Question

9) What is a common, high end, reinforcing material for polymer composites used in aircraft?

Please explain in clear words. Thanks

Answer 1

Carbon fiber–reinforced polymer, carbon fiber–reinforced plastic or carbon fiber–reinforced thermoplastic (CFRP, CRP, CFRTP or often simplycarbon fiber, or even carbon), is an extremely strong and light fiber-reinforced plastic which contains carbon fibers.

CFRPs can be expensive to produce but are commonly used wherever high strength-to-weight ratio and rigidity are required, such as aerospace,automotive and civil engineering, sports goods and an increasing number of other consumer and technical applications.

the composites used in airframe components are fibre reinforced polymer (FRP) matrix composites.

Airframe composites have the advantages of:

• high specific strength and stiffness
• tailored directional properties
• non-corroding in salt environments
• excellent fatigue resistance
• dimensional stability
• reduced number of parts required (compared to metal components).

However, these composites are susceptible to:

• impact damage
• moisture pick-up
• lightning strikes
• extremes of temperature.

irframe composites also have a relatively high cost, do not yield plastically in regions of high stress concentration and are subject to random property variation due to the nature of composite manufacturing processes.

The use of advanced composites in airframe construction has increased substantially over the past few decades. They are used as floor beams, doors, aerodynamic fairings and for control surfaces, such as rudders, elevators and ailerons, due to their low weight and high stiffness.

Reinforcing materials for polymer matrix composites are often referred to as fibres and they include (in order of increasing cost):

• E-glass
• aramid, kelvar
• carbon
• alumina
• silicon carbide
• boron.

These fibre materials all have high specific strength and stiffness imparting high strength and stiffness to the composite.