FEM-ME4063 Course Introduction

ME 6093 Mechanics of CompositesFall 2015Offered By: Dr Rizwan Saeed Choudhry

1Department of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad CampusDr Rizwan Saeed ChoudhryBE (NUST, Pakistan - 2002) MS (NUST, Pakistan - 2003)MS (The Uni. of Manchester, UK - 2004), PhD (The Uni. of Manchester, UK - 2009)Post Doc (Manchester (2009) Post Doc Cambridge , UK (2013) Assistant Professor (NUST Dec 2009 to 2015)Current role: Associate Professor

2Web: www.cemecomposites.com Email: rizwan.choudhry@gmail.comrizwan.saeed@jinnah.edu.pk Profile: LinkedInProfGradIMMM IOM, UK Professional Engineer P.Eng. PEC, Pak

Department of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus

NATIONAL UNIVERSITY OF SCIENCES & TECHNOLOGYThe logos on this slide represent the places where I have studied, worked or both2About the CourseCourse Learning OutcomesTo understand the different types of composite materials and their current and future applications in engineering.To understand the effect of choice of processing route / manufacturing strategy on mechanical properties of compositesTo design and analyze structures made of composites (mechanics of composites). To familiarize students with advanced concepts of computer aided modeling and simulation of failure and damage in composites (FRC). To develop an understanding of differences of testing standards for mechanical testing of composites as opposed to those of traditional materials.3Department of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad CampusBooks and ReferencesMain Text books:Introduction to Composite Materials Design, 2nd Edition (2011) Ever J Barbero An introduction to Composite Materials, 2nd edition By D. Hull & T. W. ClyneSpecial TopicsEngineering Mechanics of Composites Materials 2nd edition Isaac M Daniel, Ori IshaiMaterial selection in mechanical design, 4th edition, by M. F. AshbyPrinciples of Composite Material Mechanics, 2nd Edition by Ronald F. GibsonAll other sources consulted will be referred to in slidesA note about slides: The slides for lectures have been prepared using various sources. For the lectures in first six weeks most of the slides are modified versions of Lecture slides used by Professor Paul J Hogg at University of Manchester for the course Composites Science and Engineering4Department of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad CampusLesson PlanIntroduction to Composites (constituent materials, forms and properties)Week 1,2Related reading: Chapter 2 Barbero, Chapter 1,2,3 Clyne + Lecture SlidesManufacturing techniques for composites and process selection methodologyWeek 3,4Related reading: Chapter 3 Barbero, Chapter 11 Clyne, + relevant portions of chapter 5, 6 and 14 Ashby + Lecture SlidesDesign for composites key considerationsWeek 5Related reading: Chapter 1 Barbero, Chapter 1,2,3 Clyne + Lecture SlidesStructure property relationship and micromechanics of composites Week 6,7,8Related reading: Chapter 4 Barbero, Chapter 4,5 Clyne + Lecture Slides5Department of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus5Lesson PlanLinear elastic stress analysis of composite structures (Macro-mechanics, ply-mechanics)Week 9,10,11Related reading: Chapter 5,6 Barbero, Chapter 5 Clyne + Lecture SlidesMechanics of Short/discontinuous fiber reinforced composites (optional topic if time permits)Week 12Related reading: Chapter 6 Gibson + Chapter 6 Clyne + Lecture SlidesMechanical testing of composites and testing standardsWeek 13,14Related reading: Chapter 10 Daniel and Ishai + Lecture SlidesFailure theories for composites laminates and progressive damage modelling Week 15,16Related reading: Chapter 7,8 Barbero, Chapter 8,9 Clyne + Lecture SlidesIntroduction to FE analysis of composites using ABAQUS (Optional topic if time permits)6Department of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus6StructureCredit Hours: 3-0Contact Hours: 3-0Final Exam: 40 - 50 % Midterm: 20 - 30%Quizzes:10%Assignments/Project:20%

7Department of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad CampusComposite Materials - BasicsComposites are a heterogeneous combination of two or more materials usually having distinct properties which remain distinct even after forming the composite.The performance and properties of the combination are designed to be superior to those of constituents acting independently. Adhesive or Mechanical bonding between the constituentsFiller material reinforces a weak matrix Matrix low density ; Filler strong, stiffTraditional examples : Wood, Bricks, ConcreteAdvanced composite examples: Fibre reinforced plastics (FRP) Carbon, Glass, Kevlar, Natural fibre reinforced compositesDepartment of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus9Introduction What are composites?

