An indentation technique is one of effective methods to determine the elastic modulus of materials using information about contact geometry, indenter shape and applied load. This paper presents a device and a method that allow us to estimate elastic modulus of soft materials through indentation by video tactile pneumatic sensor. The device is a sealed metal cylinder ending with a soft silicone shell of a semispherical shape with 5 mm radius. During penetration by the silicone tip into investigated material the measured parameters are contact radius and displacement of the central point of the shell.
The contact interaction between hollow elastic semisphere and a sample is modeled using finite element method. The axisymmetric contact problem was solved in geometrically nonlinear formulation, as the large strains were observed in the tests. The linear elastic model was used to describe mechanical properties of the sensor head and the sample. The Young’s modulus of the soft tissue was estimated based on the experimental results and numerical calculations.