Presentation- Javed (1)

8/7/2019 Presentation- Javed (1)

1/43

GRAPHITE REINFORCED

COMPOSITES

TO

DR.AHMAD TINDYALA

BY: Muhammad Javed

2009-MS-PE-10


2/43

Contents

Introduction to CFRPC

Types of Carbon Fiber

DIFFERENT GRAPHITE REINFORCED COMPOSITES

ADVANTAGES OF CFRPC

DISADVANTAGES OF CFRPC

MANUFACTURING PROCESSES

Applications


3/43

Carbon Fiber Reinforced Polymer

(CFRP) is a Polymer Matrix Composite

material reinforced by carbonfibers.

The reinforcing dispersed phase may be inform of either continuous or discontinuous

carbon fibers of diameter about 0.0004

(10 mkm) commonly woven into a cloth.

Carbon fibers possess the highest specificmechanical properties: modulus of

elasticity and strength.


4/43

Carbon Fiber Reinforcement

Most expensive reinforcement.

In aerospace applications the combinationof excellent performance characteristicscoupled with light weight make the cost of

secondary importance.

Today, high cost carbon fiber alone and inhybrid form is widely used in highperformance applications where

performance to cost advantages exist.4


5/43

Properties of CRPC

Very high modulus of elasticity exceeding

that of steel

High tensile strength, which may reach1000 ksi (7 GPa);

Low density: 114 lb/ft (1800 kg/m);

High chemical inertness.


6/43

Disadvantage

Catastrophic mode of failure (carbon fibers

are brittle).

Cost

Heterogeneous Anisotropic


7/43

Types of Carbon Fibers

UHM (ultra high modulus). Modulus of elasticity

> 65400 ksi (450GPa).

HM (high modulus). Modulus of elasticity is in

the range 51000-65400 ksi (350-450GPa). IM (intermediate modulus). Modulus of elasticity

is in the range 29000-51000 ksi (200-350GPa).

HT (high tensile, low modulus). Tensile strength> 436 ksi (3 GPa), modulus of elasticity < 14500

ksi (100 GPa).

SHT (super high tensile). Tensile strength > 650

ksi (4.5GPa).


8/43

8

Carbon (IM)

A variety of fiber grades are produced:

Carbon (HM)

Carbon (UHM)

Intermediate Modulus

High Modulus

Ultra-high Modulus

Typically, the stiffer the

fibre, the lower the

strength and strain to

failure.

Grades of Carbon FiberReinforcement


9/43

Manufacturing of Carbon Fiber

Reinforcement

9

There are a number of precursors for the

development of carbon fibers including

Cellulose fiber

Polyacrylonitrile fiber

Lignin

pitch

High strength, highmodulus

Largely produced by

these precursors

Lower strengthfiber


10/43

Manufacturing of Carbon Fiber

Reinforcement Carbon fibers are produced by controlled

oxidation and carbonization of the precursorfiber at temperatures up to 2600C resulting inhigh strength fiber

Increasing the temperature to 3000C results inthe conversion of high strength fiber to highmodulus graphite fiber

Conversion of polyacrylonitrile fiber to carbon

fiber is more efficient than that using cellulosefiber, owing to high carbon content of precursor.

Sizing with a resin also improves handling andprevents damage during processing

10


11/43

Manufacturing Method

. PAN-based carbon fibers (the most

popular type of carbon fibers).

CFare produced by conversion ofpolyacrylonitrile (PAN) precursor

PAN manufacturing

process:


12/43

Pitch-based Carbon Fibers

Carbon fibers of this type aremanufactured from pitch:

Filaments are spun from coal tar or

petroleum asphalt (pitch). The fibers are cured at 600F (315C).

Carbonization in nitrogen atmosphere at a

temperature about 2200 F (1200C).


13/43

Pitch-based Carbon Fibers


14/43

14


15/43

Matrix Materials forManufacturing CFRP

The most popular matrix materials for

manufacturing Carbon Fiber ReinforcedPolymers (CFRP) are thermosets such as

epoxy, polyester and thermoplastics suchas nylon (polyamide).

Carbon Fiber Reinforced Polymers

(CFRP) materials usually have laminatestructure, providing reinforcing in twoperpendicular directions.


16/43

Graphite in Epoxy Resin

Graphite addition reduces the friction coefficient andwear loss drops significantly when graphite is presentin small amounts in the resin.

composites containing 3wt% or more of graphiteyielded extremely small amounts of wear.

Material thickness and fiber orientations can beoptimized for each application


17/43


Surface resistance and resistivity

Surface resistance and resistivity decreased together bydecreasing of specimen thickness. It is obvious result ofincreasing content of graphite filler in sequential, deeper

placed layers. Addition of 3 to 6%vol. of graphite toepoxy resin caused limited, almost linear, decrease ofsurface resistance and resistivity in depth direction ofspecimens. But addition of 9 to 12%vol of graphite inpolymeric composite caused rapid, non-linear with layer

depth, decrease of surface resistance and resistivity. It isin accordance with possibility of forming spatial networkby conductive filler particles


18/43


Surface resistance and resistivity

Results scatter for composite with 12%vol of graphite

was probably caused by non-homogenous fillerdistribution in composite volume. High viscosity of this

composite made mixing very difficult.