Dictionary definition:A composite refers to something made up of various parts and elementsThe different constituents must have two prime characteristicsChemically differentInsoluble in each other.In almost all cases, there is aStrong and stiff component forming the reinforcementSoft constituent that binds the reinforcementStructural composites typically refer to the Macrostructural level:e.g. matrix, particles, fibres9Types of compositesClassification on basis of matrixPolymeric matrix compositesMetal Matrix compositesCeramics matrix compositesDepartment of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus11Classification of compositesThe first level of classification of composites is by matrix typeThe major composite classes arePolymer Matrix Composites (PMCs)Use a polymer-based material as the matrix, and a variety of fibres such as glass, carbon and aramid as the reinforcementPMCs are used in the greatest diversity of composite applications, as well as in the largest quantitiesThey can be further classified into small groups according to the Fibre e.g. glass, carbon or aramid compositesMatrix e.g. thermosetting, thermoplastic or rubber compositesThey can also be categorised into short-fibre reinforced composites, or continuous-fibre reinforced compositesAlso known as FRP - Fibre Reinforced Polymers (or Plastics) As these are the most common they will be the main focus of the courseDepartment of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus1112Classification of composites (cont)Metal Matrix Composites (MMCs) Use a ductile metal such as aluminium for the matrixReinforced with fibres or particles of alumina, boron, silicon carbideIncreasingly found in the automotive industryCeramic Matrix Composites (CMCs) Use a ceramic as the matrix and reinforce it with short fibres or whiskers such as those made from silicon carbide and boron nitrideUsed in very high temperature environmentsDepartment of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus12Types of compositesClassification on basis of reinforcementsContinuous fibre strands or roving Chopped strands in short lengthChopped strand matChopped strand aligned matFibre RovingWoven Fabrics 2D and 3D made from roving or strandsMetal filament or wiresSolid or hollow microspheresMetal, glass or mica flakesSingle crystal whiskers of graphite, silicon carbide, copper etc.Nano-particle and nano-fiber reinforcements

Robotic fibre placement at NCCEF, UKDepartment of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus14Classification of composites (cont)The second level of classification is by reinforcement formFibre reinforcementFibre is characterised by a high aspect ratio, i.e. the length of the fibre is much greater than its diameterFibres can be Short i.e. where properties of composite vary with fibre lengthLong or continuous, i.e. further increase in fibre length has no effect on the composite properties. Long fibres typically have lengths comparable to that of the final part. Long fibres are manufactured into preforms for ease of manufacturingThese are the most common and will be discussed in detail later onDepartment of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus1415Classification of composites (cont) Whisker reinforcement Characterised by aspect ratios of approximately 20-100 Particulate reinforcementDimensions of particles are roughly equal. This category includesSpheres, rods, flakes etc.Mostly tend to be included for cost reduction purposes and are non-structuralTo provide a useful increase in properties, the reinforcement has to be included at a sufficient volume fraction (typically >10%)Particulate and whisker reinforcements are classified as discontinuous reinforcements. This is especially so for MMCs where the volume fractions of particles is quite low

1516History of Composites1940sPMCs used to produce materials with stiffnesses and strengths that were higher than for the existing materialsFilament wound GRP rocket motors Prototypes for aircraft applicationsStructural alloys susceptible to corrosion and creep damage

Gordon Aerolite SpitfireFuselage from flax-fibre compositeNo property advantages & weight same as aluminium fuselageAl shortage never materialised, concept dropped1617History of Composites1950sImproved structural response and corrosion resistance of PMCsInitial development of MMCsIdea was to dramatically extend the structural efficiency of metallic materials while retaining their advantages1960sCommercial applications for PMCs in sporting equipmentImproved design and production capabilities, and PMCs lower in costsDevelopment of Boron and SiC monofilamentsDepartment of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus17History of Composites1970s Cold war budgets allowed for significant research in high-performance materialsMilitary aircraft built with composite sections (tailskins & noncritical flight structures)Energy crisis provided incentive for introduction of PMCs into the manufacture of commercial aircraftDevelopment of carbon fibresHigh cost of SiC whiskers led to development of particulate reinforcements for MMCsNearly equivalent strengths & stiffness as whiskersReduced costs, eased processing18

