Scaling of the Strain Hardening Modulus of Glassy Polymers with the Flow Stress

TL;DR

This paper demonstrates that the strain hardening modulus of glassy polymers scales linearly with flow stress across various conditions, aligning experimental data with simulation results and discussing underlying mechanisms.

Contribution

It provides evidence that the linear relationship between strain hardening modulus and flow stress holds in simulations, clarifying previous discrepancies and exploring temperature and strain rate effects.

Findings

Linear relation between G_r and flow stress confirmed in simulations.

The ratio of G_r to flow stress varies with temperature and strain rate.

Experimental and simulation data are consistent in showing this linear scaling.

Abstract

In a recent letter, Govaert et al. examined the relationship between strain hardening modulus $G_r$ and flow stress $\sigma_{flow}$ for five different glassy polymers. In each case, results for $G_r$ at different strain rates or different temperatures were linearly related to the flow stress. They suggested that this linear relation was inconsistent with simulations. Data from previous publications and new results are presented to show that simulations also yield a linear relation between modulus and flow stress. Possible explanations for the change in the ratio of modulus to flow stress with temperature and strain rate are discussed.