Influence of permanent deformation on the fitting quality and the simulation prediction of filled elastomers

Abstract

This work deals with the consequence of fitting hyperelastic material models to quasi-static multi-hysteresis test data with and without the correction of permanent deformation. Multi-hysteresis experiments are performed in different deformation states with equivalent amplitudes and equivalent strain rates. The investigations are performed on a carbon black filled ethylene propylene diene terpolymer rubber (EPDM). A second order polynomial hyperelastic material model was used to investigate the effect of elimination of permanent deformation during the fitting process. We find that the elimination of permanent deformation leads to a prediction of a stiffer material behavior. The validation of the obtained fitting parameters in the double-sided shear and uniaxial tension–compression loadings clearly shows that the elimination of the permanent deformation has a huge influence on the predicted stress field and strain field.