Advanced composites Flashcards
What is a composite?
A uniform material created by the combination of 2 or more materials to obtain specific physical characteristics and properties
Properties of advanced composites
high strength to weight ratio
high stiffness
Classes of materials
matrix(body)
reinforcement
Types of reinforcement
fibrous(long or short fibre) flake laminar particulate skeletal
Typical fibre reinforcement materials
Glass fibre(E & S glass)
Carbon fibre(graphite)
Kevlar
Boron
Polyester properties, advantages and disadvantages
low-temperature resistance(+/- 60 C)
cheap
shrinkage problems
Advantages of graphite
high strength to weight ratio, rigid
conductive
best balance of mechanical properties, cost and manufacturing considerations
Disadvantages of graphite
low-temperature resistance
relatively brittle
manufacturing process can be labour intensive
hard to inspect/repair in service
Advantages of kevlar
relatively flexible
good impact resistance and low mass
Disadvantages of kevlar
low compressive strength
Properties of fibreglass
low cost low stiffness easy to use lower strength to weight than carbon fibre more flexible than carbon fibre non-conductive transparent to electromagnetic radiation
Advantages of boron fibre
high strength and stiffness
good fatigue resistance
Disadvantages of boron fibre
brittle
high cost
difficult manufacturing aspects
Advantages of composites
resistance to corrosion reduced manufacturing processes bespoke strength and stiffness low thermal expansion stealth- radar microwaves absorbed reduced parts count complex shapes can be easily produced
Disadvantages of composites
limited manufacturer knowledge base
expensive and complicated inspection methods
poor energy and impact absorption
susceptible to UV radiation degradation
hard to repair
difficult to determine internal defects
degradation of mechanical properties under extremely high temperatures and wet conditions
