Benefits
Composites can be used:
- When high stiffness or strength-to-weight ratios are desired.
- When high fatigue strength, corrosion resistance, resistance to fracture, impact, and creep resistance are required.
- Under harsh environmental conditions due to their low thermal and hygric coefficients of expansion.
The high stiffness and strength-to-weight ratio makes composites appealing for use in a wide variety of applications. For example, composites are used in airplanes mainly for overall mass reduction. The initial material costs are high but there is a significant reduction in fuel cost during operation.
Their low thermal coefficient of expansion for example, make them attractive for use in satellites in space where huge temperature changes occur.
Applications
Composites are utilized in many applications ranging from aircraft and automobile parts to bio-medical implants and recreational products. Some examples are listed below:
- Aircraft components - Engine cowlings, outer wing, belly fairing skins, nose landing gear doors, and tail cone among others.
- Space shuttle components- Sleeves, vent lines, and fuselages.
- Helicopters - Rotor craft blades (graphite-epoxy composites).
- Automobiles - Bodies made of carbon fiber composites or fiberglass composites.
- Boats - Hulls (wood or Kevlar).
- Bio-medical industry - Implant materials.
- Recreational products - Bicycle frames, rackets, skis, and golf club shafts.
Limitations
- Difficulty of damage (intra-ply and inter-ply) detection. This requires expensive non-destructive evaluation techniques or structural health monitoring systems.
- Difficulty in determining material constants as they are usually orthotropic.
- Low fracture toughness for same strengths compared to metals.