XIII. Read the extract and answer the question below. Carbon Fiber Reinforced Polymer (CFRP)

XI. Read the conclusion and compare with yours.

X. Read texts about Future Composite Materials and write your own opinion in conclusion.

Spider Silk Fibres

Spider silk is another promising material for composite material usage. Spider silk exhibits high ductility, allowing stretching of a fibre up to 140% of its normal length. Spider silk also holds its strength at temperatures as low as -40°C. These properties make spider silk ideal for use as a fibre material in the production of ductile composite materials that will retain their strength even at abnormal temperatures. Ductile composite materials will be beneficial to an aircraft in parts that will be subject to variable stresses, such as the joining of a wing with the main fuselage. The increased strength, toughness and ductility of such a composite will allow greater stresses to be applied to the part or joining before catastrophic failure occurs. Synthetic spider silk based composites will also have the advantage that their fibres will be biodegradable.

Many unsuccessful attempts have been made at reproducing spider silk in a laboratory, but perfect re-synthesis has not yet been achieved.

Due to their higher strength-to-weight ratios, composite materials have an advantage over conventional metallic materials, although, currently it is expensive to fabricate composites. Until techniques are introduced to reduce initial implementation costs and address the issue of non-biodegradability of current composites, this relatively new material will not be able to completely replace traditional metallic alloys.

XII. Do you agree or disagree with this conclusion? Express your opinion and justify it.

This composite material is commonly referred to by the name of its reinforcing fibers, namely carbon fibers. To manufacture, e.g. body parts for race cars, carbon fibers are embedded as reinforcement into a matrix, which usually epoxy. This is done by layering sheets of carbon fibers into a mold in the shape of a final product, the arrangement of the cloth fibers depending on the desired strength and stiffness properties of the product. The mold is the filled with epoxy and heated or air cured.

CFRP is a technologically important material. It is very strong and light-weight, non-corroding, heat-resistant, will not ignite^* and shrinks very little when exposed to high temperature. Unfortunately carbon fibers are expensive to manufacture.

^*to ignite - to start to burn, make sth start to burn

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