It is well-known that especially filled rubber-like materials exhibit under cyclic loading distinct stresssoftening phenomena commonly known as Mullins effect. Another important effect associated with the Mullins effect is that the material behaves anisotropic after having undergone large strain in a certain direction. These two effects can be explained by chain breakage and reconnection inside the material which is simulated in the present contribution by means of an innovative approach.
This approach allows us to transfer information from the micro level to the macro level and contrariwise. Therefore we define special finite element unit cells consisting of one tetrahedral element and six truss elements attached to each edge of the tetrahedron. Putting arbitrary configurations of such unit cells randomly together allows us to simulate complex structures of unfilled elastomers, e.g. rubber boots or seals.
Filler particles are added by replacing a certain part of the tetrahedrons by another type of tetrahedrons including linear-elastic material behaviour to represent the filler material. In this way we account for the increase of the stiffness and the strength of the composite material.
Based on comparisons with experimental results the breakage and reformation of polymer chains is simulated. We obtain a satisfactory correlation between the numerical results and the experimental data, especially for the large strain regime. A further main focus lies in the studies of the anisotropic effects in combination with the Mullins effect. Here we also arrange validations with experimental data in order to show the advantages of the proposed approach.