Manufacturing Technology: Composites Processes

Vocabulary flashcards covering the definitions, properties, and manufacturing processes of composite materials as presented in the lecture notes.

Composite material

A combination of two or more dissimilar materials used together to impart a specific set of characteristics or properties that neither constituent material can achieve on their own.

Specific gravity

Ratio of the mass of a material to the mass of an equal volume of water at $4\,degC$.

Glass fibre (E glass)

An inorganic, isotropic fibre with a modulus of $70\,GPa$ that is strong due to a lack of defects ($>3\,GPa$ as made) but susceptible to environmental attack and fatigue.

Carbon fibre

An inorganic, anisotropic fibre with highly aligned planes of graphite, a modulus from $160-700\,GPa$, and resistance to chemical degradation and fatigue.

Aramid fibre (Kevlar)

An organic, highly anisotropic material strong due to highly aligned linear polymer chains ($>3\,GPa$), with a modulus of about $125\,GPa$ and susceptibility to UV light and moisture.

Phenolic resin

The first modern matrix resin; it is brittle, heat and fire resistant, produces water as it cures, and does not produce toxic gases in a fire.

Polyester resin

The commonest matrix resin in tonnage terms; it cures with catalysts at low temperature, wets out reinforcements very well, but burns easily.

Epoxy resin

The commonest matrix resin in aerospace, typically curing at elevated temperatures with a refrigerated shelf life of up to a year.

Core materials

Materials such as foam or honeycomb used to make sandwich panels to provide stronger and stiffer structures at minimum weight.

Polymethacrylimide (PMI) foam

A core material normally used in aerospace (e.g., Rohacell) with a maximum use temperature of approximately $180\,degC$.

Honeycomb (H/C)

A set of vertical strips of material (often aluminium or Nomex) in a hexagonal array that is stronger and stiffer than foam for a given density but harder to work with.

Direct processes

Manufacturing methods that use separate fibres and resin which are brought together at the point of moulding.

Indirect processes

Manufacturing methods that utilize pre-impregnated fibres (prepregs).

Contact moulding

A direct manufacturing process with very low material costs but poor reliability, poor property flexibility, and high finishing requirements.

Compression moulding

A process with good productivity for larger volumes where mould cycles are short, though tooling costs are expensive and geometrical flexibility is limited.

Vacuum Bagging & Autoclave Cure

A high-reliability manufacturing process for lightweight structures where plant costs for large autoclaves can exceed $£1,000,000$.

Advanced fibre-reinforced composites manufacturing

A unique manufacturing scenario where the material and the structure are created at the same time.

Thermosets

A category of matrix resins for PMCs including Phenolic, Unsaturated polyester, Epoxy, and Vinyl ester.

Thermoplastics

Matrix resins such as PEEK, PEI, and PPS that can be processed and reshaped with heat.