lecture material on applications and current trends in composite materials.

1. Composite Materials-Composite Materials-
Research and ApplicationsResearch and Applications
Dr. K. Padmanabhan, FIIPE, FIE, CE(I), FISME.Dr. K. Padmanabhan, FIIPE, FIE, CE(I), FISME.
ProfessorProfessor
School of Mechanical and Building SciencesSchool of Mechanical and Building Sciences
Vellore Institute of Technology-UniversityVellore Institute of Technology-University
Vellore 632014Vellore 632014

2. DefinitionDefinition
A composite material is a multi-A composite material is a multi-
component system with at least a matrixcomponent system with at least a matrix
and a reinforcement.and a reinforcement.
The desired properties must be better thanThe desired properties must be better than
at least one of the constituents.at least one of the constituents.
The constituents are normally physicallyThe constituents are normally physically
separable , with a line of heterogeneityseparable , with a line of heterogeneity
between them, called the interface.between them, called the interface.

3. ContentsContents
ApplicationsApplications
MicromechanicsMicromechanics
Meso and MacromechanicsMeso and Macromechanics
Modelling and SimulationModelling and Simulation
Mechanical TestingMechanical Testing
Fracture, Failure Theories and DesignFracture, Failure Theories and Design
Design PhilosophyDesign Philosophy
SummarySummary

4. Composites in Wind EnergyComposites in Wind Energy
www.suzlon.com , www.ge.com
Vestas RRB

5. Composites in StorageComposites in Storage
Corrosion and weathering free thermoset and thermoplastic matrix
glass fibre reinforced composite storage tanks, pressure vessels and
containers are cheaper and more durable than conventional containers

6. Roads with Plastic WastesRoads with Plastic Wastes

7. Fuel from Plastic WastesFuel from Plastic Wastes

8. Biomedical CompositesBiomedical Composites
s
75X106
cyles of heart beat78 x 106
cycles of heart beat
over 25 years

9. Composites in DentistryComposites in Dentistry
Acrylics, Acrylic esters, Bis-
GMA, PMMA derivatives,
Ceramic filled composites
Can you make out the
difference ?
Ref: K. Padmanabhan , Programme overview, NIST ceramics machining
consortium, I th
Chapter, Gaithersburg, USA, October 8-9, 1998.

10. Composites in AutomobilesComposites in Automobiles
Italian automobile with carbon fibre composite chassis

11. All Composite EnginesAll Composite Engines
Aluminium Composite Engine
Composite Engine Manifold

12. All composite AircraftsAll composite Aircrafts
Indian Hansa-All composite aircraft
VTOL Aircraft
Ref: B.K. Parida, RMVGK Rao and K. Padmanabhan , Proceedings of the third joint
National Aerospace Laboratories- Chinese Aircraft Establishment workshop on
composites, April 22-24, Bangalore, India, 1996, p9. & NAL website

13. Composites - Sports & LeisureComposites - Sports & Leisure
Carbon fibre-nylon matrix – rigid foam
tennis racquet
Composite Yatch

14. Composites in DefenseComposites in Defense
A Bulletproof Vest A missile material case

15. Composites in SpaceComposites in Space
All aluminium alloy and carbon composites

16. Micromechanics is whereMicromechanics is where
design begins !design begins !
Design is defined
as the complete
information
required to
produce a
product
-
Anonymous

17. The Fibre-Resin Micro bondThe Fibre-Resin Micro bond
A drop of the cured resin on the
fibre surface showing adhesion
Fibre pullout test through a micro
vise design fixture

18. Micro bond Bundle Pull-out TestMicro bond Bundle Pull-out Test
Ref: K. Padmanabhan , Final project report to the Singapore –MIT Alliance ,
Singapore, November 2002

19. Interface TestsInterface Tests
Single fibre pullout testSingle fibre pullout test
Single fibre push out test, brittle materialsSingle fibre push out test, brittle materials
Micro bond single fibre pullout testMicro bond single fibre pullout test
Multiple fibre pullout test and Micro bondMultiple fibre pullout test and Micro bond
multiple fibre pullout test, Statisticallymultiple fibre pullout test, Statistically
averaged results, More precise, Lessaveraged results, More precise, Less
difficult, Mesomechanical in nature.difficult, Mesomechanical in nature.
Interlaminar shear strength test, ILSS.Interlaminar shear strength test, ILSS.

