In some field of engineering (e.g. in the precision mechanics, medical instrumentation) elastic constructions are frequently applied using hyperelastic rubber-like materials which geometry is optimised by FEM software. To define the parameters of the material model applied in the FEM software it is necessary to use real experimental data getting from the uniaxial or/and biaxial strain tests of the rubber.
An equibiaxial measuring system using inflating method with image processing was developed for the characterization of hyperelastic rubber-like materials (in our case silicone rubber). The paper shows this optical measuring system and the result of the biaxial test of MED-4930 silicone rubber. We analysed the resulting error of the measuring system.
The benefit of this system constructed by our research group is that the measuring procedure can be automatized. By this visual monitoring method the test time could be significantly reduced. In addition the accuracy of the measurement could be increased due to curve fitted mathematically on the contour.