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A Numerical and Experimental Study of the Thermodynamically Consistent Nonlinear Viscoelastic Response of an Expoxy Polymer in the Glassy Regime

by Wang, FeI

Abstract (Summary)
The mechanical behavior of polymers in the glassy state is complex and several models have been developed to describe a variety of phenomena. A thermodynamically consistent nonlinear viscoelastic constitutive theory is considered to capture the wide range of behaviors observed in glassy polymers, including phenomena like yield, stress relaxation, nonlinear stress–strain behavior under complex loading histories and others. The Helmholtz free energy potential for an isotropic, thermorheologically simple, viscoelastic material is constructed, and quantities such as the stress and entropy are determined from the Helmholtz potential using Continuum Mechanics. The objective of the present study is to evaluate the thermomechanical response of an epoxy polymer with this constitutive theory focusing on the transition from the rubbery to the glassy regime and calculating all necessary parameters for the loading portion in the glassy regime. The nonlinear viscoelastic formulation is written in Matlab and correlated with experimental results.
Bibliographical Information:

Advisor:

School:University of Cincinnati

School Location:USA - Ohio

Source Type:Master's Thesis

Keywords:polymer viscoelasticity

ISBN:

Date of Publication:01/01/2006

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