Phenomenological modelling of damage in polymer blends

To describe the constitutive behaviour of a certain class of polymer blends an elastoperfectly-viscoplastic and creep damageable material characterization is proposed. For a composite of 80 % Polystyrene and 20 % Ethylene Propylene Diene Monomer rubber (PSIEPDM) the specific parameters are determined from tensile tests in a particular range of strain velocities. To investigate the applicability of the model, the results of a finite element analysis for a laterally loaded thin plate (plane stress) with a circular hole are compared to measurements. Numerically calculated values are in reasonable agreement with reality; discrepancies can be ascribed to noise in experimental data. The finite element approach is evaluated with respect to the occurrence of mesh-dependence. Mesh-refinement shows convergence of solutions, attributable to the stabilizing influence of the viscous contribution in the constitutive equations