MMC piston head linerDepartment of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus18History of Composites1980s Development of monofilament reinforced Ti MMCsDesigned for high temperature aeronautical systems: blades for gas turbine enginesIncreased use of composites in military and commercial aircraftCommercial aircraft use composites for critical load-bearing applications Development of fibreglass structures for boats and marine applications19

Department of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus1920Starship Bizjet - >75% of structural weight was composite.Global Market had grown from about 1000 tonnes in 1980 to 5000 tonnes of fibres in 1985 and almost 10,000 tonnes by 1989

AV8B Harrier all composite wing for improved payload /range27% of structural weight is compositeAirbus A320 all composite tail, up to 15% of structural weight is composite

Major applications of PMCs in the 80sSAAB Grippen Wing all composite20AV8B Harrier McDonald Douglas and Later joined by British AerospaceSaab Grippen Sweedish 21

Specialist aircraft such as the B-2 stealth bomber mainly composite due to low radar absorbance and ability to manufacture suitable shapes. 40% by weight (60% by volume) compositeStealth bomber2122

New tough composites used for bigger composite wings on F-18E/F range up to 22% composite.Re-vamping earlier aircraft22History of Composites1990s Development of MMCs for ground transportation, thermal management & electronic packagingThis market is significantly larger than the aerospace marketHowever market volumes are still very smallWorld market in 1999 was 2500tons62% for groundtransportation(automotive and rail)

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Department of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus2324History of Composites2000s Modern aircraft designed to use large quantities of carbon fibreA380 (eta. 2006)Combines Al & GRP as a multilayer material (GLARE)25% weight saving & less susceptible to fatigue than Al40% CFRP for wingbox = 1.5t weight saving16% by weight total composites787 Dreamliner (eta. 2007)50% structural weight composites = 25t of CFRP per aircraftKey driving factors are reductions in the cost to manufacture quality parts17% fuel reduction over current generationDemand outstripping supply

Department of Mechanical EngineeringMohammad Ali Jinnah UniversityIslamabad Campus2425A380

2526Commercial aerospace use

2627Military aerospace use

Development of composite military aerospace applications

2728

Where do we find composites now?

Glass Fibre2829

Where do we find composites now?

Carbon Fibre2930

Where do we find composites now?

MMCs & CMCs

3031Composites driving forcesCriteria on which composites are selected depend on the industry in which they will be used Aerospace: mainly weight reduction with increased stiffness/strengthHigh scrap levels are (were?) toleratedThere is a preference for high performance materials in order to reach the weight savingsFibres need to be continuous and volume fractions need to be highTransportation: Emphasis is on decreasing costReturn on investment, complex shapes, recycling, etc.Need to reduce weight as increased safety requirements = heavier vehicles = worse fuel economyManufacturing routes need to be low-cost and high speed: fibre volume fractions not so much of an issueAerospace:Strength, stiffness,weight, quality controlMechanical Industry:Design, strength, qualityAutomotive:Automated fabricationPerformance1/CostRate of Production32Why composites?Monolithic materials contain numerous flaws and cracksThis causes them to fail below their theoretical breaking point as the propagation of the flaw causes failure of the materialFibre form still contains the same number of random flawsHowever they are restricted to a small number of fibres with the remainder exhibiting the materials theoretical strengthIf a flaw causes failure within a fibre, it will not propagate to fail the entire assemblage of fibresThe fibres therefore more accurately reflect the optimum performance of the material

32Why composites?33Fibres alone can only exhibit tensile properties along the fibres length similar to fibres in a ropeNeed resin to bind them togetherComposites can be engineered for high strengths and stiffnessesease of moulding complex shapeshigh environmental resistance low densities, etc.

