Composites

1. COMPOSITE MATERIALS IN
AIRCRAFT STRUCTURES
Prepared By:
RAHUL DUBEY

2. Overview
 Composite Materials: A Brief Introduction
Why Composites?
Advantages of Composites
Applications in Aerospace Industry
Limitations of Composites
Conclusion
References

3. Introduction
Modern technologies require materials with
unusual combination of properties
Cannot be met by conventional materials.
 Aerospace EngineeringApplications
 Low density, strong & stiff, and abrasion,
corrosion & impact resistant material.

4. Composite Materials
Material property combinations have been
extended
Exhibit a significant proportion of properties of
constituent phases
Number of composites occur in nature
1.Wood
 Strong & flexible cellulose fibers held together
by stiffer lignin
2. Bone
 Soft & strong collagen surrounds hard & brittle
apatite

5. Definition
 A composite material in the present context
 A combination of two or more materials with certain
desired properties or improved properties
 The original identity of dispersed (reinforcement)
phase should be retained during manufacturing
and/service
 Multiphase alloys & ceramics are not composites
 Most composites have been created to improve the
combination of mechanical properties
 Stiffness, toughness, ambient & high temperature
strength

6. Why Composites?
To enhance the material properties &
performance efficiency
To design materials with combination of
desired properties

7. Advantages of Composites
 High strength/stiffness to weight ratio
 Energy efficient
 Corrosion and weather resistant
 Properties for specific design conditions
 Directional properties
 Easy to make complex shapes

8. Constituents
 Reinforcement - Discontinuous phase
(constituent)
 Matrix - Continuous phase (constituent)
Polymer Composite

9. Constituents
Reinforcements
 principal load bearing member
Matrix
 provides a medium for binding and holding the
reinforcements or fillers together into a solid
 protects the reinforcement from environmental
degradation
 serves to transfer load from one insert (fibre,
flake or particles) to the other
 provides finish, colour, texture, durability and
other functional properties

11. Classification
Nature of Origin
 Natural Composites
 Man-made Composites
Matrix
 Polymer Matrix Composites (PMC)
 Metal Matrix Composites (MMC)
 Ceramic Matrix Composites (CMC)
Reinforcements
 Fibre & Particulate Composites
 Macro-, Micro- and Nano-composites

12. Purpose of Second Phase
to enhance matrix properties
 PMC: to increase E, σy,TS, creep resistance
 MMC: to increase σy,TS, creep resistance
 CMC: to increase Kc

15. Applications of Composites in
Aerospace
Starting with first fully-composite glider
“phonix”, Fibre reinforced plastics (FRPs)
have gained importance in aerospace
industry.
2000 tons of finished composite parts, with a
value of 760 million dollars were produced by
European aerospace industry in 2000.

17. V/STOL (vertical and/or short take-off and landing); SST (supersonic transport)

18. Composites in Military
Aircraft
Aircraft Component Material Weight
Saving
(%)
F-14 Skin on the horizontal
stabiliser box
B-Epoxy 19
F-11 Underwing fairings C-Epoxy -
F-15 Fin, stabiliser skins B-Epoxy 25
F-16 Skins on vertical fin box, Fin
leading edge
C-Epoxy 23
F/A-18 Wing skins, Horizontal &
vertical tail boxes, wing & tail
control surfaces
C-Epoxy 35
AV-8B Wing skins & sub structures,
forward fuselage, horizontal
stabiliser, ailerons
C-Epoxy 25

22. Limitations of Composites
 Composites are more expensive than conventional
materials on a cost to cost basis
 The chances of formation of defects at the interface
are high
 Most of the fibre reinforced composites are
anisotropic in nature
 The production rate of composites is generally low
 Database on the properties of different composites
is not available
 Recycling is another hurdle for the wide usage of
 composites

24. In Conclusion...

25. References
 Agarwal, B.D., L.J. Broutman and K. Chandrashekhara.
2006. Analysis and performance of fiber composites, 3rd edn.,
NewYork:JohnWiley & sons.
 Chawla, K.K. 2012. Composite materials:Science and
engineering, 3rd edn., NewYork, USA: Springer-Verlag Inc.
 Mallick, P.K. 2008. Fiber-reinforced composites, 3rd edn.,
Boca Raton, USA: CRC Press.
 Ajayan, P.M., L.S. Schadler and P.V. Braun. 2003.
Nanocomposite science and technology, Morlenbach,
Germany:WILEY-VCH.
 Balasubramanian, M. 2013. Composite materials and
processing, Boca Raton, USA: CRC Press.
 Suresh, S., Mortensen,A. and Needleman,A. (Eds.) 1993.
Fundamentals