Composite Materials Flashcards
What is anisotropic?
Materials with strength in one direction only
What is Isotropic?
Materials that have the same strength in any direction
What are the 4 main dry fibre cloth weave patterns in use?
Unidirectional
Plan (or square)
Twill
Satin
What are the advantages of composite materials?
High strength to weight ratio
High stiffness
Fatigue resistance
Design flexibility
Disadvantages of composite materials?
Low impact damage
Degradation from fuels, oils, lubricants and UV light (environmental damage)
What environmental damage are composite materials prone to?
Fuels
Oils
Lubricants
UV Light
What five fibres are used in composite construction?
Glass fibre
Boron fibre
Carbon fibre
Aramid fibre
High performance polyethylene
Whats pre preg composites?
Pre impregnated with a matrix material.
Advantages - formability prior to its cure, good strength after cure
Disadvantages - refrigeration & special handling required
Whats wet lay-up?
Dry fabric saturated with matrix material (bonding) then stacked one ply at a time. Can be stored at room temperature for longer as resin can be mixed immediately prior to use.
Whats fibre orientation?
A manufacturer can tailor the directional strength and stiffness by simply changing the direction of the lay of the ply layers within it.
Disadvantages of composites?
Low impact resistance
BVID
Can be affected by:
Excess heat and moisture
Fuels, oils, lubes, and UV Light
What can wind erosion do to composite materials?
Panel edge delamination
What can sand erosion do to composite materials?
Severe abrasion damage
How can maintenance activities harm composites?
Careless over tightening of screws
Dropped tools/ components
Physical damage types on composite materials?
Collison
Weather
Sand erosion
Wind erosion
Careless Maintenance
Incorrect handling
Overheat damage
Hot air leaks
Lightning strike
Chemical damage
Common composite materials components on aircraft?
Cabin roof
Fairings
Panels
Doors
Armoured seats
Rotor blades
What PPE should be worn during CM handling?
Eye protection
Gloves
Aprons
Respirators
What material has conductivity that electrical components need to be protected against from contamination by its dust or fibres
Carbon fibre
Why do we not use solvents to remove resin from our skin?
Solvents dissolve natural skin oils that result in drying and cracking of skin rendering it susceptible to infection.
Whats HEPA?
High efficiency particulate air
Used for high dust generating activities
Where should liquid resins and pastes be mixed?
In an exhaustive hood
How close should an emergency eye wash station be to areas working with composites?
30m (100ft)
Personal hygiene when working with composites:
Wash with soap and water before breaks and end of shift.
Don’t eat smoke drink in composite work areas.
Disposable coveralls discarded or reusable washed separately
How do you clean liquid resins and paste adhesives from work areas?
Solvents
How to clean composite dust from work areas?
Using a HEPA vacuum, DO NOT dry sweep or use forced air.
What to do if you get resin in eyes?
Flush with water for 15 minutes
Remove contact lenses
Seek medical attention along with SDS
What to do if resin is inhaled?
Remove person to fresh air at once, seek medical attention with SDS
What action should you take in event of a runaway exothermic reaction?
Do not handle or approach container or attempt to control reaction
Do not breathe toxic gases
Evacuate area immediately, do not return until reaction is complete
Ventilate workspace to remove toxic exothermic reaction product
How should you dispose of carbon fibre materials?
Packaged and placed in a landfill authorised, by the appropriate authority.
Specific waste bin in the workshop marked ‘carbon fibre waste only’.
Do not incinerate
How to deal with heat blanket fires?
Turn off power to HBC
Extinguish with dry chemical or carbon dioxide
Evacuate area, call fire service