20. Multiple Fibre PulloutMultiple Fibre Pullout
Ref: K. Padmanabhan , Toyobo Confidentiality Report, 2002.
Ref: C. Y. Yue and K. Padmanabhan , Composites B, 30(1999) p205.
Micro bond Matrix slab

21. Modelling and AnalysisModelling and Analysis
Carbon Fibre and ZylonCarbon Fibre and Zylon™™ Fibre /epoxyFibre /epoxy
Matrix Embedded Composite SystemsMatrix Embedded Composite Systems
Cylindrical Assemblage
Model
Matrix
Pull Out Through a Micro vise
• Micromechanics
le

22. Interfacial ParametersInterfacial Parameters
Interfacial shear strength,Interfacial shear strength,ττ
Interfacial frictional stress, τInterfacial frictional stress, τff
Fibre/matrix coefficient of friction, µFibre/matrix coefficient of friction, µ
Matrix shrinkage pressure, PMatrix shrinkage pressure, Poo
Pressure due to Poisson expansion, pPressure due to Poisson expansion, paa
Contact pressureContact pressure
Interfacial wearInterfacial wear

23. Non-linear QuasistaticNon-linear Quasistatic
AnalysisAnalysis
Surface to surfaceSurface to surface
contactcontact
CAM is anisotropicCAM is anisotropic
and matrix is isotropicand matrix is isotropic
Only failure and postOnly failure and post
failure conditions werefailure conditions were
considered due toconsidered due to
relevance and precisionrelevance and precision
Model has dihedralModel has dihedral
symmetrysymmetry
Solid 8 noded brick 185 element
Hex swept volumes

24. Results of ANSYS AnalysisResults of ANSYS Analysis
37 MPa
Zylon/epoxy shear stress at CAM interface

25. FEM Analysis ResultsFEM Analysis Results
Carbon/epoxy shear stress at CAM interface

26. Micro buckling and DesignMicro buckling and Design
Micro buckling can beMicro buckling can be
prevented by choosingprevented by choosing
higher fibre diameter,higher fibre diameter,
higher fibre elastichigher fibre elastic
modulus and highmodulus and high
interfacial bond strengthinterfacial bond strength
between fibre and matrixbetween fibre and matrix
Boron fibres are the bestBoron fibres are the best
for design against microfor design against micro
bucklingbuckling

27. MacromechanicsMacromechanics
Transversely isotropicTransversely isotropic
composite needs 5composite needs 5
independent elasticindependent elastic
constants for efficientconstants for efficient
modelling (UD/0modelling (UD/000
))
Layered orthotropicLayered orthotropic
composite needs 9composite needs 9
independent elasticindependent elastic
constants for efficientconstants for efficient
modellingmodelling

28. 3 D Braided Structures3 D Braided Structures
3 D braided ,knitted, stitched and
fibre preform structures have
enabled easy manufacturing of net
shape FRPs. The modelling and
performance analysis of such
structures poses challenges

29. Failures and Multiple CausesFailures and Multiple Causes
In nature, most of the real environment failuresIn nature, most of the real environment failures
are due to multiple causes.are due to multiple causes.
As enough standard procedures are availableAs enough standard procedures are available
for failures due to a single cause, the obviousfor failures due to a single cause, the obvious
move is to develop the understanding as well asmove is to develop the understanding as well as
standard procedures for failures due to multiplestandard procedures for failures due to multiple
causes.causes.
An understanding of these failures leads to aAn understanding of these failures leads to a
better fracture control that aids superior designsbetter fracture control that aids superior designs
with advanced composite materialswith advanced composite materials

30. Mechanical TestingMechanical Testing
Ref: K. Padmanabhan and Kishore , ` Failure behaviour of carbon/epoxy
composites in pin ended buckling and bending tests’, Composites, Vol:26,
No: 3, 1995, p201.

