materials for aircrafts
DESCRIPTION
materials for aircrafts, their selection, criteria for selection and evolution of aircraft materials over the yearsTRANSCRIPT
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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