Carbon Fiber Technology
Core Properties
Carbon fiber-reinforced polymers (CFRP) combine exceptional strength with minimal weight. The material consists of two key components: carbon fiber reinforcement and a polymer matrix. The carbon fibers provide strength and rigidity, while the matrix (typically epoxy resin) binds the fibers together.
Structural Composition
The carbon filaments measure 5-7 micrometers in diameter and form through a heating process that removes non-carbon atoms. Manufacturers create these fibers from precursor materials like polyacrylonitrile (PAN), rayon, or petroleum pitch. The resulting material delivers a strength-to-weight ratio that surpasses traditional metals.
Performance Characteristics
Carbon fiber exhibits directional strength properties, unlike metals such as steel or aluminum. The material’s performance depends on:
- Fiber orientation in the composite
- Ratio of carbon fibers to polymer matrix
- Quality of the binding process
Environmental Response
The material shows excellent corrosion resistance but can face challenges with moisture and temperature variations. While the carbon fibers remain stable, moisture can affect the polymer matrix, impacting compression and impact properties. Manufacturers address this by:
- Using specialized epoxy matrices
- Applying protective coatings
- Engineering specific fiber layouts
Manufacturing Methods
The production process involves layering carbon fiber sheets in specific orientations. Common techniques include:
- Vacuum bagging for precise fiber alignment
- Compression molding for rapid production
- Filament winding for complex shapes
Practical Limitations
Despite its advantages, carbon fiber shows some constraints:
- No definable fatigue limit
- Susceptibility to impact damage
- Complex failure modes
- Higher production costs than traditional materials
The material continues to evolve through research into tougher polymer matrices and improved manufacturing processes.
Carbon Fiber’s Strength-to-Weight Performance
Carbon fiber demonstrates exceptional strength-to-weight characteristics compared to traditional materials. The specific strength measurements show:
- Carbon fiber: 2,457 kN·m/kg
- Aluminum alloy: 115-204 kN·m/kg
- Steel alloy: 254 kN·m/kg
- Titanium: 76 kN·m/kg
Density Advantages
The material’s lightweight properties stem from its low density:
- Carbon fiber: 1.55-1.8 g/cm³
- Aluminum: 2.7 g/cm³
- Steel: 7.85 g/cm³
- Titanium: 4.5 g/cm³
Performance Benefits
Carbon fiber’s structural advantages include:
- 2x greater specific stiffness than aluminum or steel
- 5x higher specific strength than aluminum
- 4x higher specific strength than steel
https://en.wikipedia.org/wiki/Carbon-fiber-reinforced_polymers
Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon composite, or just carbon, are extremely strong and light fiber-reinforced plastics that contain carbon fibers. CFRPs can be expensive to produce, but are commonly used wherever high strength-to-weight ratio and stiffness (rigidity) are required, such as aerospace, superstructures of ships, automotive, civil engineering, sports equipment, and an increasing number of consumer and technical applications.
The binding polymer is often a thermoset resin such as epoxy, but other thermoset or thermoplastic polymers, such as polyester, vinyl ester, or nylon, are sometimes used. The properties of the final CFRP product can be affected by the type of additives introduced to the binding matrix (resin). The most common additive is silica, but other additives such as rubber and carbon nanotubes can be used.
Carbon fiber is sometimes referred to as graphite-reinforced polymer or graphite fiber-reinforced polymer (GFRP is less common, as it clashes with glass-(fiber)-reinforced polymer).