This paper presents an innovative wing profile featuring an internal truss-like
structure of chiral topology. The chiral design is selected because of its unique
deformation characteristics, which produce a theoretical, in-plane Poisson’s ratio of
. Such
a Poisson’s ratio yields a very high shear modulus, which in principle does not require
the wing profile to be defined by a closed section or stressed-skin configuration. In
addition, the peculiar deformation mechanism of the chiral configuration allows large
decambering deflections to occur, with all the members of assembly behaving within
the linear range of the material. Hence the proposed design combines large
chordwise compliance and large in-plane shear stiffness. Such conflicting
mechanical properties can be achieved through the proper selection of a
limited number of geometric parameters defining the core configuration.
The objective of the paper is to investigate the compliance characteristics
of the airfoil. Two-dimensional profiles, designed according to results from
previous investigations, are manufactured and tested to assess compliance and
evaluate decambering deflection limits. The experimental analysis is guided by
numerical models that account for deviations from the ideal configuration due to
manufacturing limitations. Numerical and experimental results demonstrate the
influence of core geometry on the compliance and confirm the ability of
chiral-core airfoils to sustain large deflections while not exceeding yield strain
limits.
