Shells and plates have been widely studied by engineers during the last
fifty years. As a matter of fact an important number of papers have been
based on analytical calculations. More recently numerical simulations
have been extensively used. for instance for large displacement
analysis. for shape optimization or even -in linear analysis -for
composite material understanding. But all these works lie on a choice of
a finite element scheme which contains usually three kinds of
approximations: 1. a plate or shell mndel including smnll parameters
associated to the thickness, 2. an approximntion of the geometry (the
medium sUrface of a shell and its boundary), 3. afinite element scheme
in order to solve the mndel chosen. VI Obviously the conclusions that we
can draw are very much depending on the quality of the three previous
choices. For instance composite laminated plates with damage like a
delamination is still an open problem even if interesting papers have
already been published and based on numerical simulation using existing
fmite element and even plate models. - In our opinion the understanding
of plate modelling is still an area of interest. Furthermore the links
between the various models have to be handled with care. The certainly
best understood model is the Kirchhoff-Love model which was completely
justified by P. O. Ciarlet and Ph. Destuynder in linear analysis using
asymptotic method. But the conclusion is not so clear as far as large
displacements are to be taken into account.