Faster, lighter, stronger: Aerospace composites join together advanced materials

Boeing and Airbus forecast a worldwide demand for up to 40,000 new aircraft over the next two decades. With a 10-year production backlog and new aircraft increasingly depending on lightweight composites, manufacturing companies are developing advanced solutions to fill the gap.

One facet of the lightweight composite material push is development of sandwich-structure composites; made by “sandwiching” a thick, lightweight core between two thin sheets of stiff material. These types of composite materials possess low overall density, high bending stiffness, and often good thermal insulation—excellent qualities for aerospace applications.

To accelerate production of sandwich composites, Belgium-based EconCore has developed a process for rapidly producing high performance lightweight thermoplastic honeycomb cores.

The company’s ThermHex process allows for production from a single continuous piece of thermoplastic sheet by successive in-line thermoforming, folding, and bonding operations. EconCore says that it can perform this process directly from an extruder or material roll.

To leverage this capability, EconCore partnered with Diehl Aircabin, to develop aircraft interior modules under a European Commission funded project.

The new development brings together EconCore’s honeycomb production technology with a special grade of polycarbonate that has outstanding fire, smoke, and toxicity (FST) performance. Polycarbonates have been used extensively in the aerospace industry because of their low weight and high impact resistance. Optically transparent polycarbonates are often used in impact resistant window and cockpit glass applications, such as the Lockheed Martine F-22 Raptor canopy.

EconCore has been developing and testing honeycomb cores made from modified polycarbonates, polyamide 66, and polyphenylene sulfide and is now entering the final phase of validating these thermoplastics.

Test reports confirm the excellent fire-resistant behavior of the final polycarbonate sandwich structures, which cost significantly less than aramid and other conventional honeycomb solutions. This year, EconCore is targeting new polycarbonate application developments in markets of automotive, aerospace, transportation, packaging, and construction.

“We are excited about taking this development forward to create mono-material thermoplastic honeycomb sandwich panels that could be very efficiently one-shot thermoformed and functionalized into final aircraft interior modules,” said Tomasz Czarnecki, COO of EconCore.

Where EconCore is developing techniques for manufacturing composite cores, Henkel—the German chemical and consumer good company—aims to demonstrate its expertise in developing advanced potting compounds for joining the honeycomb sandwich assemblies under its Loctite brand.

Often manufacturers use adhesives, rivets, and potted inserts when joining the components to this honeycomb composite surface. Potting compound is used to provide mechanical reinforcement to housed assemblies and fill voids. The compounds also protect and insulate devices from the effects of exposure to chemicals, moisture, mechanical shock, thermal stress, and vibration.

The new compounds have proven micro-cracking resistance, density/strength ratio, and flame retardancy over conventional potting compounds. These characteristics make the new potting compound ideal for aircraft primary and secondary structures (such as fuselage and wing components) and interior panel applications.

Henkel recently began construction of a new production facility for aerospace materials at its site in Montornès del Vallès, Spain. The facility will include new buildings and equipment for additional production and warehouse capacities to further support key trends in the industry such as light weighting and automation. Due to the proximity to several sites of global key customer Airbus, Montornès will become Henkel’s European hub for the aerospace industry.

Both EconCore and Henkel will be presenting their latest technologies at JEC World 2018 in Paris this March. JEC World is an international tradeshow that exclusively focuses on composite materials.

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