An Analysis of Non-Uniform Stress States in Finite Thin Film/substrate System: The Need of Full-Field Curvature Measurements
Ngo, Duc Minh
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/83939
Description
Title
An Analysis of Non-Uniform Stress States in Finite Thin Film/substrate System: The Need of Full-Field Curvature Measurements
Author(s)
Ngo, Duc Minh
Issue Date
2009
Doctoral Committee Chair(s)
Huang, Yonggang
Department of Study
Mechanical Engineering
Discipline
Mechanical Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Engineering, Mechanical
Language
eng
Abstract
"Current methodologies used for the inference of thin film stresses through curvatures are strictly restricted to stress and curvature states which are assumed to remain uniform over the entire film/substrate system. In this dissertation, we extend these methodologies to non-uniform stress and curvature states for the single layer of thin film or multi-layer thin film with non-uniform thickness subjected to non-uniform isotropic misfit strain between film and substrate. We obtain the film stresses and system curvatures in terms of the misfit strains and thickness in thin films. We derive the film stresses and interface shear stresses in terms of system curvatures and film thicknesses. They all feature a ""non-local"" dependence on curvatures, which make full-field measurement a necessity for the experimental inference of such stresses. We also extend the methodologies to the case that of single thin film/substrate subjected to non-uniform anisotropic misfit strain. The film stresses and system curvatures are both obtained in terms of the non-uniform, anisotropic misfit strains. For arbitrarily non-uniform, anisotropic misfit strains, it is shown that a direct relation between film stresses and system curvatures cannot be established. However, such a relation exists for uniform or linear anisotropic misfit strains, or for the average film stresses and average system curvatures when the anisotropic misfit strains are arbitrarily non-uniform."
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
