The adhesive contact of a flat punch on a rubber-like substrate subject to a pull-out force or a bending moment. Part II: Experiments

Abstract

Indentation of rubber materials, like gels, tissues, polymers and other soft and incompressible materials is of great importance. These materials show large elastic strains when subjected to relatively fast loading (excluding viscoelastic phenomena). The present work focuses on the adhesive contact of such materials and is based on the analytical work of Part I. Flat punches of circular imprint are used and are subjected to pullout normal forces or to bending moments. Experiments are conducted with an artificial material (gel, reinforced with talc powder) that is modeled as a hyperelastic material. Such behavior can be modeled by using the well-known Mooney–Rivlin (M–R) strain energy density function. It is concluded that the indentation can be used to estimate the initial elastic modulus, but not both the material constants required by the (M–R) model. The present work is expected to extend indentation testing to important technologies like medical applications (health monitoring of tissues) and food industries (quality control of various production stages).