Virtual Fields Method on Planar Tension Tests for Hyperelatic Materials Characterisation

New methods are emerging in the material characterisation field with the aim of exploiting innovative full-field strain measurement techniques. Besides experimental issues, also numerical procedures for inverse problems should adapt to a new philosophy: the large amount of data referred to local strains should be used in an appropriate way to obtain as much benefits as possible. In this context, an experimental and numerical procedure for the characterisation of hyperelastic materials is proposed. Planar tension tests have been performed on flat rubber specimens of different geometries. Strain maps obtained by means of a 2D Digital Image Correlation system are used to implement the virtual fields method, to estimate material dependent parameters of two of the most known hyperelastic constitutive laws: Ogden and 2nd order Mooney-Rivlin models. Numerical results and comparisons with experimental data are shown, analysing also aspects concerning implementation of the numerical procedures and computational efficiency of the algorithms.