs necessitate an exhaustive study and a profound understanding of anisotropic plastic response in single and polycrystalline NMMs as well as strengthening mechanisms ascribed to layers and interfaces morphology and composition, crystallographic orientations demarcated by grain boundaries, precipitates, and dislocation mechanisms in different segments. Multiscale modeling of NMMs using 3D crystal plasticity in a nonlinear finite element (CPFE) framework is being developed to investigate the mechanical behavior of these nanolaminate systems. The model is governed by features at three dominant scales, viz. (i) sub-layer scale characterized by the morphology and size of the precipitates, (ii) layer scale of single crystals portrayed by layers and interfaces characteristics, and (iii) super-layer scale corresponding to representative polycrystalline aggregates. In the multiscale spectrum, the length scale variation is considered to stride from nano- to micro- and millimeter. Physics-based non-local crystal plasticity constitutive models are considered at different scales to capture dislocation mechanisms and size effects due to the presence of precipitates, interfaces and grain boundaries. In order to bridge the multiscale segments, methods of parametric homogenization are availed. Date: Thursday, December 20, 2018 Time: 9:00 A.M. Place: ARMS 1103