Composite Materials in Aircraft Structures

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 Engineering Applications 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

10. 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

11. Purpose of Second Phase to enhance matrix properties PMC: to increase E, σ y, TS, creep resistance MMC: to increase σ y, TS, creep resistance CMC: to increase Kc

12. 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.

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

14. 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

15. 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

16. In Conclusion...

17. References Agarwal , B.D., L.J. Broutman and K. Chandrashekhara . 2006. Analysis and performance of fiber composites, 3rd edn ., New York: John Wiley & sons. Chawla , K.K. 2012. Composite materials: Science and engineering, 3 rd edn ., New York, 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