Materials Flashcards
Common materials in a/c
Aluminium, titanium, magnesium alloys and steel
Most common aluminium alloy used and its benefits and drawbacks
Duralumin
A copper based alloy
Is good at thermal and electrical conductivity with a good strength to weight ratio
Susceptible to corrosion and difficult to weld
Alclad
Sheet of duralumin with aluminium coating n the outside for protection from corrosion
Composite materials
Made of at least 2 elements to produce a material with properties that are different to this of original elements
Nearly all composites consist of a bulk material called the matrix and some form a reinforcement - usually fibres
Benefits of composites
High specific strength
Specific thickness
Have the ability to retain those properties at elevated temps
It can also tailor strength to the direction of the load
Examples of composites
Glass
Carbon
Aramid
Sandwich construction and examples of where its used
Honeycomb core with skins of composite materials or aluminium alloy
Typically used for flight control surfaces, flooring, fuselage panels, empennage skin and sound proofing engines
Advantages and disadvantages of sandwich construction
Has a good strength to weight ratio - particularly strong in the direction of the honeycomb openings
Not very good at handling concentrated loads - need additional provision (load spreaders)
An alloy
Combination of 1 or 2 metals that have been worked together to get different properties
Composites save operating costs by
20%
50% of the materials in the A350/B787 are made from composites
Purpose of glass fibre on the nose
Radio waves can pass through it easily
Hard time maintenance
Item must be removed from the a/c for inspection and possible repair/replace
On condition maintenance
Visual inspection, measurements/tests without dissembling inspection overhaul
Break pin still visible = brake pads are okay
