6.3 Aircraft Materials - Composite and Non - Metallic Flashcards
What is the calculation for Fahrenheit to Centigrade?
C = (°F − 32) × 0.555
What is the calculation for Centigrade to Fahrenheit?
°F = °C × 1.8 + 32
What is the description of the word composite?
Two or more materials that are combined to form a much stronger structure than either material by itself
What are the two most common elements of a composite?
- Matrix
- Reinforcing Material
What are the advantages of composite?
- High strength-to-weight ratio
- Reduction of parts and fasteners
- Reduction of wear
- Corrosion resistance
What are the disadvantages of composite?
- Generally expensive
- Not easy to repair; well-trained sta , tools, equipment and facilities are required to repair composite components.
What gives the major strength to the composite component?
reinforcing material
What type of material in Nomex
An infusible, wholly aromatic* polymer
How is aromatic polymer manufactured
As a fibre only
What are the advantages of Nomex?
Very high thermal stability and temperature and flame resistant. Along with highly radiation proof
How is fiberglass made?
Small strands of molten silica glass and than spun together and woven into cloth
What properties does E-glass have?
Resistant to electricity
What properties does S-glass have?
Very high tensile strength
What are the characteristics of glass fibre?
◦ Low density (2.1 g/cm3)
◦ High Strength
◦ Hight fracture toughness
◦ Circular cross-section and smooth surface
◦ Good ‘wet out’
◦ The bre does not absorb water/humidity
◦ The bre is not ductile (ceramic properties)
◦ For sanding, aluminium-oxide or silicon-carbide sand paper can be used. Silicon-carbide will last longer than aluminium-oxide
Glass Fibre Prepreg
What colour are aramid fibres?
Yellow
What is the full name of aramid
aromatic polyamide
What material will be used to repair aramid damage
fibreglass
Is aramid good in tensile or compressive loads
tensile
What are the characteristics of aramid fibres?
◦ Low Density (1.45 g.cm3) ◦ High tensile strength ◦ Heat resistance up to 260°C ◦ Non- ammable and non-fusible ◦ Good chemical resistance ◦ Very good resistance against abrasion ◦ High toughness
Is kevlar man-made or natural?
Man-made
What are the disadvantages of Kevlar?
The fibres themselves absorb moisture, making Kevlar composites more sensitive to the environment. Although tensile strength and modulus are high, compressive properties are relatively poor. Kevlar is also very di cult to cut. Special scissors are needed for cutting dry fabric and special drill bits for drilling cured laminates.
What happens to Kevlar when exposed to UV?
It turns brown
What is stronger under compression… Kevlar or Graphite?
Graphite
What material should fibreglass be kept from?
Aluminium
What is the two-part system for resins?
- Resin
- Hardener (catalyst)
What are the two types of plastics?
- Thermoplastic
- Thermoset
At what temperature does Thermoplastic remould?
750F
What is an example of Thermoplastic?
Acrylic
Plexiglass
What is an example of Thermoset?
Bakelite
Is Epoxy resin thermoset or thermoplastic?
Thermoset
What are the two types of honeycomb fabrication?
- Corrugation
- Expansion
What does the ribbon direction denote on Honeycomb cores?
The direction the honeycomb can be pulled apart
What are the four ways of dissipating electrical charge?
- Flame spray
- Bonding jumpers
- Aluminium wires woven into the top layer
- Thin aluminium foils bonded to the top layer
What is a monomer in plastic creation
A molecule of one of the gaseous hydro-carbons in the manufacture of plastic:
Ethylene.
What are 2+ molecules of Ethylene joined together called
Polymer
What by-products are created from polymerisation?
None
