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Yogan Naidu

University of KwaZulu Natal

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Composites in Aircraft Structures

Composite material: two or more materials that are integrated to

form a new material

Learjet 85

Boeing Dreamliner

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Motivation

ACARE Guidelines halving CO2 emissions in half

Decrease empty weight ratio (Me/Mto)

Increase useful load capacity

Thinner wings without structural penalties

Higher AR wings can be built

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Project Aims To research and study the materials commonly used for aerospace

structures and the composite materials that may be used to replacethem

To study the ways in which composite materials have been appliedin already existing aircraft structures

To design a Medium Sized UAV Structure for ISR missions whosestructure can be built using composite materials

To optimize the wing structure of the UAV with Hypersizer forminimum weight

To compare the weight savings that exist between metallic andcomposite wing structures

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Materials

CFRP

High tensile strength

Low density (compared to aerospace grade aluminium)

Fatigue Immunity

+/- 45 plies for shear loading

0 and 90 plies for direct loading (span- and chord-wise loading)

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Wing Loads

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Software Hypersizer

Optimize the fibre layup and orientations

Achieve a minimum weight optimization

Optimize wing using unidirectional carbon fibres and Nomexhoneycomb stiffeners

MSC SimXpert

Perform FEA Set up initial mesh

Provide FE Model for optimization procedure

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Aircraft layout

Conventional Layout

High AR Wings

High L/D value (approx 22)

Single, rear mounted piston engine

Mission Time 10 hours

Altitude 25 000 feet

Interchangeable Payload(Up to 100kgs)

Take-off Weight - 406kgs

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Wing Geometry

Geometry Value

Wing Area 6 m2

Aspect Ratio (AR) 15

Wing Span 9.5 m

Wing Sweep n/a

Wing thickness Ratio 12%

Max CL 1.67

Root chord length 0.63 m

Tip chord length 0.30 m

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Catia Model

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Preliminary Results

Meshed Wing Surface

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Ply Directions

Translational Displacements

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Von Mises Stress Tensor

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Conclusions

Composites are the forefront of aircraft structures technology

Next generation UAVs and civil aircraft are all being designed withcomposites

Legislative and economic benefits

Wing design for a MALE UAV

Preliminary FEA underway

Structural Optimization and verification still to be completed

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Acknowledgements

Prof. Sarp AdaliBSc Eng (METechU), PhD (Cornell), FASME, FRSSAFSugar Millers Chair of Mechanical Design

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References

[1] T. Edwards, "Composite materials revolutioniseaerospace engineering," INGENIA, September2008

[2] T. Edwards, "Composite materials developmentunder the NGCW research program."

[3] R. Phillips, "Electrostatic discharge in carbonfibre aircraft " 2010.

[4] W. F. Smith and J. Hashemi, Foundations ofMaterial Science and Engineering4th ed. New

York: McGraw Hill, 2006. [5] C. Reed, "The outlook for unmanned aircraft,"

High Performance Composites, May 2009 2009. [6] E. Guizzo, "Winner Carbon Takeoff," IEEE

SpectrumJanuary 2006 2006.