Temperature and Strain Rate Dependent Simulation of High Speed Tensile Tests of i-PP

M. Keuerleber, N. Woicke, S. R. Raisch, P. Eyerer

Institute for Polymer Testing and Polymer Science (IKP),
University of Stuttgart, Germany

Pfaffenwaldring 32, D-70569 Stuttgart, woicke@ikp.uni-stuttgart.de

Abstract

The aim of this study is to minimise the testing effort for material characterisation in the linear viscoelastic region. Results derived from Dynamic-Mechanical-Analysis (DMA) and bulk tests are combined and compared with the elasticity modulus (E) measured by tensile tests.

Using the thermorheologic simple theory a time-temperature shifted relaxation spectrum of isotactic polypropylene is generated from shear and bulk experiments. However, the time-temperature shift functions for the load cases have different curve progressions. The relaxation spectra are fitted with a modified generalised Maxwell model.

With this data, simulations of tensile tests are performed via finite-element-analysis (FEA) with the software MARC. For comparison, tensile tests at varying strain rates (10^-3 s^-1 to 10¹ s^-1) and temperatures (‑20°C to +40°C) are executed. Thus, the glass transition temperature of approximately 0°C /1/ is well within the experimental temperature range.