A generalized mechanical model using stress-strain duality at large strain for amorphous polymers

TL;DR

This paper introduces a generalized 3D mechanical model for amorphous polymers at large strains, utilizing stress-strain duality and precise transport operators to improve prediction accuracy across complex load cases.

Contribution

It presents a novel large-strain 3D model with exact kinematics and stress-strain duality, enhancing simulation accuracy for amorphous polymers under combined loads.

Findings

Significantly improved simulation accuracy for tension, compression, and shear.

Better agreement with experimental results compared to classical models.

Model validated on polycarbonate showing robust performance.

Abstract

Numerous models have been developed in the literature to simulate the thermomechanical behavior of amorphous polymer at large strain. These models generally show a good agreement with experimental results when the material is submitted to uniaxial loadings (tension or compression) or in case of shear loadings. However, this agreement is highly degraded when they are used in the case of combined load cases. A generalization of these models to more complex loads is scarce. In particular, models that are identified in tension or compression often overestimate the response in shear. One difficulty lies in the fact that 3D models must aggregate different physical modeling, described with different kinematics. This requires the use of transport operators complex to manipulate. In this paper, we propose a mechanical model for large strains, generalized in 3D, and precisely introducing the adequate transport operators in order to obtain an exact kinematic. The stress strain duality is validated in the writing of the power of internal forces. This generalized model is applied in the case of a polycarbonate amorphous polymers. The simulation results in tension/compression and shear are compared with the classical modeling and experimental results from the literature. The results highly improve the numerical predictions of the mechanical response of amorphous polymers submitted to any load case.