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> Aramid.
Aramid
fibres have the highest strength to weight ratio compared
to other commercially available fibres. There are a number
of manufacturers, with Kevlar (manufactured by DuPont) being
a familiar brand name. Aramid is broadly similar in tensile
strength to glass fibre, but can have up to twice the modulus.
Toughness
is an advantage where energy absorption is required, but,
compared to carbon, it is lower in compressive strength and
has poorer adhesion to the matrix. It is also susceptible
to the uptake of moisture.
Aramid
fibre properties depend on the structure used and can be tailored
for high toughness or high modulus. Indicative materials properties
are:
| |
Kevlar
29 High toughness |
Kevlar
49 High modulus |
Kevlar
149 Ultrahigh modulus |
| Tensile
Strength |
3.6
GPa |
3.6-4.1 GPa |
3.4
GPa |
| Young's
Modulus |
83
GPa |
131
GPa |
179
GPa |
| Elongation
at break |
4% |
2.80%
|
2.0% |
Ref
ASM Vol 21 Handbook.
|
