  In this paper we present a three-dimensional discrete model governing the
deformation of a viral capsid, modelled as a regular icosahedron and subjected
not to cross a given flat rigid surface on which it initially lies in
correspondence of one vertex only. First, we set up the model in the form of a
set of variational inequalities posed over a non-empty, closed and convex
subset of a suitable space. Secondly, we show the existence and uniqueness of
the solution for the proposed model. Finally, we numerically test this model
and we observe that the outputs of the numerical experiments comply with
physics.
