  We present an experimental approach to discriminate models describing the
mechanical behavior of polymeric materials. A biaxial loading condition is
obtained in a multiaxial testing machine. An evaluation of the displacement
field obtained by digital image correlation allows us to evaluate the
heterogeneous strain field observed during these tests. We focus on the
particular case of hyper-elastic models to simulate the behavior of a
rubber-like material. Different expressions of hyper-elastic potential are used
to model experiments under uniaxial and biaxial loading conditions.