The resultant material is superior to metals for many applications!33

34The benefits of composite materials are traditionally based on the following:Corrosion resistanceLightweightHigh strengthHigh stiffness

MSc Composites Science & Engineering3435Multifunctional materials: Structure of wood

Wood is a natural compositeRequirements:It has to be tall and straightIt must be strong and light and resist bending forcesControlled heat dissipationControlled moisture retention ... Etc.It is composed of multiple fibre bundles (lamellae) each of which contains multiple layers of cellulose fibres in a lignin matrixLamellae are aligned on the long axis of the woodSuperior bending and longitudinal stiffnessAlignment of cellulose fibres within lamellae indicates stiffness & strength of the woodMSc Composites Science & Engineering3536Anisotropy of wood

Effects of Anisotropy:Material has high stiffness and strength along fibres, but cracks can also easily propagate along itCracks very difficult to propagate across the fibresMSc Composites Science & Engineering3637Wood composites

Plywood:Thin sheets of veneer that are cross-laminated and glued together with a hot-pressGrain of each layer is positioned in a perpendicular direction to the adjacent layer Odd number of layers so that the panel is balanced around its central axis Bamboo:Layered natural wood composite

MSc Composites Science & Engineering3738Structure of bone

Bone:Compact/cortical bone is the structural part of bones Consists of multiple osteons within a matrix of old osteonsOsteons are aligned in the direction of applied load Structurally, each osteon is composed of multiple lamellae in a plywood type arrangement (compact bone is known as lamellar bone in adults)Within each osteons are hydroxyapatite whiskers in a collagen matrix

Outer lamellaeInner lamellaeOsteonsMSc Composites Science & Engineering3839Engineered materialsFibres provide strength and stiffness Resin acts as a binder and spreads the load applied to the composite between each of the individual fibres and protects the fibres from damagecontrols the transverse propertiesTensile StrainTensile StressFibreCompositeResinThe combination of resin and reinforcing fibres produces a composite whose properties are a combination of the properties of each of the constituents Overall, the properties of the composite are determined by the: Properties of the fibre (provide stiffness & strength)Properties of the resin Ratio of fibre to resin (Fibre Volume Fraction) The geometry and orientation of the fibresMSc Composites Science & Engineering3940E-glass: Most common glass fibreUseful balance of mechanical, chemical & electrical properties

ReinforcementsGlass fibresOriginal structural reinforcement & most commonCompetitively priced & widely availableEase of processing & good handleability.Carbon fibresBest known & most widely used high performance fibreWide range of mechanical propertiesLinear stress-strain behaviourStrength3.45 GPaStiffness75.8 GPaDensity2.56 g/cm3Diameter8-15 mmCost~70-150 /kgTypical properties of carbon fibres

Strength3.5-6.4 GPaStiffness240-310 GPaDensity~1.85 g/cm3Diameter5-10 mmCost~1000-3000 /kg

MSc Composites Science & Engineering4041Kevlar-49: Most common aramid reinforcement fibre

ReinforcementsAramid fibresOrganic fibreHigh tensile stiffness & strengthLow stiffness = ballistic gradeHigh stiffness = reinforcement grade Very poor compressive properties (similar to that of glass fibres)Most commonly known as KevlarSiC & AluminaUsed in MMCs and CMCsGood thermal stabilityBoron fibresMonofilament wiresExcellent strength and stiffnessMore expensive than carbon fibresUsed in PMCs and MMCsHigh performance thermoplasticsHighly drawn UHMWPENatural fibresDerived from plants, i.e. eco-friendlyStrength3.45 GPaStiffness180 GPaDensity~1.4 g/cm3Diameter~12 mmCost~1000-2000 /kg

MSc Composites Science & Engineering4142Comparison of (UD) composite properties

Unidirectional (UD) Carbon properties are the highest of all common compositesAramid fibres have excellent tensile properties but weak compressive propertiesS-Glass (high strength glass fibres) approach the tensile stiffness of aramids, strengths of HS Carbon in addition to very high failure strainsE-Glass is a general all-rounder that possesses high failure strainsMSc Composites Science & Engineering4243Woven fabric - yarnUD fabric - rovingComparative fibre costs