31. Bolted and Bonded CompositeBolted and Bonded Composite
JointsJoints
Joint testing of a composite lug

32. Fracture Mechanics TestingFracture Mechanics Testing
Mixed mode testing of composite
materials is a recent trend as
causes are multiple during failure in
real conditions
Fracture mechanics tests to
evaluate fracture toughness
and strain energy release
rates have found quite a few
standards in ASTM

33. Composites in MicroelectronicComposites in Microelectronic
PackagingPackaging
The BOM includes Copper lead frame,
Gold wires for bonding, Silver –epoxy
for die attach, Silicon die and Epoxy
mould composite with Phenolics, Fused
silica powder and Carbon black powder
as the encapsulant materials.

34. Thermal – Structural ResultsThermal – Structural Results
Displacement Vector sum Von mises stress
Stress intensity XY Shear stress

35. Non Destructive EvaluationNon Destructive Evaluation
Ultrasonic C-Scan NDT
can do depth profiling of
composites delamination
and damage profiling
Scanning acoustic microscope
can sense delaminations of
micron dimensions ( shown as
red areas) in TQLMP IC
packages. FEA techniques are
also NDE techniques.

36. Composites in ProsthodonticsComposites in Prosthodontics
Tooth is a functionally graded
composite material with enamel
and dentin. In the third maxillary
molar the occlusal stress can
be 2-3 MPa.
The masticatory heavy chewing
stress will be around 193 MPa.
A composite restorative must with
stand this with an FOS and with
constant hygrothermal attack.

37. Hygrothermal BehaviourHygrothermal Behaviour
Fibre reinforced plastics are known forFibre reinforced plastics are known for
environmental attacks that reduce their function.environmental attacks that reduce their function.
Mechanical properties degrade over time !Mechanical properties degrade over time !
Moisture plays havoc at elevated temperatures,Moisture plays havoc at elevated temperatures,
in the presence of voids, defects and in low Tin the presence of voids, defects and in low Tgg
plastics .plastics .
Diffusion and osmotic pressure are the drivingDiffusion and osmotic pressure are the driving
mechanisms for hygrothermal attackmechanisms for hygrothermal attack
Evaluation methods and surface preservationEvaluation methods and surface preservation
Important in marine, biomedical, aeronautical,Important in marine, biomedical, aeronautical,
electronic and automobile applicationselectronic and automobile applications

38. Azzi-Tsai-Hill Failure TheoryAzzi-Tsai-Hill Failure Theory
Where,
σ11 = X ( tensile / compressive) stress in MPa
σ22 = Y ( tensile / compressive) stress in MPa
τ12 = Shear stress in MPa
SLt = Longitudinal tensile strength in MPa
STt = Transverse tensile strength in MPa
SLts = In-plane shear strength in MPa

39. Tsai – Wu Failure TheoryTsai – Wu Failure Theory
F1 σ11 + F2 σ22 + F6 τ12+ F11 σ11
2
+ F22 σ22
2
+ F66 τ12
2
+2 F12 σ11σ22 = 1
Where,
Other parameters / symbols appear on the previous slide,
SLc = Longitudinal compressive strength in MPa
STc = Transverse compressive strength in MPa.

