1Materials For AIRCRAFTS
Presented by
Jabin Mathew Benjamin
13MY04
Dept. of Metallurgical Engineering
2Indian aviation industry
• Passenger traffic: 160 million in 2013
• Freight traffic: 2.2 million tonnes in 2013
• Aircrafts: fastest mode of transport
• Major role in defence
• Safety main concern• Environment and mechanical conditions
3MATERIALS FOR AIRCRAFTS
• Function• Carry passenger and cargo load via air route
• Constraints• Factor of safety (1.2 - 3)• Corrosion resistant
• Objectives• Maximize strength • Minimize mass
• Free variables• Material• Cost
4Material indices
Strength to weight ratio or specific strength
Maximize ( / s r)
5Screening
Source: Figure 4.4, Micheal F. Ashby, Materials selection in mechanical design, 3 rd edition, 2005 [1]
61903 - First Flight - The Wright Brothers
• Wood - natural composite - high strength to weight ratio
• Easy to work • Tough and flexible
• Moisture absorption• Anisotropic
[2]
71915 – First all-metal Junkers J-1
• Steel
• Weight – sluggish• Unmaneuverable in flight
• Wtal = 1/3 wts
[2]
8 1917 - Junkers J-7
• Duralumin – Al, 4% Cu, Mg and Mn
• Al – 2024, 7075
• Subsonic aircraft
• US Navy – Alclad• duralumin with pure aluminum coating
• Al-Li alloys • Airbus A350 - wings and fuselage
• Supersonic - elevated temperatures
• Aluminium – low heat resistance
Source: Figure 4.4, Micheal F. Ashby, Materials selection in mechanical design, 3 rd edition, 2005 [1]
9Titanium
• High strength
• 40% lighter than steel
• Good creep properties
SR-71 Blackbird - highest flying, fastest aircraft(wings and fuselage – titanium)
10Composite
Fibreglass - Boeing 707 - 1950s – 2% of the structure• Weight reduction• High corrosion resistance• Good fatigue strength• Reducing operating costs - fuel• Improved efficiency
• GLAss-REinforced” Fiber Metal Laminate (FML)• Good impact and fatigue strength• Better corrosion resistance• Better fire resistance• Lower specific weight
112009 – Boeing 787 Dreamliner
Weight breakdown by material type:
50% composite (fuselage, wings, tail, doors and interior)
20% aluminum (wing and tail leading edges)
15% titanium (engines components)
10% steel (various locations)
5% other
• 80% composite by volume
• 20% more efficient than the 767
12The Tejas – India’s indigenous LCA
• CFC upto 45%• Fuselage (doors and skins)• Wings (skin, spars and ribs)• Tailfin, rudder, air brakes and landing gear
doors.• Fewer joints or rivets
• 40% reduction - number of parts
• Weight lowered by 21%
• Shorter time to assemble• 7 months as opposed to 11 months using an
all-metal airframe.
Source: http://www.tejas.gov.in/technology/composite_materials.html
13Reference
1. Micheal F. Ashby, Materials Selection In Mechanical Design, 3rd Edition, 2005
2. Peter L. Jakab, Wood To Metal: The Structural Origins of The Modern Airplane, Journal of Aircraft, Vol. 36, No. 6, November – December 1999\
3. Júlio C. O. Lopes, Material Selection For Aeronautical Structural Application, Ciência & Tecnologia Dos Materiais, Vol. 20, 2008
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