Seminar onManufacturing of composite

material

under guidance of-Prof. Dr. I. Basak

Raghvendra Kumar Pandey10/ME/123

NIT Durgapur

Composite materials:-

▪ A microscopic mixture of two or more different materials. One typically being the continuous phase (matrix), and the other being the discontinuous phase (reinforcement).

▪ Its properties are strongly dependent on the composite structure.

Apr 10, 2023 2Ceramic fiber composite Polymer matrix composite

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Why Composites?

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▪ Composites can be very strong and stiff, yet very light in weight, so ratios of strength-to-weight and stiffness-to-weight are several times greater than steel or aluminium.

▪ Reduces maintenance costs

▪ Reduces or eliminates corrosion

▪ Better fatigue resistance

▪ Less thermal expansion

▪ Enhanced properties via tailor able properties

– Mechanical

- Electrical

▪ Reduces cost Boeing 787 Composite Usage

Composite Aluminium TitaniumSteel Other

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Fiber

particle

Flakes Laminar

Filled composites

Types of composites:-

classificationMMCs

Metal matrix composites

• Ceramics + metals• For example cemented carbides and other cermet's• Aluminium or magnesium reinforced by strong, high stiffness fibers

CMCsCeramic Matrix

Composites

• A ceramic primary phase imbedded with a secondary phase, which usually consists of fibers

• Least common composite matrix• Aluminium oxide and silicon carbide are materials that can be

imbedded with fibers for improved properties, especially in high temperature applications

PMCsPolymer Matrix

Composites

• Thermosetting resins are the most widely used polymers in PMCs.• Epoxy and polyester are commonly mixed with fiber reinforcement

composite

primaryForms the matrix within which the secondary phase is imbedded

Any of three basic material types: polymers, metals, or ceramics

Secondary Referred to as the imbedded phase or called the reinforcing agent

Can be one of the three basic materials or an element such as

carbon or boron

Serves to strengthen the composite

Matrix material function:-

A. Provides the bulk form of the part or productB. Holds the imbedded phase in placeC. Shares the load with the secondary phaseD. Polymer e.g. PEEK, Polyester, polyurethane, RubberE. Metal e.g. Al, Cu, Ti, NiF. Ceramic e.g. cements, glass.

Reinforcement:-1. Rovings

continuousbulk

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Continuous strand mat Chopped strand mat Surface veils

Photomicrograph (about 1500X) of cemented carbide with 85% WC and 15% Co

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MMCsLaminated composite

CMCs

Fiber reinforced polymer matrix

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Rule of mixture

▪ For particulate composites, the rule of mixtures predicts the density of the composite as well as other properties (although other properties may vary depending on how the dispersed phase is arranged)

▪ Density, r, is given as a fraction, f, as:

ffmmc ff fm ff 1 that Note

Where the subscripts m and f refer to the matrix and fiber.

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For fiber reinforced composites, the rule of mixtures predicts the density of the composite as well as electrical and thermal conductivity along the direction of the fibers if they are continuous and unidirectional.

Density, r, is given as a fraction, f, as:

ffmmc ff fm ff 1 that Note

For thermal conductivity:

ffmmc KfKfK ffmmc ff

For electrical conductivity:

Thermal and electrical energy can be transferred through the composite at a rate that is proportional to the volume fraction, f of the conductive material

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Bulk of energy transferred through matrix

But , in the fiber (polymer) composite, bulk energy transferred through fibers.

When the fibers are not continuous or unidirectional, the simple rule of mixtures may not

apply.

For example, in a metal fiber-polymer matrix composite, electrical conductivity would be

low and would depend on the length of the fibers, the volume fraction of fibers and how

often the fibers touch one another.

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Manufacturing methods

1) Hand lay up

2) Pre- preg forming

3) Pressure moulding

4) Vacuum bagging

5) Filament winding

6) pultrusion

7) Spray method

8) Sheet moulding

9) Bulk moulding

10)Resin transfer moulding

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1) Hand lay up

Low cost tools

Versatile: wide range of product

Time consuming

Possibility of trap of air bubble

inconsistance

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2) Prepreg forming

orientation of fibers can be changed

consistent

high productivity

continuous process needs more customers

limited shelf life

delamination

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3) Pressure forming

Advantages: wide range of shapes

integrate parts

Consistency

structural stability

relatively simple

Disadvantages high cost of machine

expensive molds (strong materials required)

no intricate parts

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4) Vacuum bagging

Advantages: simple design

any fiber/matrix combination

better quality for the cost

Disadvantages cannot be heated up

too much

breeder clothe has to be replaced frequently

low pressure (760 mm Hg the most)

slowest speed

inconsistency

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5) pultrusion

Advantages: Automated

processes.

High speed.

Versatile cross-sectional shape.

Continuous reinforcement

Disadvantage : Die can be easily

messed up.

Expensive die.

Mainly thermoset matrix.

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6) Spray method:-

Advantages : Continuous process

Any materials can be used as mold.

Error can be corrected by re-spraying.

Disadvantages : Slow.

inconsistency.

No control of fiber orientation.

Only one side finished.

Environmental unfriendly.

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7) Sheet moulding:

AdvantagesHigh productivity thus inexpensiveconsistency

Disadvantageslow volume fraction.Only board can be made.

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8) Bulk moulding

AdvantagesHighest volume fraction for short fiber reinforced composites (50%)Good mechanical propertiesFinish can be appliedInserts and attachments possible

DisadvantagesHigh temperature and high pressure Random fiber orientationCannot be used for intricate parts

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9) Resin transfer method:Advantages good surface finish on both sides accurate fiber management is

achievable Ability to build-in fiber volume

fraction loadings up to 65% Uniformity of thickness and fiber

loading, uniform shrinkage Inserts may be incorporated into

moldings Tooling costs comparatively low Uses only low pressure injection Low volatile emission during

processing Ability to produce near net shape

moldings Process can be automated,

resulting in higher production rates

Ability to mould complex structural and hollow shapes

Low resultant voids Ability to achieve from 0.5mm to

90mm laminate thickness

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conclusion

...And Just what is composite??

Let’s keep It simple

▪ A macroscale material “composed” of multiple non homogenious material

▪ More simpler definition ?? Okay...

▪ Its STRING and GLUE ..!!

▪ Its everywhere...starting from MANGALYAAN to an OPERATION theater in hospital.

▪ Why don’t customize the existing design when you have composite ...!!!

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