Honeycomb Structures

For years, the aerospace and defense industries have utilized honeycomb products for their low weight and high-strength properties. In recent years, engineers involved in the automotive, marine and construction fields have shown interest in using honeycomb sandwich-structures as well.

A number of metallic and non-metallic materials are used to produce these honeycomb structures. Since most metallic honeycomb structures are made of aluminum, they are prone to corrosive damage caused by trapped moisture. The materials used to make non-metallic honeycomb structures include fiberglass, graphite, thermoplastics, Nomex (a non-flammable, aramid fiber paper), Kevlar (an aramid fiber) and several other specialty materials. These non-metallic resources can be very high in cost and may not meet the engineering specifications required by the particular application.

ARDLs Hex-D/T Honeycomb Superstructure

ARDLs Hex-D/T structural reinforcement design enables the properties of a celled, honeycomb structure to be enhanced. This is made possible by an inner and outer, double-walled cell that behaves in a way such that the inner cell reinforces the outer cell and vice versa. These cells are located on a base honeycomb sandwich panel in a hexagonal manner, structurally maximizing the design. (U.S. Patent 7,208,063)

The technology has broad potential for future aircraft applications. The Air Force is considering supersonic vehicles that have unique structural requirements. Aerodynamic performance constraints drive the design of these vehicles toward longer, sleeker configurations with thin fuselages, wings and tails (i.e. Concord and SR-7l). The design of future high-speed aircraft will continue to be driven by the desire to significantly reduce the structural weight of the aircraft while maintaining or increasing structural strength and stiffness.

ARDLs Hex-D/T honeycomb superstructure technology exhibits double the structural stiffness of conventional cores at the same core weight. This allows for thinner, lower weight, structural designs.

Unstabilized Core, Normalized Data Comparison

Property Hex-T (ARDL, Inc.) HRP % ChangeDensity (Pcf) 12.7 4.5 282% IncreaseBare Compressive Strength (psi) 289.0 113.0 256% IncreasePlate Shear (psi) 80.0 74.0 108% IncreaseImpact (psi) 158.0 117.0 135% Increase

Rubber. Plastic. Latex.

Hex-D/T Honeycomb Superstructure U.S. Patent 7,208,063Honeycomb Structures

For years, the aerospace and defense industries have utilized honeycomb products for their low weight and high-strength properties. In recent years, engineers involved in the automotive, marine and construction fields have shown interest in using honeycomb sandwich-structures as well.

A number of metallic and non-metallic materials are used to produce these honeycomb structures. Since most metallic honeycomb structures are made of aluminum, they are prone to corrosive damage caused by trapped moisture. The materials used to make non-metallic honeycomb structures include fiberglass, graphite, thermoplastics, Nomex (a non-flammable, aramid fiber paper), Kevlar (an aramid fiber) and several other specialty materials. These non-metallic resources can be very high in cost and may not meet the engineering specifications required by the particular application.

ARDLs Hex-D/T Honeycomb Superstructure

ARDLs Hex-D/T structural reinforcement design enables the properties of a celled, honeycomb structure to be enhanced. This is made possible by an inner and outer, double-walled cell that behaves in a way such that the inner cell reinforces the outer cell and vice versa. These cells are located on a base honeycomb sandwich panel in a hexagonal manner, structurally maximizing the design. (U.S. Patent 7,208,063)

The technology has broad potential for future aircraft applications. The Air Force is considering supersonic vehicles that have unique structural requirements. Aerodynamic performance constraints drive the design of these vehicles toward longer, sleeker configurations with thin fuselages, wings and tails (i.e. Concord and SR-7l). The design of future high-speed aircraft will continue to be driven by the desire to significantly reduce the structural weight of the aircraft while maintaining or increasing structural strength and stiffness.

ARDLs Hex-D/T honeycomb superstructure technology exhibits double the structural stiffness of conventional cores at the same core weight. This allows for thinner, lower weight, structural designs.

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Hex-D/T Honeycomb Superstructure U.S. Patent 7,208,063 (cont.)

These characteristics are the foundation for this honeycomb superstructure that has better performance and added durability. This double-walled, repeated structure can be manufactured using a forming technique or a corrugated joining process where the final shape of the inner and outer cells can be an ellipse/circle/polygon. It is the way the double-walled cells are organized within the hexagonal superstructure that causes ARDLs Hex-D/T honeycomb core to exhibit such unique properties.

ARDLs Hex-D/T Honeycomb Superstructure Also Exhibits the Following Advantages:

Ability to Reinforce in Response to Stress Peaks (Flexibility in Design)

Ballistic Resistant Corrosion Resistant

Costs Less to Make than Specialty-Material Based Honeycomb Structures

Enhances Properties of Celled Structure (Impact, Shear, Compression, etc.)

High Energy Absorbing Capacity High Modulus

High Stiffness Low Weight

Machining / Forming Manufacturability Moisture Resistant Multi-Solution Product PCF Flexibility (Optimum Placement of Tubes ) Shock Mitigation Properties Stronger Core-Skin Bond Due to Larger Surface in Contact with Facing Suitable for Various Engineering Requirements Superior Resistance to Impact Damage Support Against Damage Propagation by Containment of Damage within Superstructure

Unstabilized Honeycomb Core Plate Shear DataUltimate Force vs. Deflection

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

11000

12000

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.11 0.12 0.13 0.14 0.15 0.16 0.17 0.18

Deflection (in)

Load

(Lbf

) Hex-T (W) 10150 psi1/4-HRP Paper (W) 2470 psi

3/16-HRP Paper 3227 psiAluminum 3903 psiHex-T (L) 12072 psi

1/4-HRP Paper (L) 3995 psi

HexT-L

HexT-W

1/4-HRP-W

1/4 -HRP-L

3/16-HRP

Aluminum

Unstabilized Honeycomb Core Plate Shear DataUltimate Force vs Deflection