Identification of Hyperelastic Constitutive Model for Rubber-Like Materials Based on Digital Image Correlation (Dic) and Model Updating

The mechanical behavior of rubber-like materials is usually characterized by a strain energy density function, w. The parameters defining the density function, w, are considered as material parameters that need to be identified. Traditional experimental techniques, such as strain gauges, require numerous tests in homogeneous deformation modes and cut-out standard samples, to determine the appropriate strain energy form and parameters. In the present paper, the Finite Element (FE)-model updating based techniques is used to reduce the number of experimental tests for the identification of rubbery materials. In order to identity the analytical form of the strain energy, w, it is possible that we use only one single test of the component containing the rubber-like material. The example of an engine mount is used to illustrate the methodology. Two-dimensional field of in-plane inhomogeneous strains on the surface of the rubber block is measured using a Digital Image Correlation (DIC) technique, which provides extensive amounts of experimental data in one single test, replacing traditional multiple tests with multidimensional loading paths. An optimization loop using the response surface method is applied to minimize the equilibrium gap to search for the parameters of the stain energy function.