JavaScript is disabled for your browser. Some features of this site may not work without it.
A Multiscale Approach For Tailoring The Macro-Properties of Polycrystalline Materials

Author
Kouchmeshky, Babak
Abstract
The first half of this thesis provides a continuum approach for predicting the
constitutive response of HCP polycrystals using a simple non-hardening constitutive
model incorporating both slip and twinning. This has been achieved
by considering a physical based methodology for restricting the amount of the
twinning activity. A continuum approach is used in modeling the texture evolution
that eliminates the need for increasing the number of discrete crystal orientations
to account for new orientations created by twinning during deformation.
The polycrystal is represented by an orientation distribution function using the
Rodrigues parameterization. A total Lagrangian framework is used to model
the evolution of microstructure. Numerical examples are used to show the application
of the methodology for modeling deformation processes.
In the second half, the quantification and propagation of uncertainty in process
conditions and initial microstructure on the final product properties in a
deformation process is presented. The stochastic deformation problem is modeled
using a sparse grid collocation approach that allows the utilization of a deterministic
simulator to build interpolants of the main solution variables in the
stochastic support space. The ability of the method in estimating the statistics
of the macro-scale microstructure-sensitive properties and constructing the convex
hull of these properties is shown through examples featuring randomness in
initial texture and process parameters. A data-driven model reduction methodology
together with a maximum entropy approach are used for representing
randomness in initial texture in Rodrigues space. Comparisons are made with
the results obtained from the Monte-Carlo method.
Date Issued
2010-04-09Type
dissertation or thesis