A framework for analyzing hyper-viscoelastic polymers

TL;DR

This paper develops a predictive framework for the large strain rate response of hyper-viscoelastic polymers across various temperatures, using experimental data and fractional derivative modeling to extend understanding where direct testing is impractical.

Contribution

It introduces a novel framework combining DMA experiments and fractional derivative models to predict hyper-viscoelastic polymer behavior at high strain rates.

Findings

Constructed a master curve for storage modulus rate dependence.

Fitted a fractional derivative model to experimental data.

Derived stress-strain relationships at high strain rates.

Abstract

Hyper-viscoelastic polymers have multiple areas of application including aerospace, biomedicine, and automotive. Their mechanical responses are therefore extremely important to understand, particularly because they exhibit strong rate and temperature dependence, including a low temperature brittle transition. Relationships between the response at various strain rates and temperatures are investigated and a framework developed to predict large strain response at rates of c. 1000 s$^{-1}$ and above where experiments are unfeasible. A master curve of the storage modulus's rate dependence at a reference temperature is constructed using a DMA test of the polymer. A frequency sweep spanning two decades and a temperature range from pre-glass transition to pre-melt is used. A fractional derivative model is fitted to the experimental data, and this model's parameters are used to derive stress-strain relationships at a desired strain rate.