MSc Composites Science & Engineering4344Typical properties of unsaturated polyesters

Matrices thermosetting resinsPolyester resinsMost commonly used resins & wide range of formulations, curing agents, etc.Acceptable mechanical properties & acceptable environmental durabilityVery good adhesion to glass fibreHigh styrene emissions & high shrinkage on cureVinyl ester resinsSimilar processing to polyestersVery high chemical and environmental resistanceBetter overall properties to polyestersHigher cost

Strength55-90 MPaStiffness3.4-4.4 GPaStrain to failure1.6-4.5 %Density1.1-1.5 g/cm3Cost~70-150 /kgTypical properties of vinyl esters

Strength60-93 MPaStiffness2.9-3.9 GPaStrain to failure3.0-16 %Density1.0-1.3 g/cm3Cost~150-300 /kgMSc Composites Science & Engineering4445Typical properties of epoxies

Matrices thermosetting resinsEpoxy resinsMost used resin for advanced compositesVery good mechanical and thermal propertiesGood water resistanceLow shrinkage on cureNeeds proper mixing formulationExpensive PhenolicsHigh fire resistance & excellent thermal propertiesCure by condensation reaction resulting in voidy laminateCyanate estersSuperb electrical properties & low moisture absorbanceUsed in radomes, antennas, etcVery expensive (~3000 /kg)Bismalemides (BMI)Superior to epoxies for hot/wet use & suitable for high operational temps.>3500 /kgPolyimidesHigher operational temps. than BMICures similar to phenolicsExtremely expensive (>5500 /kg)Strength55-130 MPaStiffness2.5-6.0 GPaStrain to failure3.1-15 %Density1.1-1.4 g/cm3Cost~200-1000 /kgMSc Composites Science & Engineering4546Matrices thermoplastic resinsThermoplastic resinsOfferIncreased toughness Higher strain to failure than thermosetsImproved impact resistanceImproved hot/wet resistance:They do not absorb any significant amount of water but are subject to chemical attackIndefinite shelf lifeCan be molten and moulded as neededProblemOperational temperature must be below the Tg Subject to creep at high temperaturesEngineering thermoplasticsPA (Polyamide)Self-lubricating & exhibit good abrasion resistanceGood chemical resistance but high water absorption PP (Polypropylene)Low density & low costHigh impact propertiesPET (Polyester terephtalate)Comparable processing to PPHigher service temperature &Stiffer than PPPEEK (Polyether ether ketone)Highest performing engineering thermoplasticHigh cost & cost of processingMSc Composites Science & Engineering4647Matrices otherMetal matricesAluminiumMost common reinforced metalTypically used as a pre-mixed casting alloy but wrought alloy can be used for infiltration castingTitaniumTypically used with continuous reinforcement due to difficulty with processing titaniumOthersOther metals, e.g. Cu, Be, Ag, used to retain their excellent thermal and electrical properties and improve their thermal expansion/ wear resistanceCeramic matricesUse of ceramic matrix is to improve poor toughness characteristics of these matricesVery few applications exist, most common being Carbon/Carbon brakes.

MSc Composites Science & Engineering4748Engineered materials

Consider the properties of the individual constituents:The mechanical properties of the fibres are superior to monolithic materials especially as they are light weight.The mechanical properties of the resins are worse than most engineering materialsThe mechanical properties of the composite depends on the placement of the reinforcementComposites possess superior specific stiffness and strength than steel.However this mostly occurs when properties are measured in the direction of the fibres.Specific property = property / densityMSc Composites Science & Engineering4849Engineered materialsMetals:Properties are largely determined by material supplier;End-processors can do little to change those 'in-built' propertiesComposite material:Often formed at the same time as the end-product is being fabricated ;This means that the person who makes the end-product creates the properties of the material in use Because of the large variation in material parameters including fibre strength, stiffness, volume fraction, length and orientation it is possible to engineer or design the required properties and the direction in which they are required.StrainStressCompositeCompositeMetals &AlloysMSc Composites Science & Engineering4950Controlling Anisotropy