19/43

Graphite Fiber-reinforced

Polyimide Composites Polyimide/graphite fiber-reinforced composites are widely

applied to the manufacture of various aerospace structures.The main advantage of polyimide composites is their ability

to retain In plane mechanical properties at temperatures up to

250 to 350C which is the result of a very high glass transitiontemperature of a polyimide matrix.

These composites are successfully applied in the Application:

Aerospace honeycomb design, providing significant weight

reduction and long-term functioning at increased temperatures.Typically, such honeycomb panels include graphite fiber-reinforced polyimide sheets adhesively bonded to the fiberglass core


20/43

Disadvantage:

low interlaminar fracture toughness and tendency to

delaminating. This arises from the three dimensional stressfield and the presence of transverse stresses

M t l M t i C it


21/43

Metal-Matrix Composite

Materials and Applications

The metal matrix composites offer higher modulus ofelasticity, ductility, and resistance to elevatedtemperature than polymer matrix composites. But, theyare heavier and more difficult to process


22/43


23/43

CFRP are Characterized bythe Following Properties

Light weight;

High strength-to-weight ratio;

Very High modulus elasticity-to-weight ratio;

High Fatigue strength;

Good corrosion resistance;

Very low coefficient of thermal expansion

Low impact resistance

High electric conductivity;

High cost.

G l Ch t i ti f C it


24/43

General Characteristics of Composite

MaterialsComparison with CRPC

Fibers

Matrix materials


25/43

25

Tensile Stress-Strain Curves for different

Fiber/Epoxy Systems, Aluminum and Steel


26/43

26


27/43

27


28/43

28


29/43

Utilization of Carbon Fiber

Reinforcement

Carbon fibers are supplied in a number ofdifferent forms, from continuous filament toes tochopped fiber mat

Highest strength and modulus are obtained byusing unidirectional reinforcement.

Twist free tows of continuous filament carbon

contain 5000-10000 individual filaments whichcan be woven into woven roving and hybrid

fabrics with glass fiber and poly-aramid fiber

29


30/43

Graphite Reinforced composites

The graphite fiber sheets may be impregnatedwith, and bonded together by, any suitable resin

during preform manufacture. Impregnation may be accomplished by any

suitable technique, such as solution dipping,spraying, hot-melt coating, etc.


31/43

CFRP are used forManufacturing

Automotive marine and aerospace parts

Sport goods (golf clubs, skis, tennisracquets, fishing rods)

Bicycle frames.

Electronic and electrical industries


32/43

Composite Materials withinthe Aerospace Industry

Graphite/Carbon

Fiberglass

Kevlar

Thermoset Plastic


33/43


34/43


35/43

Courtesy : Gary Eisenberg; Antelope Valley Community College; Lancaster , CA

Composites-Boeing 777

Composites B2 Stealth Bomber


36/43

Courtesy : Gary Eisenberg; Antelope Valley Community College; Lancaster , CA

Composites B2 Stealth Bomber

Weight Savings for Automotive Light


37/43

Lightweight Material Material Replaced

Mass Reduction (%)

High Strength Steel Mild Steel 10

Aluminum (AI) Steel, Cast Iron 40 - 60

Magnesium Steel or Cast Iron 60 - 75

Magnesium Aluminum 25 - 35

Glass FRP Composites Steel 25 - 35

Graphite FRP Composites Steel 50 - 60

Al matrix Composites Steel or Cast Iron 50 - 65

Titanium Alloy Steel 40 - 55

Stainless Steel Carbon Steel 20 - 45

Weight Savings for Automotive Lightweighting Materials


38/43

Manufacturing of Graphitic Foam

A suitable graphite foam can be made by dissolving atelevated temperatures (about 300C.) and pressures

as much nitrogen as possible into a high qualitymesophase pitch. When the pressure is relieved, the

nitrogen expands, forming a pitch foam. The pitchfoam is then oxygen stabilized at about 200-250C.to crosslink the pitch to strengthen the foam. Finally,

the pitch foam is heat treated at high temperatures(about 2,000-2,500F.) in an inert atmosphere to forma graphite foam.

Graphitic Foams


39/43

Graphitic Foams

Properties of the foam

an isotropic bulk thermal conductivity as high as 150W/mK

specific conductivity up to 6 times greater than that of copper

high thermal conductivity, low weight, low density, 0.27 to 0.57g/cm3

low coefficient of thermal expansion,

high specific strength and low cost

Graphitic open celled network throughout the foam (unlikecarbon fiber reinforced composites)

A dramatically smaller automobile radiator has been developedwith the foam.

Applications of Foam


40/43

Applications of FoamThis material is an enabling technology for thermal

management problems ranging from Heat sinks

Radiators Satellite panels to aircraft heat exchangers. High-density electronics

Hybrid diesel-electric vehicles Communication satellites

In addition, the open porosity will lead to novel designs

that incorporate porous media heat exchangers and phasechange materials. For example, by utilizing the foam as aheat exchanger, heat transfer coefficients over two orders

of magnitude greater than current metallic designs havebeen measured.


41/43

Foam heat sink in Pentium 133 microprocessor

Computer chip heat sinks made from graphitic foam


42/43


43/43

THE END

Documents

Presentation- Javed (1)