  In this paper, the numerical approximation of isometric deformations of thin
elastic shells is discussed. To this end, for a thin shell represented by a
parametrized surface, it is shown how to transform the stored elastic energy
for an isometric deformation such that the highest order term is quadratic. For
this reformulated model, existence of optimal isometric deformations is shown.
A finite element approximation is obtained using the Discrete Kirchhoff
Triangle (DKT) approach and the convergence of discrete minimizers to a
continuous minimizer is demonstrated. In that respect, this paper generalizes
the results by Bartels for the approximation of bending isometries of plates. A
Newton scheme is derived to numerically simulate large bending isometries of
shells. The proven convergence properties are experimentally verified and
characteristics of isometric deformations are discussed.
