GLARE (material)
Encyclopedia
GLARE is a "Glass Laminate Aluminium Reinforced Epoxy" FML
, composed of several very thin layers of metal (usually aluminium
) interspersed with layers of glass-fibre "pre-preg
", bonded together with a matrix such as epoxy
. The uni-directional pre-preg layers may be aligned in different directions to suit the predicted stress
conditions.
Although GLARE is a composite material
, its material properties and fabrication are very similar to bulk aluminum metal sheets. It has far less in common with composite structures when it comes to design, manufacture, inspection or maintenance. GLARE parts are constructed and repaired using mostly conventional metal material techniques.
Its major advantages over conventional aluminium are:
Furthermore, it is possible to "tailor" the material during design and manufacture such that the number, type and alignment of layers can suit the local stresses and shapes throughout the aircraft. This allows the production of double-curved sections, complex integrated panels or very large sheets, for example.
While a simple manufactured sheet of GLARE will be more expensive than an equivalent sheet of aluminium, considerable production savings can be made using the aforementioned optimization. A structure properly designed for GLARE will be significantly lighter and less complex than an equivalent metal structure, and will require less inspection and maintenance and enjoy a much longer lifetime-till failure, making it a cheaper, lighter and safer option overall.
, patented by Akzo Nobel
in 1987 and now entering commercial application in the Airbus A380
, which has recently received a full type certificate from the FAA
and European Aviation Authorities
. The patent cites as inventors Roebroeks and Vogelesang, two former professors at the aerospace engineering faculty of Delft University of Technology
, where much of the for GLARE was done in the 1970s and 1980s.
|
The fruition of FML development marks the end of a long history of research starting in 1945 at Fokker
, where earlier bonding experience at de Havilland inspired investigation into the improved properties of bonded aluminium laminates compared to monolithic aluminium.
Later, NASA
got interested in reinforcing metal parts with composite materials as part of the Space Shuttle
programme led to the introduction of fibres to the bond layers, and the concept of Fibre Metal Laminates was born.
Further research and co-operation with Delft University
, the Dutch Aerospace Laboratory NLR, Alcoa
and various other companies and institutions led to the first FML, the Aramid
-fibre
based ARALL. This proved to have some cost, manufacturing and application problems (while it had a very high tensile strength; compression, off-axis loading and cyclic loading proved problematic).
As a footnote, GLARE is also the material used in the ECOS3 blast-resistant Unit Load Device
. This is the only commercially available container shown to completely contain the explosion and fire resulting from a bomb such as that used over Lockerbie
.
in Wrexham, UK who supplies it to the Airbus A380
component manufacturing facilities at Stork
Fokker in the Netherlands as well as at Airbus in Nordenham, Germany. Stork Fokker has opened a brand new facility next to its existing facilities in Papendrecht, the Netherlands. There Stork Fokker is able to produce Glare sheets of including the milling of doors windows etc. on a state-of-the-art 5-axis milling machine with a movable bed.
Glare has also been used in manufacturing of the cargo doors of the latest models of the C-17 Globemaster III
.
Fibre Metal Laminate
A Fibre Metal Laminate is one of a class of metallic materials consisting of a laminate of several thin metal layers bonded with layers of composite material...
, composed of several very thin layers of metal (usually aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
) interspersed with layers of glass-fibre "pre-preg
Pre-preg
Pre-preg is a term for "pre-impregnated" composite fibres. These usually take the form of a weave or are uni-directional. They already contain an amount of the matrix material used to bond them together and to other components during manufacture. The pre-preg are mostly stored in cooled areas since...
", bonded together with a matrix such as epoxy
Epoxy
Epoxy, also known as polyepoxide, is a thermosetting polymer formed from reaction of an epoxide "resin" with polyamine "hardener". Epoxy has a wide range of applications, including fiber-reinforced plastic materials and general purpose adhesives....
