Supportable Sandwich Control Surfaces

"Sandwich structural designs are the most weight efficient concepts for stability-critical components such as control surfaces. The objective of this proposal is to demonstrate the feasibility of producing honeycomb sandwich structure using a unique DoubleWalled Honeycomb design. This new ARDL honeycomb design is called Hexagonal Double walled structure or "HexD" This is depicted in Figure 1.HexD honeycomb core exhibits a unique cell structure. This design promises a higher stiffness to weight ratio, barrier resistance, and higher impact resistance. Higher stiffness has already been demonstrated using finite element analysis and prototypetesting. Figure 2 illustrates the significance of the using HexD over a common regular honeycomb in almost all the aspects of its usage as a control surface.The primary function of the face sheets is to provide the required bending and in-plane shear stiffness, and to carry the axial, bending, and in-plane shear loading. The primary function of the core is to stabilize the facings and carry most of the shearloads through the thickness. In order to perform this function the core must be as rigid and as light as possible. HexD performs these functions in a rather unique manner by having 86% more bond lengths and twice the walls.The primary structural role of the adhesive, which is the face/core interface in sandwich construction, is to transfer shear stresses between faces and core. This condition stabi