There are three levels of orientationRandom (quasi-isotropic properties)Cross-ply (transversely isotropic)Unidirectional (orthotropic)Effects of anisotropyAligning fibres in direction of load (i.e. producing unidirectional composite) produces the highest propertiesPerpendicular load carrying capacity becomes rather poorCan be relieved by placing fibres in transverse direction, but lowers effective propertiesMSc Composites Science & Engineering5051

Benefits from anisotropyOrienting the reinforcements in the direction of the applied loads has a significant effect on the properties of the final compositeProperties are roughly equal to the stiffness volume fraction of the fibresIn unidirectional orientation, there are more fibres in the loading direction than in the random orientation MSc Composites Science & Engineering5152Effect of aligning fibres

For random orientations, improvement of properties over metallic materials is not that significant.Need to use CFRP which equates to higher costsMSc Composites Science & Engineering5253StrengthsWeight reduction High specific stiffness & strengthLow maintenance cost Corrosion resistanceDesign flexibility & integrated partsLarge, complex structures can be created in one piecePigmentation and textures can be incorporated directly into the composite at the manufacturing stageEnvironmentally friendlyLow energy consumption in manufacture.SafetyCrush structuresDurabilityCarbon fibre reinforced plastics possess excellent fatigue propertiesGlass fibre reinforced plastics are excellent electrical insulatorsMSc Composites Science & Engineering5354

StiffnessStrengthProperties will vary with fibre contents and orientations. Lowest property for short & random fibre composites, and highest for UD fibre prepregs.

traditionalmaterialscompositematerialsComparison with other materials: Stiffness & StrengthMSc Composites Science & Engineering5455

Density: Composite materials have a very low density compared to metals and are therefore of interest for light-weight designComparison with other materials: DensityMSc Composites Science & Engineering5556

Specific strengthSpecific stiffnessComparison with other materials: Specific PropertiesMSc Composites Science & Engineering5657Why composites? Integrated parts

MSc Composites Science & Engineering5758Safety

Displacement (mm)Load (kN)Initial Peak LoadAverage Crush LoadRegion ofsustained crush Load FluctuationAmplitude

Composites absorb more energy per kilo than metals in a crashCrushing pattern is stable unlike that of metals that fail by bucklingComposites exploited in Formula 1 (since 1982) and trains

MSc Composites Science & Engineering5859

MSc Composites Science & Engineering5960Composite weaknessesCosts of processing still highMost processing methods require a huge investment in manual labour and/or machineryAbsence of mass production technology for high-performance compositesTypical routes are pre-preg which is performed either by manual layup or by tape layupRecycling of thermosets impracticalOnly real route apart from regrinding as filler is pyrolysisRecycling of thermoplastics with glass fibres difficultOption is to regrind long-fibre composites as lower grades for injection mouldingLack of knowledge in designing with anisotropic materialsMSc Composites Science & Engineering6061Composite weaknesses (cont)Uncertainty regarding long-term propertiesFactors such as moisture degradation, damage tolerance after impact requires large safety margins in designUncertainties in predicting failure modesCrack propagation mechanisms, damage tolerance after impact delamination etcAircraft industry works on a zero crack tolerance approach (structures are therefore over designed)Inadequate industrial capacity (world annual production of carbon only about 30,000 tonnes/annum)The use of just 20% structural weight of carbon in the Airbus A380 is consuming all excess productionMSc Composites Science & Engineering6162

?Performance versus ProductionIdeal situation for composite takeup would be to have high modulus parts capable of being produced at over 1000 parts per dayMSc Composites Science & Engineering6263Factors favourable for metal substitutionThe gain achieved in using composites to achieve these objectives is greater than the costs associated with using compositesComposites are seldom used for just one benefitIt is usual that a combination of properties is required before they are used to substitute for alternative materials. Most successful composite designs are NOT direct shape replacements for an existing metal component. Design should incorporate aspects of the compositeFeatures such as anisotropy and mouldability should be used to achieve a cost effective product. MSc Composites Science & Engineering6364Prepreg (autoclave) prepregs were expensiveCapital equipment (Autoclaves, tape layers) are expensive, material deposition rates and processing are slowMore than 70% of part cost from fabrication!

Inefficient manufacturing processesMSc Composites Science & Engineering6465

CostsCar