Aircraft Materials: Composite and Non-Metallic

This set of vocabulary flashcards covers various aircraft materials, specifically focusing on plastics, elastomers, resins, and composite manufacturing processes as per the Ryanair Engineering training module.

Plastics

The generic name for natural and synthetic materials based on long-chain polymers of carbon that can be extruded, moulded, or drawn into filaments for fibers.

Thermoplastic Materials

Materials that are hard in their normal state but become soft and pliable when heated ($thermo$), allowing them to be reshaped repeatedly without damage.

Thermosetting Materials

Also called Thermosets, these materials initially soften when heated but set (harden) permanently if heat continue to be applied; the process is irreversible.

Curing

The process of thermosets becoming hard when heated or through chemical (exothermic) reactions, capable of handling temperatures up to $250 \text{ }^{\text{o}}\text{C}$.

Polyester Resin

A clear, hard, and brittle thermosetting resin with high UV resistance, commonly used for boat hulls and car bodies when reinforced with glass fibers.

Epoxy Resin

A thermosetting resin with exceptional adhesive qualities, low shrinkage, and high strength, most commonly used for aircraft parts.

Melamine Formaldehyde

A thermoset with a very hard surface highly resistant to ignition, typically used for hygienic and attractive counter tops.

Phenolic Resin

A strong, hard, and rigid thermoset, usually black or brown in colour, used for items like pan handles and knobs.

Micro-balloons

Inert fillers such as Cotton, Glass, or Aerosil (fumed silica) added to resins to thicken them and provide more body.

Styrene Monomer

A solvent added to thick polyester resin to make it thinner and easier to work with.

Inhibitors

Chemicals added to resin mixtures to delay the curing process and improve shelf-life.

Elastomers

Natural or synthetic polymers with considerable elastic properties that can tolerate repeated elongation and return to their original shape, such as rubber.

Fluoro-Elastomers (Viton)

Expensive, solvent-resistant materials with exceptional high-temperature properties (up to $250 \text{ }^{\text{o}}\text{C}$) used mainly for high-temperature seals.

Casting

A manufacturing process where molten material is poured into a mould and allowed to set.

Extrusion

A process where plastic is forced through a shaped die to form endless shapes which can then be cut to length.

Lay-up

A process where load-carrying plastic fibers and an adhesive are layered in a mould or around a former.

Sandwich-Construction

A structure where plastic facings are placed around a honeycomb or foam core to create very stiff but light components.

Vacuum Forming

A process where material is sucked down to a mould by vacuum rather than being pressed, commonly used for aircraft interior trims.

Composite Material

An engineered substance formed by combining a reinforcing agent (Fiber) and a matrix (resin) to create properties superior to the individual components.

Lamina

A single layer of composite material with a unidirectional fiber orientation.

Laminate

A material formed by multiple layers of fibers, often in a bidirectional orientation typically $90 \text{ }^{\text{o}}$ apart, to spread loads evenly.

Quasi-Isotropic lay-up

Stacking multiple layers of unidirectional or bidirectional fibers in specific sequences such as $0 \text{ }^{\text{o}}$, $-45 \text{ }^{\text{o}}$, $+45 \text{ }^{\text{o}}$, and $90 \text{ }^{\text{o}}$.

Warp

The longitudinal fibers of a fabric, representing the highest strength direction due to fiber straightness ($0 \text{ }^{\text{o}}$ direction).

Weft

The transverse fibers of a fabric, perpendicular to the warp ($90 \text{ }^{\text{o}}$ direction).

Pre-Impregnated Products (Prepregs)

Materials consisting of a combination of resin and fibers that must be stored at temperatures below $0 \text{ }^{\text{o}}\text{F}$.

E-Glass

A type of glass fiber used for electrical applications due to its high resistance to current flow.

S-Glass / S2-Glass

Glass fibers identified for structural use because they have higher strength than E-glass.

Kevlar

DuPont's brand name for aramid fibers, which are light, strong, and tough.

Hygroscopic

The property of a material, such as aramid fibers, to absorb moisture; Kevlar can absorb up to $8 \text{ }\text{\%}$ of its weight in water.

Carbon Fibers

Very stiff and strong fibers (3 \text{ \times } to 10 \text{ \times } stiffer than glass) used for primary aircraft structures, but highly corrosive to aluminium.

Stage A (Ramp-up)

The initial curing stage where resin is mixed and debulks under vacuum to spread evenly before the chemical reaction begins.

Stage B (Curing)

The stage where the chemical reaction starts, resin becomes thicker and tacky, and temperature remains stable for the duration.

Stage C (Ramp-down)

The final stage where the resin is cured and the temperature is lowered step by step while vacuum is maintained to prevent warping.