Constitutive Generalization of a Microstructure-Based Model for Filled Elastomers

A microstructure-based model of rubber reinforcement is presented describing filler-induced stress softening and hysteresis by the breakdown and re-aggregation of strained filler clusters. An extension of the previously introduced dynamic flocculation model, it considers incomplete deformation cycles that occur in the simulation of arbitrary deformation histories. For these inner cycles additional elastic stress contributions of clusters are taken into account. A constitutive generalization of the model is introduced by referring to the engineering concept of representative directions. This allows for an implementation of the model into FE codes. Fair agreement between measurement and simulation is obtained for CB-filled EPDM, loaded along various deformation histories.