The hexachiral prismatic wingbox concept

Abstract

In this work the concept of using a chiral honeycomb as the internal structure for a passively morphing wing is explored. The use of a chiral honeycomb, which features an in‐plane negative Poisson's ratio, potentially offers high deformability whilst maintaining structural integrity of the wing box. A finite element simulation was carried out, coupling a complete two‐dimensional model of the wing and internal structure to a panel code flow solver. An iterative process was then used in order to predict the wing camber change with respect to airflow. The concept was validated experimentally through the construction of a prototype wing for wind‐tunnel testing. The measured response was non‐linear with respect to aerodynamic loading, but the final deflected shape at the design case compared well with the finite element prediction. The concept was proven to work for small camber changes, with larger deflections predicted by tailoring the mechanical properties of the hexachiral core. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Composite chiral structures for morphing airfoils: Numerical analyses and development of a manufacturing process

“…Such capabilities are numerically demonstrated in [9], and have been confirmed through a set of experiments performed on an airfoil prototype made of aluminum alloy [8]. A chiral wingbox with a polyamide chiral honeycomb core has been produced and benchmarked in [10] and dynamic properties of chiral truss-core assemblies have also been investigated [11]. The material selection for the analyses reported in [8,9] was not expected to provide optimal performance, but rather, it was driven by manufacturing constraints.…”

In-plane elasticity of a novel auxetic honeycomb design

“…NPR honeycomb structures feature synclastic curvature behavior, therefore making possible to provide dome-shaped surfaces when loaded with out-of-plane bending deformation [30,32]. Auxetic honeycombs have been employed to prototype radomes [33], adaptive and deployable structures [34], and morphing wings [35][36][37].…”

Tensile properties of shape memory alloy chiral honeycombs

“…Wojciechowski ( [13,14]) introduced first the concept of auxetics and chirality in molecular assemblies, while Prall and Lakes [15] demonstrated for the first time the possible use of chirality in structural bearing honeycomb configurations. The chiral honeycomb concept has been then explored for in-plane [16] an out-of-plane loading applications, ranging from honeycomb flatwise compression ( [17,18]) to aeroelastically tailored wingbox for morphing wings ( [19][20][21]). More recently, initial assessments of the deployability characteristics of a chiral SMA honeycomb antenna have been performed by the Authors [22].…”