Physics and Chemistry Based Constitutive Framework for Thermo-Chemo-Mechanical Responses of Polymeric Materials
type: CreativeWork
description: This research has focused on understanding the mechanicPhysics and chemistry based constitutive framework for thermo-chemo-mechanical responses of polymeric materialsPhysics and Chemistry Based Constitutive Framework for Thermo-Chemo-Mechanical Responses of Polymeric Materialss and multi-physics of soft materials with rate-and temperature-dependent matrices. Such materials are oftentimes exposed to extreme environmental conditions such as Ultra-Violet (UV) light, elevated temperatures, and oxygen which degenerate their mechanical properties and contribute to their permanent failure. The irreversible changes in the mechanical response of polymers induced by such deleterious processes is commonly referred to as polymer aging. The ultimate goal of this work has been to identify the relevant damage processes affecting the lifetime of polymeric materials, and to develop predictive physics- and chemistry-based, thermodynamically consistent constitutive frameworks to evaluate their response under extreme environmental condition. A series of interconnected experimental, theoretical, and numerical studies were developed regarding the chemical, morphological, and mechanical changes that polymers and elastomers exhibit under thermo-photo-chemo-mechanical conditions. Emphasis was placed on linking the aggravation of macrostructural changes (such as cross-link breakage/formation and transformation of linkages) to the macromechanical response of aged polymers, and the development of a mathematically verifiable procedure for incorporating stored and dissipated energies – obtained through chemical experiments – into the thermodynamic formalism. Fracture was considered using the phase-field approach to brittle failure through development of robust and efficient numerical algorithms intended to solve the highly coupled and nonlinear displacement-damage problems. Results demonstrate that several chemical characterization tests such as equilibrium swelling, differential scanning calori…
abstract: This research has focused on understanding the mechanicPhysics and chemistry based constitutive framework for thermo-chemo-mechanical responses of polymeric materialsPhysics and Chemistry Based Constitutive Framework for Thermo-Chemo-Mechanical Responses of Polymeric Materialss and multi-physics of soft materials with rate-and temperature-dependent matrices. Such materials are oftentimes exposed to extreme environmental conditions such as Ultra-Violet (UV) light, elevated temperatures, and oxygen which degenerate their mechanical properties and contribute to their permanent failure. The irreversible changes in the mechanical response of polymers induced by such deleterious processes is commonly referred to as polymer aging. The ultimate goal of this work has been to identify the relevant damage processes affecting the lifetime of polymeric materials, and to develop predictive physics- and chemistry-based, thermodynamically consistent constitutive frameworks to evaluate their response under extreme environmental condition. A series of interconnected experimental, theoretical, and numerical studies were developed regarding the chemical, morphological, and mechanical changes that polymers and elastomers exhibit under thermo-photo-chemo-mechanical conditions. Emphasis was placed on linking the aggravation of macrostructural changes (such as cross-link breakage/formation and transformation of linkages) to the macromechanical response of aged polymers, and the development of a mathematically verifiable procedure for incorporating stored and dissipated energies – obtained through chemical experiments – into the thermodynamic formalism. Fracture was considered using the phase-field approach to brittle failure through development of robust and efficient numerical algorithms intended to solve the highly coupled and nonlinear displacement-damage problems. Results demonstrate that several chemical characterization tests such as equilibrium swelling, differential scanning calori…
author: Najmeddine, Aimane
language: en
keywords: polymer, photo-oxidaiton, thermo-oxidation, elastomer, phase-field, damage, multi-physics
license: http://rightsstatements.org/vocab/InC/1.0/
date published: 2023-01-12
date modified: 2026-07-22T22:18:49Z
provider: Virginia Tech
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Virginia Tech

PropertyValue
property ID: Handle
value: http://hdl.handle.net/10919/113158