40. ASTM STP D 5229 M RuleASTM STP D 5229 M Rule
The MOT( Maximum Operating Temperature)The MOT( Maximum Operating Temperature)
of the material, device/component should beof the material, device/component should be
at leastat least 25 º Celsius lower than the lowest Tg
(normally wet) of the material attained after
hygrothermal equillibration. All the polymeric. All the polymeric
materials and their composites must satisfymaterials and their composites must satisfy
this rule in order to qualify for certification forthis rule in order to qualify for certification for
reliability and durability.reliability and durability.

41. Sandwich Core MaterialsSandwich Core Materials
Foam
Honey
comb

42. Sandwich Showing Core andSandwich Showing Core and
Skin –Core Interfacial FailureSkin –Core Interfacial Failure
Tensile faceCore failure
Ref: ASTM C 393/C393M-06, ASTM D7249/ D 7249 M-06, ASTM D7250/
D7250M-06

43. Advances in SandwichAdvances in Sandwich
CompositesComposites
•Develop fracture mechanics test
methods for sandwich
composites
•Focus on facesheet core delamination
•Both Mode I and Mode II
Suitable for ASTM standardization
Ref: Dan Adams, Department of Mechanical Engg ,
Department of Mechanical Engineering
University of Utah, Salt Lake City, UT, USA

44. Design OptimizationDesign Optimization
Ref: 1. G.R. Froud ,Composites, July, 1980, p 133
2. RMVGK Rao et al in Jl. Of Reinforced Plastics and Composites,
Vol:25, No: 6, 2006, p 663

45. Design Optimization for StrengthDesign Optimization for Strength
Glass-Epoxy Skin Showing
Buckling Delamination Type
Of Failure on the Compressive
Face.
Carbon-Epoxy Skin Showing
Buckling Delamination Type
Of Failure on the Compressive
Face.
Skin Weight= Core Weight

46. Zylon FibreZylon Fibre
www.toyobo.co.jpwww.toyobo.co.jp
ZYLON consists of rigid-rod chain molecules of poly(p-
phenylene-2,6-benzobisoxazole)(PBO).
Tensile Strength : 5.8 GPa
Tensile Modulus : 270 GPa
Ref: K. Padmanabhan , Toyobo Confidentiality Report, 2002.

47. NanocompositesNanocomposites
The SWNT has a Tensile Modulus of 1-5 TPa and a Tensile Strength of 13-53
GPa at an elongation of 16 %. A 0. 50 Vf composite , in theory will have a tensile
strength and a modulus around half as much, assuming that the matrix is weak !
Carbon nanotubes

48. Design Philosophy- DesignDesign Philosophy- Design
PropertiesProperties
Strength, Stiffness, Toughness, Fatigue, Creep,Strength, Stiffness, Toughness, Fatigue, Creep,
Impact and Damage toleranceImpact and Damage tolerance
Dimensions, Weight, TolerancesDimensions, Weight, Tolerances
Judicious use of drafts, radii, fillets, webs, ribs,Judicious use of drafts, radii, fillets, webs, ribs,
blends, chamfers and curves for specificblends, chamfers and curves for specific
propertiesproperties
Ease of assembly, disassembly and serviceEase of assembly, disassembly and service
Aesthetics, colouring and texturing, Eco friendlyAesthetics, colouring and texturing, Eco friendly
designdesign

49. Design Philosophy-Design Philosophy-
Manufacturing PropertiesManufacturing Properties
Forming temperature, Glass transition, MeltingForming temperature, Glass transition, Melting
point, Rate of solidificationpoint, Rate of solidification
Energy required to form, Whether batch processEnergy required to form, Whether batch process
possible? , Pressure requiredpossible? , Pressure required
Flow behaviour, Viscosity, Melt flow indexFlow behaviour, Viscosity, Melt flow index
Mouldability and Castability, WorkabilityMouldability and Castability, Workability
Fabrication of Complex Parts, TimeFabrication of Complex Parts, Time
Curing/Solidification Shrinkage in the MouldCuring/Solidification Shrinkage in the Mould
Materials properties, Availability, Toxicity, SafetyMaterials properties, Availability, Toxicity, Safety

