The paper starts with a review of constitutive equations for
rubber‐like materials, formulated in the invariants of the right
Cauchy—Green deformation tensor. A general framework for the derivation
of the stress tensor and the tangent moduli for invariant‐based
models, for both the reference and the current configuration, is presented.
The free energy of incompressible rubber‐like materials is extended to
a compressible formulation by adding the volumetric part of the free energy.
In order to overcome numerical problems encountered with
displacement‐based finite element formulations for nearly
incompressible materials, three‐dimensional finite elements, based on
a penalty‐type formulation, are proposed. They are characterized by
applying reduced integration to the volumetric parts of the tangent stiffness
matrix and the pressure‐related parts of the internal force vector
only. Moreover, hybrid finite elements are proposed. They are based on a
three‐field variational principle, characterized by treating the
displacements, the dilatation and the hydrostatic pressure as independent
variables. Subsequently, this formulation is reduced to a generalized
displacement formulation. In the numerical study these formulations are
evaluated. The results obtained are compared with numerical results available
in the literature. In addition, the proposed formulations are applied to 3D
finite element analysis of an automobile tyre. The computed results are
compared with experimental data.