Nonlinear Schapery viscoelastic material model for thermoplastic polymers

Thomas Zink,Valerian Hirschberg,Manfred Wilhelm,Loredana Kehrer,Thomas Böhlke

doi:10.1002/app.52028

Thomas Zink, Valerian Hirschberg + Show 3 more

Open Access

https://doi.org/10.1002/app.52028

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Abstract

AbstractThe nonlinear mechanical behavior of viscoelastic materials is modeled based on the Schapery integral model containing internal variables. In this context, a new approach for the strain‐dependent material properties is introduced considering a one‐dimensional formulation with strain‐dependent nonlinear functions for an oscillatory load case. In addition to the viscoelastic storage and loss modulus, the higher order harmonic oscillations in the stress response are computed and compared to experimental data from Fourier transform rheology of Polyamide 6 (PA6). The comparison reveals a good agreement between the predictions of the nonlinear model and the experimental data for the higher harmonic intensity .

Highlights

The application of polymer-based material systems in the automotive and aircraft sectors has increased significantly in recent years due to their potential as low-weight materials, combining low weight with high specific stiffness and strength, their processability, and their relatively low cost
Thermosets and thermoplastics are often used as polymeric matrix
In terms of thermoplastic polymers, the solid material behavior is characterized by pronounced thermo-viscoelastic material properties.[2,3,4]

Summary

Introduction

The application of polymer-based material systems in the automotive and aircraft sectors has increased significantly in recent years due to their potential as low-weight materials, combining low weight with high specific stiffness and strength, their processability, and their relatively low cost. For linear viscoelastic material behavior, the time-dependent stress response σðtÞ to a uniaxial strain excitation εðtÞ An extension of the Boltzmann-superposition for nonlinear material behavior can be made using the Schapery model that has been developed for solid viscoelastic polymers.

Results

Conclusion