Experimental method for rubber deformation analysis using in situ X-ray tomography and digital volume correlation with FEM validation

The grip and rolling resistance of car wheel tires on a road surface is strongly influenced by the mechanical properties of the rubber and especially by the deformation of this rubber during indentation by the road asperities. This paper presents the results of a simplified indentation experiment. A cylindrical block of rubber containing microstructural markers is indented by a sphere in situ inside an X-ray Computed Tomograph. The presence of markers intentionally added to the rubber gum allows us, after suitable image processing for contrast improvement, to measure with a very good precision the displacement field inside the rubber during the indentation using Digital Volume Correlation. The measured displacement is compared with the result of an axisymmetric finite element modeling calculation reproducing the experimental configuration. The close correlation between measured displacements and finite element modeling shows that the proposed method is suitable for studying rubber/road contact.