|The CentrAl construction. Click to enlarge.|
A new special aluminum-fiber combination material (Central Reinforced Aluminum, CentrAl) for aircraft wings that makes them nearly immune to metal fatigue could contribute significantly to lower fuel consumption by reducing the weight of conventional constructions.
Fatigue is a phenomenon that affects materials after long-term exposure to cyclic loading. As a result of varying loads, fractures eventually occur. The new CentrAl constructions are stronger than the carbon fiber reinforced plastic (CFRP) constructions that have recently been used in aircraft wings such as the Boeing 787. By using CentrAl wing constructions, the weight can be reduced by 20% compared to CFRP constructions. Furthermore, using CentrAl results in considerably lower manufacturing and maintenance costs.
The CentrAl concept comprises a central layer of fiber metal laminate (FML), sandwiched between one or more thick layers of high-quality aluminum. This creates a robust construction material which is not only exceptionally strong, but also insensitive to fatigue. The CentrAl technique enables simple repairs to be carried out immediately, as is the case in aluminum constructions, but not the case when using CFRP constructions.
This patented new concept is one of the results of a collaboration between the company GTM Advanced Structures, founded in The Hague in 2004 and specializing in new aircraft materials and constructions; Alcoa; and the Faculty of Aerospace Engineering of Delft University of Technology.
GTM and Alcoa presented the new concept to international experts in the field of metal fatigue and damage sensitivity of aircraft constructions at a conference in Delft (Conference on Damage Tolerance of Aircraft Structures: 25-28 September 2007).
The US Air Force, Alcoa and GTM will also discuss the possibilities for the use of the new CentrAl material to create ‘Carefree structures’. These are aircraft constructions that are less sensitive to damage caused, for example, by fatigue, hail storms, other weather phenomena, trucks that collide with the aircraft and corrosion. Carefree aircraft constructions will be characterized by significantly reduced maintenance costs.