KEVLAR2SUBBU

8/22/2019 KEVLAR2SUBBU

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KEVLAR


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Kevlar is a material formed by combining para-

phenylenediamine and terephthaloyl chloride.

Aromatic polyamide (aramid) threads are the result.

They are further refined, by dissolving the threads and spinning

them into regular fibres.

When woven, Kevlar forms a strong and flexible material.

Kevlar is expensive due to the demands of the manufacturing

process and the need for specialist equipment.

INTRODUCTION


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Chemical composition


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TYPES

Kevlar AP

K29

K49

K100 K119

K129

KM2

KM2 PLUS


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ADVANTAGES AND DISADVANTAGES

Kevlar is relative low weightand high strength.

Kevlar is often combined

with other materials, to

produce textiles with

enhanced properties, such

as fire resistant clothing for

the Fire Services.

It retains its flexibility

The material cannot be

pieced by other carcomponents, even during a

high speed impact

Kevlar textiles tend to absorbmoisture. It must be combined

with moisture resistant

materials.

Kevlar reacts well under a

tensile force (stretching force)

but badly under a compressiveforce.

Kevlar reacts badly to UV light

(sunlight) unless it is

protected .

Kevlar suffers some corrosion

if exposed to chlorine. It is difficult to cut and shape,

unless through the use of

special tools and equipment.


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APPLICATIONS

Ropes and cables

Auto hoses and belts

Composite materials

Mooring lines

Tires

Fiber optic cables

Climbing ropes

Escape ropes for firefighters

Umbilical hoses on offshore

oil and gas refineries

Sporting goods, such as

tennis rackets, lacrosse

sticks and canoes


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AEROSPACE

APPLICATIONS


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Aircraft cabin flooring and interiors

Aircraft cabin floors, overhead bins, and bulkheadsbuilt with Kevlar honeycomb cores have helped in

weight savings for aircraft manufacturers. Inaddition to the lighter weight, honeycomb has verylow electrical conductivity and high fire resistance,which helps contribute to addressing the safety

standards the industry demands. The superiorthermal and sound insulation also contribute topassenger comfort.


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Landing gear doors

Kevlar honeycombs help designers produce

landing gear doors that are strong and light to

allow for delivering more efficient aircraft


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Wing boxes and control surfaces

The light weight, lack of galvanic

corrosion, and overall strength that or

Kevlar honeycombs help provide for

wing-to-body fairings and controlsurfaces make it superior to the heavier,

weaker, and corrosion-susceptible

aluminum core that has been used in thepast.


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Filament-wound pressure bottles

Bottles containing pressurized oxygen (orother gases) on airplanes use moldedcasings made of Kevlar filament to helpreduce the overall weight of the aircraft. Anordinary alloy-encased bottle can suffercatastrophic failure, releasing metalfragments into the aircraft at high velocity,whereas a bottle using a casing made ofKevlar may help risk ductile failure

rupturing, rather than disintegratingwhich does not result in fragmentation.


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Engine nacelles

The nacelles that surround jet engines must

contend with thrust, lift, and vibration forces.

Manufacturers choose to use or Kevlar

honeycomb core structures in engine nacelles

because it is far stronger and lighter than

earlier designs with an aluminum core.


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Engine containment rings

Many jet engine manufacturers add a

protective layer of Kevlar fabric inside the

engine cowl to help catch errant fan blades or

massive broken parts flung outward by the

engines centrifugal force, thus potentially

preventing them from damaging the wing or

the cabin.


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Aircraft tires

Landing and takeoff cycles, friction, and rapid

changes in temperature push aircraft tires to

their stress limits. Tires reinforced with Kevlar

brand aramid fiber help provide enhanced

toughness and thermal stability.


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Rotorblades

The alloy cores that historically predominated

helicopter rotor blade designs are giving way

to composites, of which honeycomb core

made of Kevlar is proving to be a material of

choice. Modern helicopters are redefining

efficiency and performance with lighter, stiffer

rotor blades made of Kevlar.


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Spacecraft

Kevlar fiber has proven that it is strong enough tosurvive the extreme forces and temperaturefluctuations of space travel. When the MarsPathfinder landed on the surface of Mars, Kevlar

fiber reinforced the inflatable landing cushionsand the ropes that secured them helping thePathfinder to complete its 40-million-milejourney fully intact and ready to explore the

planets surface. Kevlar is used incommunications satellites, and also in the spaceshuttle, to help protect against impact fromorbital debris.


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END

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