. The uni-directional pre-preg layers may be aligned in different directions to suit the predicted stress
Stress (physics)
In continuum mechanics, stress is a measure of the internal forces acting within a deformable body. Quantitatively, it is a measure of the average force per unit area of a surface within the body on which internal forces act. These internal forces are a reaction to external forces applied on the body...
conditions.
Although GLARE is a composite material
Composite material
Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...
, its material properties and fabrication are very similar to bulk aluminum metal sheets. It has far less in common with composite structures when it comes to design, manufacture, inspection or maintenance. GLARE parts are constructed and repaired using mostly conventional metal material techniques.
Its major advantages over conventional aluminium are:
- Better "damage toleranceDamage toleranceDamage tolerance is a property of a structure relating to its ability to sustain defects safely until repair can be effected. The approach to engineering design to account for damage tolerance is based on the assumption that flaws can exist in any structure and such flaws propagate with usage...
" behaviour (especially impact and metal fatigueMetal FatigueMetal Fatigue , is a futuristic science fiction, real-time strategy computer game developed by Zono Incorporated and published by Psygnosis and TalonSoft .-Plot:...
, as the elastic strain is larger than other metal material it can consume more impact energy. It is dented easier but has a higher penetration resistance )
- Better corrosionCorrosionCorrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...
resistance
- Better fireFireFire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....
resistance
- Lower specific weightSpecific weightThe specific weight is the weight per unit volume of a material. The symbol of specific weight is γ ....
Furthermore, it is possible to "tailor" the material during design and manufacture such that the number, type and alignment of layers can suit the local stresses and shapes throughout the aircraft. This allows the production of double-curved sections, complex integrated panels or very large sheets, for example.
While a simple manufactured sheet of GLARE will be more expensive than an equivalent sheet of aluminium, considerable production savings can be made using the aforementioned optimization. A structure properly designed for GLARE will be significantly lighter and less complex than an equivalent metal structure, and will require less inspection and maintenance and enjoy a much longer lifetime-till failure, making it a cheaper, lighter and safer option overall.
History
GLARE is currently (2004) the most successful FMLFibre Metal Laminate
A Fibre Metal Laminate is one of a class of metallic materials consisting of a laminate of several thin metal layers bonded with layers of composite material...
, patented by Akzo Nobel
Akzo Nobel
Akzo Nobel N.V., trading as AkzoNobel, is a Dutch multinational, active in the fields of decorative paints, performance coatings and specialty chemicals. Headquartered in Amsterdam, the company has activities in more than 80 countries, and employs approximately 55,000 people. Sales in 2010 were EUR...
in 1987 and now entering commercial application in the Airbus A380
Airbus A380
The Airbus A380 is a double-deck, wide-body, four-engine jet airliner manufactured by the European corporation Airbus, a subsidiary of EADS. It is the largest passenger airliner in the world. Due to its size, many airports had to modify and improve facilities to accommodate it...
, which has recently received a full type certificate from the FAA
Federal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...
and European Aviation Authorities
Joint Aviation Authorities
The Joint Aviation Authorities, or JAA, was an associated body of the ECAC representing the civil aviation regulatory authorities of a number of European States who had agreed to co-operate in developing and implementing common safety regulatory standards and procedures...
. The patent cites as inventors Roebroeks and Vogelesang, two former professors at the aerospace engineering faculty of Delft University of Technology
Delft University of Technology
Delft University of Technology , also known as TU Delft, is the largest and oldest Dutch public technical university, located in Delft, Netherlands...
, where much of the for GLARE was done in the 1970s and 1980s.
|
The fruition of FML development marks the end of a long history of research starting in 1945 at Fokker
Fokker
Fokker was a Dutch aircraft manufacturer named after its founder, Anthony Fokker. The company operated under several different names, starting out in 1912 in Schwerin, Germany, moving to the Netherlands in 1919....
