The document discusses materials used for aircrafts and how they have evolved over time. It begins by providing background on the Indian aviation industry and objectives for aircraft materials such as maximizing strength while minimizing mass. Various materials are then examined, including wood in early planes, steel and duralumin in early 20th century planes, aluminum and titanium in subsonic and supersonic planes, and increasing use of composites such as fiberglass and carbon fiber composites in modern planes like the Boeing 787 and India's Tejas aircraft. Composites provide benefits like reduced weight, improved efficiency and lower assembly time.

1. Materials For
AIRCRAFTS
Presented by
Jabin Mathew Benjamin
13MY04
Dept. of Metallurgical Engineering
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2. Indian 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
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3. MATERIALS 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
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4. Material indices
Strength to weight ratio or specific strength
Maximize (s / r)
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5. Screening 5
Source: Figure 4.4, Micheal F. Ashby, Materials selection in mechanical design, 3rd edition, 2005 [1]

6. 1903 - First Flight - The Wright Brothers
• Wood - natural composite - high strength to
weight ratio
• Easy to work
• Tough and flexible
• Moisture absorption
• Anisotropic
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[2]

7. 1915 – First all-metal Junkers J-1
• Steel
• Weight – sluggish
• Unmaneuverable in flight
• Wtal = 1/3 wts
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[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
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Source: Figure 4.4, Micheal F. Ashby, Materials selection in mechanical design, 3rd edition,
2005 [1]

9. Titanium 9
• High strength
• 40% lighter than steel
• Good creep properties
SR-71 Blackbird - highest flying, fastest aircraft
(wings and fuselage – titanium)

10. Composite
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
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11. 2009 – 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
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12. The 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.
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Source: http://www.tejas.gov.in/technology/composite_materials.html

13. Reference
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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