  A reciprocal structure (RS) is a mechanical resistant structure formed by a
set of self-supporting elements satisfying certain conditions of structural
reciprocity (SR) . The first condition is that each element of the structure
has to support and be supported by the others. The second condition is that
these functions cannot occur in the same part of the element. These two
properties make beams and two-dimensional materials very much appropriate to
build RSs. Commonly seen in floors or roofs, SR is also present in art,
religious symbols and decorative objects. Da Vinci has drawn several examples
of such RSs. Here, we propose a simple nano version of a da Vinci's RS based on
graphene nanoribbons. The stability and resistance against mechanical impacts
(ballistic projectile) were investigated through fully atomistic molecular
dynamics (MD) simulations. We considered structures with three and four joins
with and without RS topologies. Our MD results showed that structures with RS
topologies are more impact resistant than those without SR, despite the fact
that the used graphene nanoribbons are highly pliable. We discuss these results
in terms of the number of joins, energy absorption and stress on the
structures. We discuss possible applications in nanoengineering.