, where earlier bonding experience at de Havilland inspired investigation into the improved properties of bonded aluminium laminates compared to monolithic aluminium.
Later, NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
got interested in reinforcing metal parts with composite materials as part of the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
programme led to the introduction of fibres to the bond layers, and the concept of Fibre Metal Laminates was born.
Further research and co-operation with Delft University
Delft University of Technology
Delft University of Technology , also known as TU Delft, is the largest and oldest Dutch public technical university, located in Delft, Netherlands...
, the Dutch Aerospace Laboratory NLR, Alcoa
Alcoa
Alcoa Inc. is the world's third largest producer of aluminum, behind Rio Tinto Alcan and Rusal. From its operational headquarters in Pittsburgh, Pennsylvania, Alcoa conducts operations in 31 countries...
and various other companies and institutions led to the first FML, the Aramid
Aramid
Aramid fibers are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic rated body armor fabric and ballistic composites, in bicycle tires, and as an asbestos substitute. The name is a portmanteau of "aromatic polyamide"...
-fibre
Fiber
Fiber is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.They are very important in the biology of both plants and animals, for holding tissues together....
based ARALL. This proved to have some cost, manufacturing and application problems (while it had a very high tensile strength; compression, off-axis loading and cyclic loading proved problematic).
As a footnote, GLARE is also the material used in the ECOS3 blast-resistant Unit Load Device
Unit Load Device
A unit load device , is a pallet or container used to load luggage, freight, and mail on wide-body aircraft and specific narrow-body aircraft. It allows a large quantity of cargo to be bundled into a single unit. Since this leads to fewer units to load, it saves ground crews time and effort and...
. This is the only commercially available container shown to completely contain the explosion and fire resulting from a bomb such as that used over Lockerbie
Pan Am Flight 103
Pan Am Flight 103 was Pan American World Airways' third daily scheduled transatlantic flight from London Heathrow Airport to New York's John F. Kennedy International Airport...
.
Current production
GLARE is currently produced by Cytec Engineered MaterialsCytec Industries
Cytec Industries Incorporated, based in Woodland Park is a speciality chemicals and materials technology company with pro-forma sales in 2004, including the Surface Specialties acquisition, of approximately $3.0 billion. Cytec is a result of its spin-off from American Cyanamid Company...
in Wrexham, UK who supplies it to the Airbus A380
Airbus A380
The Airbus A380 is a double-deck, wide-body, four-engine jet airliner manufactured by the European corporation Airbus, a subsidiary of EADS. It is the largest passenger airliner in the world. Due to its size, many airports had to modify and improve facilities to accommodate it...
component manufacturing facilities at Stork
Stork N.V.
Stork B.V. is a Dutch manufacturing and service providing company with its headquarters in Naarden. It was founded in 1868 by Charles Theodoor Stork, although in the 20th century the company merged other companies some, including Werkspoor, founded in 1827 as Nederlandse Fabriek van Werktuigen en...
Fokker in the Netherlands as well as at Airbus in Nordenham, Germany. Stork Fokker has opened a brand new facility next to its existing facilities in Papendrecht, the Netherlands. There Stork Fokker is able to produce Glare sheets of including the milling of doors windows etc. on a state-of-the-art 5-axis milling machine with a movable bed.
See also
- Airbus A380Airbus A380The Airbus A380 is a double-deck, wide-body, four-engine jet airliner manufactured by the European corporation Airbus, a subsidiary of EADS. It is the largest passenger airliner in the world. Due to its size, many airports had to modify and improve facilities to accommodate it...
- CheFEM
Glare has also been used in manufacturing of the cargo doors of the latest models of the C-17 Globemaster III
C-17 Globemaster III
The Boeing C-17 Globemaster III is a large military transport aircraft. Developed for the United States Air Force from the 1980s to the early 1990s by McDonnell Douglas, the C-17 is used for rapid strategic airlift of troops and cargo to main operating bases or forward operating bases throughout...
.