The number of flights expected for the next 2 decades shows a an annual growth rate of 4.7%, but needs to satisfy very tight constrains on fuel consumption (with fuel consumption being about 30% of the operating cost). It is required to strongly reduce fuel consumption of the future aircrafts manufactured.
One of the approaches required to do so is the introduction of advanced materials to reduce their weight, and composite materials in particular. Major manufacturers have increased the content of composite materials from 5% (A300) to 52% (A350XWB) for AIRBUS or to 46% for the CSeries (Bombardier), including wings, fuselage, and other structural parts etc.
Traditionally, structural components in aerospace have used carbon fiber pre-impregnated with epoxy resins (pre-pregs) that require to be cured in an Autoclave. Although the properties of the pre-pregs are outstanding, the cost associated to the maintenance, shelf life and autoclave processing of these pre-pregs represents a high percentage of the total cost of the part.
In order to reduce these costs, a strong effort has been performed to develop dry composite materials with suitable material properties, and reduced manufacturing costs due to higher deposition rates, no costs of refrigeration, and longer shelf life. Due to this effort, the use of dry composite materials emerges as a new material feasible for the manufacture of structural components.
The CSeries Aircrafts, from Bombardier Aerospace represents a breakthrough in the use of composite materials, since some of their structural components, such us the wings are being manufactured using dry composite materials. Bombardier expects to reduce 20% the fuel consumption, and have 25% less maintenance costs. The CSeries aircraft is expected to make the first flight shortly. In particular, the manufacturing process is based on pick and place of dry composite material cut on a 2D table and positioned in the mould.
Bombardier is not the only one aircraft manufacturer that uses dry composites in the design of the new aircraft to reduce costs and increase productivities: A400M from AIRBUS cargo door (also a structural component) is also manufactured using dry composite materials. Furthermore, their manufacturing method uses alternatives to autoclave, by means of the VAP (vacuum-assisted process) demonstrating that dry composite materials can achieve mechanical properties required to be used in structural components. The manufacture of these components also takes benefit of the combined infusion of the different parts (skin and stringers), avoiding about 3000 metallic rivets.
The investigation and development on dry composites, offers a critical opportunity to push forward the presence of composite materials in the aeronautic field by reducing costs, and maintaining the mechanical properties of pre-preg materials.
Airbus and Bombardier are setting up the first steps regarding the use of dry composites in the aeronautic sector. This sets the path to the industrial development of processing technologies of the fabrication of the materials and the components, and moving from manual manufacturing for short series to high production for larger series, as has happened with glass fiber or pre-preg carbon fiber materials.
There are still strong challenges remaining to take full advantage of this disruptive material that require a strong synergy between all the agents responsible of the introduction, design and development of components manufactured from dry composite materials: companies, Research Centers, academics and experts.