  We address the total Lagrangian finite element implementation of the
Flory-Rehner free-energy function in the framework of a hyperelastic material
model. We explicitly give all the equations required to implement this material
model in an implicit nonlinear finite element analysis, particularly, we show
how to derive the so-called algorithmic or consistent linearized tangent
modulus in the Lagrangian description. Some analytical and numerical results
for different boundary-value problems are presented to validate the
implementation.
