This document is a research paper about the usage of composite material in aerospace technology. Particularly our focus has been on the used of Kevlar in aerospace vehicles.

1. Kevlar used in aerospace
vehicles
By
Messina Atangana
annick fred

2. Contents
1.
2.
3.
4.
5.
6.
7.
Definition of a composite material
What is Kevlar?
Properties of a Kevlar
Manufacturing process of Kevlar
Advantages and disadvantages of using Kevlar
Applications of Kevlar in space vehicles
Conclusion

3. 1- Definition of a composite material
According to google definition, a composite material can be defined as a combination of a matrix and
reinforcement, which when combined gives properties superior to the properties of the individual
component. In the case of a composite, the reinforcement is the fibre and is used to fortify the matrix
in terms of strength and stiffness, it can simply be defined as a material made by combining two or
more materials to give a unique combination of properties. So as opposed to metal alloys, each
material retains its spread chemical, physical and mechanical properties. There are moderns
classifications of composite into (CCC)carbon-carbon composite and (IMC)intermetallic matrix
composite. They used instead of various materials in the fields in different applications din medicine,
civil engineering and military due to their specific properties such as strength and stiffness. But in our
case we are going to study Kevlar in space vehicles, as our example of a composite material.

4. Kevlar is a registered trademark for a synthetic fibre produced by DuPont, a chemical company. So it
is a synthetic fibre of high tensile strength use especially as reinforcing strength in the manufacture
of tyres and rubber products. And the chemical name for Kevlar is poly-para-phenylene
terephthalamide, with formula:

5. 3-Properties of a Kevlar
Kevlar as a composite material has many properties like:
strength to weight ratio is more.
Withstands temperature up to 450*C and low as -196*C.
Self-extinguishable
Resistant to almost all types of chemicals.
Negative coefficient of thermal expansion.
Abrasion resistance
High modulus of rigidity
Low ductility
Low electric conductivity
High toughness
Low machinability
These all properties enable the usage of Kevlar in various products individually and in composites
.

6. 4-Manufacturing process
The procedure for obtaining Kevlar undergoes in two steps.
a-Step 1(chemical synthesis)
Kevlar is synthesized in solution from the monomers 1,4-phenylene-diamine (para-
phenylenediamine) and terepththaloyl chloride in a condensation reaction yield hydrochloric acid.

7. b-steps 2(wet spinning)
The chemical obtained is turned into fibres by a process called wet spinning, which involved
forcing a hot concentrated, and very viscous solution a spinneret (a metal former a bit like a sieve)
to make lay, thin strong and stiff fibres that are wound into drums. The fibres are then cut to
length and woven into tough mat to make the super-strong, super-stiff finished material we know
as Kevlar. Later this fibres is woven into sheets. Which are high strength material, very high when
compared to its strength and also 5 times stronger than steel of same weight.

8. 5-advanatages and disadvantages of Kevlar
Advantages Disadvantages
Higher strength to weight ratio Absorb moisture
High tensile strength Poor compressive strength
Impact resistance Difficult to cut
Abrasion resistance Difficult to drill
Does not expand on heating Can degrade after high radiations doses
It has the lowest specific gravity Difficult to machine

9. 6-applications of Kevlar in space vehicles
A lot of space mission have required the use of Kevlar, in their equipment and also in their material. So Kevlar:
Was qualified for Viking and was used on Galileo for lines and risers.
Is extensively used on Huygens for lines, risers and reinforcement to reduce mass.
In astronauts outfits in order to protect them against radiations.
In the wheels of landing machines and vehicles in the space.
Is used in satellite antenna reflectors is these reflectors are made on Kevlar fibre or on Kevlar honeycomb.
Is used in astronauts clothes like gloves, jackets, shoes, helmet, etc...
Is used in aircraft and shuttle pipe during manufacture.
Is used in shrapnel-resistant shielding in jet aircraft engines that will protect passengers in case an explosion
occurs.
Is mainly used in aerospace for weight reduction and increase fuel efficiency.
Is found flooring to interior walls to wing flap to engines.
“Kevlar helped airbus which is concept of the world largest aircraft to become a reality “, said Jim Weigand
who has written about DuPont sustainable solutions.

10. 8-conclusion
The selection of an innovative material for space vehicles amelioration is typically driven by its
capability to respond to a specific requirement. For non-metallic materials, the compatibility with the
various space vacuum and thermal cycling must be carefully assessed. So Kevlar behaviour in space
environment, and in particular its outgoing properties, resistant to hypervelocity impacts and particle
radiation shielding have been well characterized as individual material and in combination with other
materials.