Separation of plastic deformations in polymers based on elements of general nonlinear theory

TL;DR

This paper introduces a nonlinear deformation theory-based method to distinguish plastic deformation in polymers, facilitating better thermodynamic modeling and measurement of stress relaxation.

Contribution

It presents a novel nonlinear geometric approach to separate plastic from total deformation in amorphous polymers, including a new stress relaxation parameter.

Findings

Separation of plastic deformation from total deformation tensor.

Introduction of a stress relaxation rate parameter.

Discussion of experimental configurations for measuring the parameter.

Abstract

We report a method for describing plasticity in a broad class of amorphous materials. The method is based on nonlinear (geometric) deformation theory allowing the separation of the plastic deformation from the general deformation tensor. This separation allows an adequate pattern of thermodynamical phenomena for plastic deformations in polymers to be constructed. A parameter describing the stress relaxation rate of the material is introduced within the frame of this approach. Additionally, several experimental configurations to measure this parameter are discussed.