Graduate Thesis Or Dissertation
 

Microcontinuum theory and orientational effects in smectic liquid crystals

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/ft848v30r

Descriptions

Attribute NameValues
Creator
Abstract
  • Micropolar Theory, a specialization of the Microcontinuum Theory advanced by A. C. Eringen in the early 1960ts has been used successfully in predicting the behavior of materials whose inner structure is composed of rod-like elements. Liquid crystals fall into this class of materials and their wide-spread use in Industry and in medical diagnostic devices requires a detailed analysis of their response to various external stimuli. To this end we have undertaken a detailed study of smectic liquid crystals using the micropolar theory. The first step was to develop a mathematical foundation for irreversible and nonlinear thermodynamics of liquid crystals and mathematical methods for obtaining thermodynamical restrictions on the material response coefficients of smectic liquid crystals. Full symmetry properties of liquid crystals have been employed in order to simplify the constitutive equations. This theory has then been applied to the physical problem of predicting orientational effects in smectic liquid crystals due to boundary influences, superposed shear flows, and thermal gradients. Since most experiments are carried out for viscometric flows we have considered the flow of smectic liquid crystals between two rotating coaxial cylinders. The velocity field obtained is found to include the classical Couette flow as a special case. We then compare our results with experiments and identify the material coefficients of the theory with physically measurable quantities such as apparent viscosity. The shear-rate dependence of viscosity at various temperatures of the srnectic range is determined and comparisons with experimental results yield good agreement. Finally, with the aim of constructing a viscoelastic theory suitable for description of materials with stretchable rod-like elements we first develop the theory of micropolar elasticity with stretch which takes into account the uniform stretching of the material's microelements. Future work involving the construction of the theory of micropolar viscoelasticity with stretch and its application to the study of viscoelastic waves is indicated.
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Publisher
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome) using ScandAll PRO 1.8.1 on a Fi-6670 in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces

Relationships

Parents:

This work has no parents.

In Collection:

Items

Thumbnail Title Date Uploaded Visibility Actions
file details KelleyThomasE1978.pdf 2017-10-20 Public Download