Natural honeycomb structures occur in many different environments, from beehives to honeycomb weathering in rocks. Based on these, man-made honeycomb structures have been built with similar geometry to allow the reduction of the quantity of material used, and thereby realizing minimal weight and material cost.
Man-made honeycomb structures have an array of hollow cells formed between thin vertical walls, so that the material has minimal density, strength in tension and high out-of-plane compression properties.
How are Honeycomb Composites Manufactured?
Honeycomb structures are manufactured using three conventional methods, namely, expansion, corrugation and molding, which can be traced back to the 1900s.
Today, the manufacture of honeycomb cores involves the use of the expansion and corrugation processes where composite materials such as fibreglass, aluminium, and carbon fiber reinforced plastic are used. To manufacture thermoplastic honeycomb cores, the raw material used is polypropylene and the method used is extrusion.
A more recent cost efficient method for the manufacture of thermoplastic honeycomb structures enables continuous in-line production and direct lamination of skin. Similarly, continuous in-line production of metal honeycomb can also be performed from metal rolls by cutting and bending.
Apart from metal honeycomb composite structures, there are also paperboard honeycomb materials that are being manufactured for use in paper pallets and package blocking, cushioning, and bracing.
Companies Involved in Honeycomb Composites Manufacturing
The following is a list of companies manufacturing a variety of honeycomb composite materials with a brief introduction to each:
Corex-Honeycomb is a UK-based company producing high-quality aluminium honeycomb core for use in a wide variety of applications including marine, defence, aerospace, rail, and automotive industries. Aluminium honeycomb is in high demand due to its excellent high strength-to-weight ratio, and also in areas where minimal weight and strength are required.
Dupont is involved in the manufacture of two types of honeycomb composites, namely, DuPont™ Nomex ® and Kevlar ®. Both products possess stiffness, toughness, strength, corrosion resistance and lightweight characteristics, which make these products a high-demand material for industries such as construction, mass transportation, and marine shipping. For example, in aircraft construction, thin Nomex ® honeycomb sandwich composite sheets are used in aircraft parts such as interior walls, storage bins, flooring panels, engine nacelles, exterior control surfaces, and helicopter blades and tail booms. Likewise in the transportation industry, these lightweight honeycomb composite structures have helped provide cost-effective benefits such as energy savings.
3A Composites GmbH produces ALUCORE ®, which is an aluminium composite panel comprising two cover sheets and a honeycomb core of aluminium. ALUCORE ® is available in a variety of colors, and has exceptional flatness and high formability. This composite material finds application in many fields such as in transport, industry, and architecture. The aluminium honeycomb core provides the material with high rigidity and minimal weight. This material is thus popular for use as façade cladding or roofing especially in places with high levels of wind.
Amber Composites is a UK-based company involved in the manufacture of high-performance composite materials. This company was recently acquired by TenCate Group, a global supplier of advanced composite materials for the anti-ballistics aerospace industry, and a wide range of industrial applications.
Benefits of Honeycomb Composites
The key benefits of using honeycomb composites are given below:
Exceptional strength to weight ratio
Fire and fungus resistant
High temperature performance
Does not absorb moisture
Easily machinable and formable
Provides cost-effective benefits like energy savings
Aluminum honeycomb provides maximum stiffness with one of the highest strength to weight ratios of any structural core material in the market.
Kevlar™ honeycomb conforms to strict smoke, toxicity and flammability standards.
Honeycomb materials can be used in a huge number of applications. Some of the common applications are as follows:
Skis and snowboards
Rocket substructure and jet aircraft
LED technology and loudspeaker technology
Air, water, fluid, and light directionalisation
Electric shielding enclosures
Wind turbine blades
Clean room panels and exterior architectural curtain wall panels
Heating, ventilation, air-conditioning equipment and devices
Energy absorption protective structures
In the construction of boats for providing buoyancy that will help enhance speed
In the rail industry for forming doors, floors, energy absorbers/bumpers, and furniture
In the marine industry for constructing commercial vessels and naval vessel bulkheads, wall ceiling, partition panels, furniture, and several other applications
Sources and Further Reading