Anisotropic Damage Phenomena in Filled Elastomers: Experimental Observation and Constitutive Modeling

Most important macroscopic inelastic phenomena of filled elastomers are due to microscopic damage processes inside the rubber network. For example, the Mullins effect can be explained by debonding of polymer chains from the carbon black aggregates. In turn, the damage and following recovery of aggregates are responsible for the hysteresis. All these effects also induce anisotropy of an initially isotropic material. In the present contribution, we show how these effects can be quantified experimentally and simulated by a micro-mechanical model. The model is based on the decomposition of the rubber matrix into a purely elastic polymer, a polymer-filler and a filler cell network. The polymer-filler network model takes into account the debonding of polymer chains from filler aggregates and is thus able to predict the strain induced damage and the permanent set. The filler cell network model describes breakage and recovery of filler aggregates and is responsible for the hysteresis. The presented model is in accord with a broad range of experimental observations.