The framework of this study is to develop a methodology based on digital image
correlation (DIC) applied in biaxial straining under large deformations to calibrate
the rubber computational modeling by the finite element method (FEM). Since the
material approaches incompressibility, different shape functions were adopted to
describe the fields of pressure and displacements according to the finite element
hybrid formulation. Biaxial experiments were performed in a cruciform machine and
the applied methodology was validated through a classical bulge test. Despite the low
biaxiality degree, reasonable results were obtained to nominal strain levels higher
than 300%, with the proposed methodology. A new method for obtaining the
nominal stress-strain relationship was proposed using Abaqus software. The
validation was conducted by numerical simulations and biaxial extension
experiments.
Keywords
elastomers, hyperelastic models, biaxial extension, digital
image correlation
