  In our analysis, we show that Baldelli and Bourdin's work is only valid when
describing the behaviour of a film bonded to an elastic pseudo-foundation,
where Poisson's ratios of both bodies are in between -1 and 0 or in between 0
and 0.5 (where both Poisson's ratios are sufficiently away from 0 and 0.5), and
with an asymptotic condition that is different to what the authors present. We
also show that, for all Poisson's ratios, the authors' phase diagram is
four-dimensional and not two-dimensional. Also, due to the Poisson's ratio
dependence, the asymptotic scalings that the authors present are insufficient
to derive their proposed models. Furthermore, the authors' scaling of the
displacement field implies that their method cannot be applicable to films (or
strings) with planar loading, unless the normal displacement is zero. Finally,
by deriving a Winkler foundation type solution for a plate supported by an
elastic pseudo-foundation via the method implied by the authors, we show that
the authors' method cannot be applied to plates due to the structure of the
overlying body (i.e. the limits of integration of the plate) and the foundation
(i.e. planar-stress free condition of the foundation), unless planar
displacement field is identically zero. Despite the limitations of the authors'
work, we highlight its strength by showing that unlike the classical derivation
of the Winkler foundation equation, Baldelli and Bourdin's approach does not
violate the volume conversation laws or violate the governing equations of
mathematical elasticity.
