FEA-Based Design of Experiment for the Damping Determination of Thermoplastic-Rubber Compounds

In terms of recycling, polymer blends with rubber crumb filler material offer a high potential in adjusting both static and dynamic material properties. While the influence on stiffness and strength is considerably treated in literature, there are minor examinations on the damping of such compounds. Combining the properties of thermoplastics and elastomers, these materials tend to show a wide range of non-linear influences such as frequency, temperature and amplitude dependency. Especially the amplitude dependency is critical due to the transferability of the results between different stress states, loads and part geometries as well as the applicability in FEA simulations. In detail, the average strain energy per volume has been chosen as a physical measure for the amplitude dependency. This study provides extensive results of the influence of recycled rubber crumb filler on the stiffness and damping of Polyamide 6. A FE-based experimental design was developed to assure the comparability of the strain energy related dynamic properties. For the different testing conditions the average strain energy is not directly measurable and thus needs to be determined numerically. Cyclic tension and bending in a dynamic mechanical analyses, free decay of cantilever beams as well as modal analysis of plates have been analysed experimentally and numerically for validation. In addition, the boundary conditions have been varied to generate different stress states in the specimens. The results show perspectives and limits of the transferability of the results.