The Question: Which aircraft has the highest weight ratio for CFRP?
The Airbus A350 XWB is built of 52% Carbon Fibre Reinforced Polymer (CFRP) including wing spars and fuselage components, overtaking the Boeing 787 Dreamliner, for the aircraft with the highest weight ratio for CFRP, which was held at 50%.
This was one of the first commercial aircraft to have the wing spars made from composites.
The Airbus A380 was one of the first commercial airliner to have a central wing box made of CFRP; it is the first to have a smoothly contoured wing cross section instead of the wings being partitioned span-wise into sections. This flowing, continuous cross section optimises aerodynamic efficiency. Moreover, the trailing edge along with the rear bulkhead, empennage and un-pressurized fuselage are made of CFRP.
Specialist aircraft designer and manufacturer Scaled Composites have made extensive use of CFRP throughout their design range including the first private manned spacecraft Spaceship One. CFRP is widely used in micro air vehicles (MAVs) because of its high strength to weight ratio.
SpaceX is using carbon fibre for the entire primary structure of their new super heavy-lift launch vehicle, the ITS launch vehicle—as well as the two very large spacecraft that will be launched by it, the Interplanetary Spaceship and the ITS tanker. This is a particular challenge for the large liquid oxygen tank structure due to design challenges of such dense carbon/oxygen contact for long periods of time.
Ultralight aircraft (see SSDR) such as the E-Go, rely heavily on CFRP in order to meet the category weight compliance requirement of less than 115 kg (254 lb) without pilot or fuel.
In civil engineering Retrofitting has become the increasingly dominant use of the material, and applications include increasing the load capacity of old structures (such as bridges) that were designed to tolerate far lower service loads than they are experiencing today, seismic retrofitting, and repair of damaged structures. Retrofitting is popular in many instances as the cost of replacing the deficient structure can greatly exceed its strengthening using CFRP.
Applied to reinforced concrete structures for flexure, CFRP typically has a large impact on strength (doubling or more the strength of the section is not uncommon), but only a moderate increase in stiffness (perhaps a 10% increase). This is because the material used in this application is typically very strong (e.g., 3000 MPa ultimate tensile strength, more than 10 times mild steel) but not particularly stiff (150 to 250 GPa, a little less than steel, is typical). As a consequence, only small cross-sectional areas of the material are used. Small areas of very high strength but moderate stiffness material will significantly increase strength, but not stiffness.
CFRP can also be applied to enhance shear strength of reinforced concrete by wrapping fabrics or fibers around the section to be strengthened. Wrapping around sections (such as bridge or building columns) can also enhance the ductility of the section, greatly increasing the resistance to collapse under earthquake loading. Such ‘seismic retrofit’ is the major application in earthquake-prone areas, since it is much more economic than alternative methods.
CFRP is now widely used in sports equipment such as in squash, tennis and badminton racquets, sport kite spars, high quality arrow shafts, hockey sticks, fishing rods, surfboards and rowing shells. Amputee athletes such as Oscar Pistorius use carbon fiber blades for running. It is used as a shank plate in some basketball sneakers to keep the foot stable, usually running the length of the shoe just above the sole and left exposed in some areas, usually in the arch.
Controversially, in 2006, cricket bats with a thin carbon-fiber layer on the back were introduced and used in competitive matches by high-profile players including Ricky Ponting and Michael Hussey. The carbon fiber was claimed merely to increase the durability of the bats but was banned from all first-class matches by the ICC in 2007.