  We introduce a simplified model for the minimization of the elastic energy in
thin shells. This model is not obtained by an asymptotic analysis. The
thickness of the shell remains a parameter as in Reisner-Mindlin's model for
plates and Koiter's model for shells in the linear case. The simplified model
admits always minimizers by contrast with the original one. We show the
relevance of our approach by proving that the minimum of the simplified model
and the infimum of the full model have the same limit as the thickness tends to
0.