50. Design Philosophy-Design Philosophy-
Customer RequirementsCustomer Requirements
Quality, Cost, Durability ( low moistureQuality, Cost, Durability ( low moisture
absorption), Reliability ( low degradation ofabsorption), Reliability ( low degradation of
properties with time)properties with time)
Efficiency : Better properties at lighterEfficiency : Better properties at lighter
weight and less money, Valueweight and less money, Value
Flexibility : Multi functionalityFlexibility : Multi functionality
Low maintenance costLow maintenance cost
Aesthetics, textures in DesignAesthetics, textures in Design

51. Design PhilosophyDesign Philosophy
Pyramidal SubstantiationPyramidal Substantiation
The aircraft ,we hope,
is never tested
The sub-assemblies and the
assemblies
are tested the least
The subcomponents and components
are tested less often
The test specimens are tested more often

52. BibliographyBibliography
P,K. Mallick, Fibre reinforced composites, Marcel andP,K. Mallick, Fibre reinforced composites, Marcel and
Dekker Inc., New York .Dekker Inc., New York .
Derek Hull and T.W. Clyne, ` An Introduction toDerek Hull and T.W. Clyne, ` An Introduction to
composite materials’, Cambridge solid state sciencecomposite materials’, Cambridge solid state science
series, 1996.series, 1996.
E.J. Barbero, `Introduction to composite materialsE.J. Barbero, `Introduction to composite materials
design’, Taylor and Francis ,MI.design’, Taylor and Francis ,MI.
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reinforced composites ‘, Elsevier, 1998.reinforced composites ‘, Elsevier, 1998.
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Rao Tummala, Microsystems Packaging,McgrawHill.Rao Tummala, Microsystems Packaging,McgrawHill.

53. BibliographyBibliography
Sanjay K Mazumdar, Composites Manufacturing, CRCSanjay K Mazumdar, Composites Manufacturing, CRC
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ASTM Standards Handbooks Vols: 08.01,08.02 andASTM Standards Handbooks Vols: 08.01,08.02 and
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www.astm.orgwww.astm.org
ANSYS v.11 Analysis Manuals, 2008.ANSYS v.11 Analysis Manuals, 2008.
Rayner M Mayer, Design with Reinforced Plastics,Rayner M Mayer, Design with Reinforced Plastics,
Design Council, London.Design Council, London.

54. BibliographyBibliography
K. Padmanabhan, S.Subeesh, K. Balaguru and T.K. Padmanabhan, S.Subeesh, K. Balaguru and T.
Karthik , ` 3D Modelling and Failure Analyses of ICKarthik , ` 3D Modelling and Failure Analyses of IC
packages’, in ANSYS Users’ Conference CD, 6 & 7packages’, in ANSYS Users’ Conference CD, 6 & 7
November 2008, Bangalore.November 2008, Bangalore.
K. Padmanabhan, S.Subeesh, K. Balaguru and T.K. Padmanabhan, S.Subeesh, K. Balaguru and T.
Karthik , ` An Analyses of Reliability andKarthik , ` An Analyses of Reliability and
Hygrothermal Effects in IC packages’, in ANSYSHygrothermal Effects in IC packages’, in ANSYS
Users’ Conference CD, 6 & 7 November 2008,Users’ Conference CD, 6 & 7 November 2008,
Bangalore.Bangalore. BEST PAPER AWARDBEST PAPER AWARD
K. Padmanabhan, D. Sanjay and S Subeesh,` DesignK. Padmanabhan, D. Sanjay and S Subeesh,` Design
and electro-hygrothermo-mechanical reliabilityand electro-hygrothermo-mechanical reliability
analyses of a leadless quad IC package’, in theanalyses of a leadless quad IC package’, in the

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ொமைய்ப்பொபொருள் கொண்பது அறிவொமைய்ப்பொபொருள் கொண்பது அறிவ..
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